Publications

2024

70. Zinah Hilal Khaleel, Young Hyun No,  Do Hyun Bae, Nam Hyeong Kim, Yibing Wu, Hojae Choi, Da Eun Lee, Se Yun Jeong, Toon-Joo Ko, Seong-Gi Kim, Minah Suh, Jin-Chul Kim*, William F. DeGrado*, Ki Hyun Kim*, Yong Ho Kim*, "Computational Design of Light and Ca2+ Switchable Organic-Peptide Hybrid ", Nature Comm (in preparation) 

69.  Trung Thanh Thach, Eun Sung Kang, Nam Hyeong Kim, Hyun-Kyoung Lim, Kayoung Han, Young Hyun No, Kyungtae Kim, Zinah Hilal Khaleel, Kilho Eom, Jiyoung Nam, Bok-Soo Lee, Euna Lee, Han-Joo Kim, Minah Suh, Jaecheol Lee, Yong Ho Kim*,  "Computation-driven domain minimization of SaCas9 for direct delivery-mediated gene suppression", Advanced Materials (in preparation) 

68.  Minji Jeon, Yeon Hwa Kwak, Junsub Kim, Woo Jong Yu, Yong Ho Kim, Byeong-Kwon*, "A Surface Acoustic Wave-Based Sensor for Onsite Detection of Multiple Liquid Drugs", Under revision in Biosensors and Bioelectronics

67. Nam Hyeong Kim, Euna Lee, Sungjun Bae, Bok-Man Kang, Eun Sung Kang, Jae Hoon Jeong, Min-Ho Park, Jeongjae Shin, Hyunsub Ji, Young Hyun No, Jinsun Kim, Taeyoung Park, Seung Won Chung, Seowoo Lee, Seunghee Jeong, Sang Ah Yi, Ki Hong Nam, Jaekyung Hyun, Michael Mark, William F. DeGrado, Han-Joo Kim*, Jaecheol Lee*, Minah Suh*, Yong Ho Kim*, "Super-Selective Brain Delivery of a Therapeutic Antibody", Under revision in Nature Biomedical Engineering 

66. Do Hyun Bae, Hayeon Bae, Hyung-Seok Yu, Banzragch Dorjsembe, Young Hyun No, Taejung Kim, Nam Hyeong Kim, Jin-Woo Kim, Jiyool Kim, Bok-Soo Lee, Ye Ji Kim, Seongchan Park, Zinah Hilal Khaleel, Deok Hyang Sa, Eui-Chul Lee, Jaecheol Lee, Jungyeob Ham*, Jin-Chul Kim*, Yong Ho Kim*  “Peptide-Drug Conjugate with Statistically Designed Transcellular Peptide for Psoriasis-Like Inflammation”, Advanced Healthcare Materials (2024) ASAP.

https://doi.org/10.1002/adhm.202303480 

Abstract

Peptide-drug conjugates (PDCs) are a promising class of drug delivery systems that utilize covalently conjugated carrier peptides with therapeutic agents. PDCs offer several advantages over traditional drug delivery systems including enhanced target engagement, improved bioavailability, and increased cell permeability. However, the development of efficient transcellular peptides capable of effectively transporting drugs across biological barriers remains an unmet need. In this study, physicochemical criteria based on cell-penetrating peptides are employed to design transcellular peptides derived from an antimicrobial peptides library. Among the statistically designed transcellular peptides (SDTs), SDT7 exhibits higher skin permeability, faster kinetics, and improved cell permeability in human keratinocyte cells compared to the control peptide. Subsequently, it is found that 6-Paradol (PAR) exhibits inhibitory activity against phosphodiesterase 4, which can be utilized for an anti-inflammatory PDC. The transcellular PDC (SDT7-conjugated with PAR, named TM5) is evaluated in mouse models of psoriasis, exhibiting superior therapeutic efficacy compared to PAR alone. These findings highlight the potential of transcellular PDCs (TDCs) as a promising approach for the treatment of inflammatory skin disorders. 

65. Suhyeon Kim, Seongmin Ga, Hayeon Bae, Ronald Sluyter, Konstantin Konstantinov, Lok Kumar Shrestha, Yong Ho Kim*, Jung Ho Kim*, Katsuhiko Ariga*, “Multidisciplinary approaches for enzyme biocatalysis in pharmaceuticals: protein engineering, computational biology, and nanoarchitectonics”, EES Catalysis (2024) 2, 14-48 [Front Cover]

■ https://doi.org/10.1039/D3EY00239J 

Abstract

Enzyme biocatalysis is reshaping pharmaceutical synthesis, offering sustainable and efficient pathways for drug discovery and production. This paradigm shift towards eco-friendly methodologies addresses concerns inherent in traditional chemical synthesis. Enzymes, celebrated for their precision and adaptability to mild conditions, are poised as ideal candidates for pharmaceutical applications. Their versatility facilitates the synthesis of diverse pharmaceutical compounds, ensuring precise drug design and minimizing environmental impact. The integration of multidisciplinary approaches, including protein engineering, computational biology, and nanoarchitectonics, holds the potential to propel enzyme biocatalysis even further. Protein engineering utilizes directed evolution and rational design to customize enzymes, enhancing their stability and efficacy. Computational biology aids in deciphering enzymatic mechanisms, while nanoarchitectonics introduces innovative enzyme integration strategies into continuous flow systems. This comprehensive review explores how these multidisciplinary approaches can revolutionize pharmaceutical research and production. The synergy among these disciplines promises to expedite pharmaceutical processes, promote sustainability, optimize efficiency, and elevate precision—aligning perfectly with the evolving requirements of the pharmaceutical industry.

64. Suhyeon Kim, Young Hyun Noh, Ronald Sluyter, Konstantin Konstantinov*, Yong Ho Kim*, Jung Ho Kim*, "Peptide-nanoparticle conjugates as a theranostic platform”, Coordination Chemistry Reviews (2024) 500, 215530-215558

https://doi.org/10.1016/j.ccr.2023.215530 

Abstract

 Theranostic platforms have emerged as advanced systems integrating diagnostic and therapeutic agents to enable personalized medicine tailored to the specific characteristics of each patient's disease. However, conventional theranostic strategies face challenges in achieving high specificity and sensitivity for diagnosis and therapy. This necessitates the development of novel platforms to improve diagnostic accuracy and therapeutic efficacy. Peptide-nanoparticle conjugates (PNCs) have recently gained attention as promising cancer theranostic platforms, offering enhanced specificity and accuracy. PNCs combine the favorable features of nanoparticles with the bioactivity, biocompatibility, and multifunctionality of peptides, overcoming individual material limitations and synergistically controlling relevant biological activities. In this review, we explore the potential of PNCs as highly effective and accurate theranostic platforms, focusing on cancer theranostics. We provide background information and highlight the benefits of PNCs based on their components. We define key properties for desired applications and the corresponding parameters for property control. Representative examples of PNC-based cancer studies are presented based on these properties and parameters. Lastly, we propose guidelines for designing PNCs through a nanoarchitectonics approach to develop a promising cancer theranostic platform. This research contributes to the advancement of personalized medicine and holds great potential for improving patient outcomes in cancer diagnosis and treatment.

63. Kyung Ho Kim, Eunsu Ryu, Zinah Hilal Khaleel, Sung Eun Seo, Lina Kim, Yong Ho Kim, Hyun Gyu Park*, Oh Seok Kwon*

"Plasmonic Digital PCR for Discriminative Detection of SARS-CoV-2 Variants", Biosensors and Bioelectronics (2024) 246, 115859

https://doi.org/10.1016/j.bios.2023.115859

Abstract

We developed a novel strategy for discriminative detection of SARS-CoV-2 variants based on the plasmonic photothermal effect of gold nanofilms and digital polymerase chain reaction (dPCR) technology. This method consists of the gold nanofilm-based dPCR chip fabrication for ultrafast heating and cooling cycles by the plasmonic photothermal effect, the LED quencher immobilization through the interfacing compound on the surface of the gold nanofilm to prevent photoquenching of PCR signaling dye, and the discriminative detection of the variant viruses from the COVID-19 clinical samples by photothermal cycles with fabricated dPCR chips and a portable plasmonic PCR device. Compared to conventional sequencing or RT-qPCR-based variant detection methods, this technology can be effectively applied to point-of-care testing by enabling ultrafast quantitative analysis with a small device. With this method, we successfully detected the delta variant and the omicron variant with a high sensitivity of 10 copies from COVID-19 patients’ clinical samples within 25 min, including reverse transcription. This method can be applied universally to rapid and accurate point-of-care testing for various pandemic viruses as well as the coronavirus.

2023

62. Suhyeon Kim, Nam Hyeong Kim, Zinah Hilal Khaleel, Deok Hyang Sa, Daekyu Choi,  Seongmin Ga, Jiye Jang, Kyeonghyun Kim, Ye Ji Kim, Sukkum Ngullie Chang,  Seon Min Park, Su Yeon Park, Bok-Soo Lee, Jin-Chul Kim, Jaecheol Lee, Seongpil An*, Jae Gyu Park*, Yong Ho Kim*, “Mussel-Inspired Recombinant Adhesive Protein-Based Functionalization for Consistent and Effective Antimicrobial Treatment in Chronic Inflammatory Skin Diseases”, Advanced Therapeutics (2023), 2300353 [Front Cover]

 ■ https://doi.org/10.1002/adtp.202300353 


Abstract

Chronic inflammatory skin diseases, characterized by a vicious cycle of infection and hyperinflammation, necessitate consistent and effective antimicrobial treatment of target lesions to achieve practical therapeutic outcomes. Antimicrobial dressing materials offer notable advantages over conventional therapeutic drugs, including ease of application, extended contact time, and targeted antimicrobial action, resulting in enhanced efficacy in breaking the vicious cycle. In line with these advantages, this study aims to develop a plug-and-playable recombinant adhesive protein (RAP) inspired by the adhesive properties of marine mussels, serving as a durable and effective surface functionalization strategy. By genetically recombining mussel foot protein with antimicrobial peptides, RAP effectively incorporates antimicrobial properties into biomaterials for treating chronic inflammatory skin diseases. The durable adhesion of RAP ensures long-lasting antimicrobial functionality on target surfaces, MFP making it a promising approach to inhibit chronic inflammation. In addition, when dip-coated onto cotton gauze, RAP can be utilized as an antimicrobial patch, effectively suppressing chronic inflammation through the inhibition of bacteria-induced toll-like receptor signaling. These findings underscore the potential of nature-inspired protein-based surface functionalization of biomaterials as a compelling approach to advance the treatment of chronic inflammatory skin diseases.


61. Ye Ji KimMyung Ji Jin,  Zinah Hilal Khaleel, Jo Woon Yi Lee, Seongchan Park, Seongmin Ga, Nam Hyeong Kim, Deok Hyang Sa, Eun Sung Kang, Seul Hee Han, Ji Yeun Lee, Hyo Jung Ku, Sang-Wook Kim, Ki Yong Kim, Jeong Euy Park*, Yong Ho Kim*, Bok-Soo Lee*, "Mechanistic Insights into the Anti-Restenotic Effects of HSP27 and HO1 modulated by Reconstituted HDL on Neointimal Hyperplasia", Scientific Reports (2023) 13(1), 22078

https://doi.org/10.1038/s41598-023-49367-9

Abstract

High-density lipoprotein (HDL) therapy has demonstrated beneficial effects in acute stroke and acute myocardial infarction models by reducing infarct size. In this study, we investigated the inhibitory effects of reconstituted HDL (rHDL) on neointimal hyperplasia and elucidated its underlying mechanism using a balloon injury rat model. Our finding revealed a significant 37% reduction in the intima to media ratio in the arteries treated with 80 mg/kg rHDL compared to those subjected to injury alone (p < 0.05), indicating a specific inhibition of neointimal hyperplasia. In vivo analysis further supported the positive effects of rHDL by demonstrating a reduction in smooth muscle cell (SMC) proliferation and an increase in endothelial cell (EC) proliferation. Additionally, rHDL treatment led to decreased infiltration of leukocytes and downregulated the expression of matrix metallopeptidase 9 (MMP9) in the neointimal area. Notably, rHDL administration resulted in decreased expression of VCAM1 and HIF1α, alongside increased expression of heme oxygenase 1 (HO1) and heat shock protein 27 (HSP27). Overexpression of HSP27 and HO1 effectively inhibited SMC proliferation. Moreover, rHDL-mediated suppression of injury-induced HIF1α coincided with upregulation of HSP27. Interestingly, HSP27 and HO1 had varying effects on the expression of chemokine receptors and rHDL did not exert significant effect on chemokine receptor expression in THP1 cells. These findings underscore the distinct roles of HSP27 and HO1 as potential regulatory factors in the progression of restenosis. Collectively, our study demonstrates that rHDL exerts a potent anti-neointimal hyperplasia effect by reducing leukocytes infiltration and SMC proliferation while promoting EC proliferation. 

60. Seungho Baek, Suhyeon Kim, Sang A Han, Yong Ho Kim*, Sunkook Kim*, Jung Ho Kim*, “Synthesis Strategies and Nanoarchitectonics for High-Performance Transition Metal Dichalcogenide Thin Film Field-effect Transistors”, ChemNanoMat (2023) 9(7), e202300104

https://onlinelibrary.wiley.com/doi/10.1002/cnma.202300104

Abstract

Transition metal dichalcogenides (TMDC) exhibit highly superior electrical properties and are typically obtained through mechanical exfoliation. This method has significant limitations, however, such as patterning issues and non-uniformity, which hinder their application in integrated circuits as transistors and array pixel displays. To overcome these challenges, various large-scale deposition methods have been developed. In this review, we introduce five major methods for TMDC deposition: chemical vapor deposition, physical vapor deposition, atomic layer deposition, pulsed laser deposition, and ink-jet printing. An overview of each method is provided in the following order: surface analysis, electrical characteristics, and limitations of each method are discussed. Furthermore, we present three key strategies for an advanced device fabrication using the discussed deposition methods. By implementing these strategies, we can accelerate the development of highly crystalline and scalable TMDC thin films, which are essential for producing advanced electronic devices with improved performance. Owing to recent technological advancements, TMDC devices have the potential to become the leading material for next-generation semiconductor devices. These devices can be specifically designed and optimized for innovative applications.

59. Suhyeon Kim, Seungho Baek, Ronald Sluyter, Konstantin Konstantinov, Jung Ho Kim*, Sunkook Kim*, Yong Ho Kim* "Wearable and implantable bioelectronics as eco-friendly and patient-friendly integrated nanoarchitectonics for next-generation smart healthcare technology", EcoMat (2023) 5(8), e12356 [Back Cover]

https://doi.org/10.1002/eom2.12356

Abstract

Since the beginning of human history, the demand for effective healthcare systems for diagnosis and treatment of health problems has grown steadily. However, traditional centralized healthcare requires hospital visits, making in-time and long-term healthcare challenging. Bioelectronics has shown potential in patient-friendly healthcare owing to the rapid advances in diverse fields of biology and electronics. In particular, wearable and implantable bioelectronics have emerged as an alternative or adjunct to conventional healthcare. To develop into next-generation healthcare systems, however, custom designs for biological targets with a deepened understanding of the intrinsic features of the target are essential. In addition, bioelectronic systems must be designed eco-friendly for sustainable healthcare. In this review, bioelectronics as eco-friendly and patient-friendly integrated nanoarchitectonics as next-generation smart healthcare technology are described. For an in-depth understanding of biological targets and guidelines for target-tailored design, we discuss target-specific considerations and relevant key parameters of bioelectronic systems with the representative examples.

58. Nasir Sarwar, Zafar Muhammad Shahzad, Usama Bin Humayoun, Suhyeon Kim, Heeyeop Chae, Yong Ho Kim*, Dae Ho Yoon*, "Citrous Lime a Functional Reductive Booster for Oil Mediated Green Synthesis of Bioactive Silver Nanosphere for Healthcare Clothing Applications and their Eco-Mapping with SDGs", Molecules (2023) 28, 2802 

■ https://doi.org/10.3390/molecules28062802 

Abstract

Silver nanoparticles (Ag-NPs) are most effective against pathogens and have widely been studied as antibacterial agents in commodity clothing, medical textile, and other hygiene products. However, prolonged utilization of silver and rapid mutation in bacterium stains has made them resistant to conventional silver agents. On the other hand, strict compliance against excessive utilization of toxic reagents and the current sustainability drive is forcing material synthesis toward green routes with extended functionality. In this study, we proposed an unprecedented chemical-free green synthesis of bioactive Ag-NPs without the incorporation of any chemicals. Cinnamon essential oil (ECO) was used as a bio-reducing agent with and without the mediation of lime extract. A rapid reaction completion with better shape and size control was observed in the vicinity of lime extract when incorporated into the reaction medium. The interaction of natural metabolites and citrus compounds with nanoparticles was established using Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The application of as-prepared nanoparticles on textiles encompasses extended bioactivity to treated fabric with infused easy-care performance. To the best of our knowledge, this is the first reported instance of utilizing bioactive silver nanoparticles as a functional finish, both as an antimicrobial and as for easy care in the absolute absence of toxic chemicals. The easy-care performance of fabric treated with lime-mediated nanoparticles was found to be 141O, which is around 26% better than bare cotton without any significant loss in fabric strength. Furthermore, to enlighten the sustainability of the process, the development traits were mapped with the United Nations Sustainable Development Goals (SDGs), which show significant influence on SDGs 3, 8, 9, and 14. With the effective suspension of microorganisms, added functionality, and eco-mapping with SDGs with the chemical-free synthesis of nanoparticles, widespread utilization can be found in various healthcare and hygiene products along with the fulfillment of sustainability needs. 

57. Nam Hyeong Kim, Sudong Chae, Sang ah Yi,  Deok Hyang Sa, Seungbae Oh, Eun Sung Kang, Suhyeon Kim,  Kyung Hwan Choi Jae Cheol Lee*, Jae Young Choi*, Yong Ho Kim*, "Peptide-assembled single chain atomic crystal enhances pluripotent stem cell differentiation to neuron", Nano Letters (2023) 23, 15, 26859 – 6867

2022

56. Young Hyun No, Nam Hyeong Kim, Zafar Muhammad Shahzad, Seon Hwa Park, Jaecheol Lee, Heeyeop Chae, Wan Soo Yun*, Young Dok Kim*, Yong Ho Kim*, "Effect of Secondary Structure on Adsorption of Peptides onto Hydrophobic Solid Surface by SALDI-TOF and MD simulations" ACS Omega (2022) 48, 43492–43498 

  https://doi.org/10.1021/acsomega.2c03934


Abstract

The adsorption of peptides and proteins on hydrophobic solid surfaces has received considerable research attention owing to their wide applications to biocompatible nanomaterials and nanodevices, such as biosensors and cell adhesion materials with reduced nanomaterial toxicity. However, fundamental understandings about physicochemical hydrophobic interactions between peptides and hydrophobic solid surfaces are still unknown. In this study, we investigate the effect of secondary structures on adsorption energies between peptides and hydrophobic solid surfaces via experimental and theoretical analyses using surface-assisted laser desorption/ionization-time-of-flight (SALDI-TOF) and molecular dynamics (MD) simulations. The hydrophobic interactions between peptides and hydrophobic solid surfaces measured via SALDI-TOF and MD simulations indicate that the hydrophobic interaction of peptides with random coil structures increased more than that of peptides with an α-helix structure when polar amino acids are replaced with hydrophobic amino acids. Additionally, our study sheds new light on the fundamental understanding of the hydrophobic interaction between hydrophobic solid surfaces and peptides that have diverse secondary structures.



55. Minsuk Kwak, Kaden M. Southard, Woon Ryoung Kim, Annie Lin, Nam Hyeong Kim, Ramu Gopalappa, Minji An, Hyun Jung Lee, Seo Hyun Choi, Yunmin Jung, Kunwoo Noh, Justin Farlow, Anastasios Georgakopoulos, Nikolaos K. Robakis, Min K. Kang, Matthew L. Kutys, Daeha Seo, Hyeong Bum Kim, Yong Ho Kim, Jinwoo Cheon, Zev J. Gartner*, Young-wook Jun*, "Adherens junctions organize size-selective proteolytic hotspots critical for Notch signalling" Nature Cell Biology (2022) 24, 1739–1753 

  https://doi.org/10.1038/s41556-022-01031-6


Abstract

Adherens junctions (AJs) create spatially, chemically and mechanically discrete microdomains at cellular interfaces. Here, using a mechanogenetic platform that generates artificial AJs with controlled protein localization, clustering and mechanical loading, we find that AJs also organize proteolytic hotspots for γ-secretase with a spatially regulated substrate selectivity that is critical in the processing of Notch and other transmembrane proteins. Membrane microdomains outside of AJs exclusively organize Notch ligand–receptor engagement (LRE microdomains) to initiate receptor activation. Conversely, membrane microdomains within AJs exclusively serve to coordinate regulated intramembrane proteolysis (RIP microdomains). They do so by concentrating γ-secretase and primed receptors while excluding full-length Notch. AJs induce these functionally distinct microdomains by means of lipid-dependent γ-secretase recruitment and size-dependent protein segregation. By excluding full-length Notch from RIP microdomains, AJs prevent inappropriate enzyme–substrate interactions and suppress spurious Notch activation. Ligand-induced ectodomain shedding eliminates size-dependent segregation, releasing Notch to translocate into AJs for processing by γ-secretase. This mechanism directs radial differentiation of ventricular zone-neural progenitor cells in vivo and more broadly regulates the proteolysis of other large cell-surface receptors such as amyloid precursor protein. These findings suggest an unprecedented role of AJs in creating size-selective spatial switches that choreograph γ-secretase processing of multiple transmembrane proteins regulating development, homeostasis and disease. 

54. Muhammad Shahzad Zafar, Ghulam Dastgeer*, Abul Kalam, Abdullah G. Al-Sehemi, Muhammad Imran, Yong Ho Kim and Heeyeop Chae*, "Precise and Prompt Analyte Detection via Ordered Orientation of Receptor in WSe 2-Based Field Effect Transistor" Nanomaterials (2022) 10, 3390

  https://doi.org/10.3390/nano12081305


Abstract

Field-effect transistors (FET) composed of transition metal dichalcogenide (TMDC) materials have gained huge importance as biosensors due to their added advantage of high sensitivity and moderate bandgap. However, the true potential of these biosensors highly depends upon the quality of TMDC material, as well as the orientation of receptors on their surfaces. The uncontrolled orientation of receptors and screening issues due to crossing the Debye screening length while functionalizing TMDC materials is a big challenge in this field. To address these issues, we introduce a combination of high-quality monolayer WSe2 with our designed Pyrene-based receptor moiety for its ordered orientation onto the WSe2 FET biosensor. A monolayer WSe2 sheet is utilized to fabricate an ideal FET for biosensing applications, which is characterized via Raman spectroscopy, atomic force microscopy, and electrical prob station. Our construct can sensitively detect our target protein (streptavidin) with 1 pM limit of detection within a short span of 2 min, through a one-step functionalizing process. In addition to having this ultra-fast response and high sensitivity, our biosensor can be a reliable platform for point-of-care-based diagnosis.


53. Ghulam Dastgeer*, Zafar Muhammad Shahzad*, Heeyeop Chae, Yong Ho Kim, Byung, Min Ko, Jonghwa Eom*, "Bipolar junction transistor exhibiting excellent output characteristics with a prompt response against the selective protein" Advanced Functional Materials (2022) 10, 1002

  https://doi.org/10.1002/adfm.202204781 


Abstract

Bipolar junction transistors (BJTs), the basic building blocks of integrated circuits, are deployed to control switching applications and logic operations. However, as the thickness of a conventional BJT device approaches a few atoms, its performance decreases substantially. The stacking of atomically thin 2D semiconductor materials is advantageous for manufacturing atomically thin BJT devices owing to the high carrier density of electrons and holes. Here, an atomically thin n–p–n BJT device composed of heavily doped molybdenum ditelluride (n-MoTe2) and germanium selenide (p-GeSe) sheets stacked over each other by van der Waals interactions is reported. In a common-emitter configuration, MoTe2/GeSe/MoTe2 BJT devices exhibit a considerably high current gain (β  =  Ic /Ib = 29.3) at Vbe = 2.5 V. The MoTe2/GeSe/MoTe2 BJT device is employed to detect streptavidin biomolecules as analytes within <10 s. The real-time response of the functionalized BJT device is examined at various concentrations of streptavidin biomolecules ranging from 250 to 5 pm. Such vdW BJT devices can trigger the development of state-of-the-art electronic devices that can be used as biosensors to detect the various kinds of target DNA and proteins like spike protein of Covid-19


52. Jong Uk Kim, Hyejin Park, Jehyung Ok, Juheon Lee, Woojin Junga, Jiwon Kim, Jaehyun Kim, Suhyeon Kim, Yong Ho Kim, Minah Suh,* and Tae-il Kim*, "Cerebrospinal Fluid-philic and Biocompatibility-Enhanced Soft Cranial Window for Long-Term In Vivo Brain Imaging" ACS Applied Materials & Interfaces (2022) 10, 1021

https://doi.org/10.1021/acsami.2c01929


Abstract

Soft, transparent poly(dimethyl siloxane) (PDMS)-based cranial windows in animal models have created many opportunities to investigate brain functions with multiple in vivo imaging modalities. However, due to the hydrophobic nature of PDMS, the wettability by cerebrospinal fluid (CSF) is poor, which may cause air bubble trapping beneath the window during implantation surgery, and favorable heterogeneous bubble nucleation at the interface between hydrophobic PDMS and CSF. This may result in excessive growth of the entrapped bubble under the soft cranial window. Herein, to yield biocompatibility-enhanced, trapped bubble-minimized, and soft cranial windows, this report introduces a CSF-philic PDMS window coated with hydroxyl-enriched poly(vinyl alcohol) (PVA) for long-term in vivo imaging. The PVA-coated PDMS (PVA/PDMS) film exhibits a low contact angle θACA (33.7 ± 1.9°) with artificial CSF solution and maintains sustained CSF-philicity. The presence of the PVA layer achieves air bubble-free implantation of the soft cranial window, as well as induces the formation of a thin wetting film that shows anti-biofouling performance through abundant water molecules on the surface, leading to long-term optical clarity. In vivo studies on the mice cortex verify that the soft and CSF-philic features of the PVA/PDMS film provide minimal damage to neuronal tissues and attenuate immune response. These advantages of the PVA/PDMS window are strongly correlated with the enhancement of cortical hemodynamic changes and the local field potential recorded through the PVA/PDMS film, respectively. This collection of results demonstrates the potential for future microfluidic platforms for minimally invasive CSF extraction utilizing a CSF-philic fluidic passage.

51. Nam Hyeong Kim, Hojae Choi, Zafar Muhammad Shahzad, Hee Soo Ki, Jae Kyoung Lee, Heeyeop Chae, Yong Ho Kim*, "Supramolecular assembly of protein building blocks : From folding to function" NanoConvergence (2022) 10,1186 

  https://doi.org/10.1186/s40580-021-00294-3


Abstract

Several phenomena occurring throughout the life of living things start and end with proteins. Various proteins form one complex structure to control detailed reactions. In contrast, one protein forms various structures and implements other biological phenomena depending on the situation. The basic principle that forms these hierarchical structures is protein self-assembly. A single building block is sufficient to create homogeneous structures with complex shapes, such as rings, filaments, or containers. These assemblies are widely used in biology as they enable multivalent binding, ultra-sensitive regulation, and compartmentalization. Moreover, with advances in the computational design of protein folding and protein–protein interfaces, considerable progress has recently been made in the de novo design of protein assemblies. Our review presents a description of the components of supramolecular protein assembly and their application in understanding biological phenomena to therapeutics.


50. Nasir Sarwar, Usama Bin Humayoun, Mohit Kumar, Ali Nawaz,  Zafar Muhammad Shahazad, Ulfat Rasool, Yong Ho Kim, Dae Ho Yoon*, "A bio based immobilizing matrix for transition metal oxides (TMO) crosslinked cotton: A facile and green processing for photocatalytic self-cleaning and multifunctional textile" Materials Letters (2022) 309, 131338 

 https://doi.org/10.1016/j.matlet.2021.131338

Abstract

Multifunctional textiles, especially with self-cleaning characteristics are among the highly desired products to reduce cleaning effort, water resources and ease of maintenance. In this study the surface properties of cotton are successfully modified through crosslinking of citric acid/chitosan immobilized transition metal oxide (TMO) nano photocatalysts through a facile and cost-effective pad-dry-cure method. The chemical interaction was established through FTIR spectroscopy. All samples present broad-spectrum self-cleaning ability while ZnO immobilized crosslinked fabric was found to be excellent with up to 3 folds enhanced photocatalytic. In parallel to excellent self-cleaning, the as-finished fabrics exhibited extended antimicrobial performance coupled with added easy-care properties and a 28% improvement in strength retention.


2021

  https://doi.org/10.1039/D1CP01061A


Abstract

Amyloid proteins, which aggregate to form highly ordered structures, play a crucial role in various disease pathologies. Despite many previous studies on amyloid fibrils, which are an end product of protein aggregation, the structural characteristics of amyloid proteins in the early stage of aggregation and their related aggregation mechanism still remain elusive. The role of the amino acid sequence in the aggregation-prone structures of amyloid proteins at such a stage is not understood. Here, we have studied the sequence-dependent structural characteristics of islet amyloid polypeptide based on atomistic simulations and spectroscopic experiments. We show that the amino acid sequence determines non-bonded interactions that play a leading role in the formation of aggregation-prone conformations. Specifically, a single point mutation critically changes the population of aggregation-prone conformations, resulting in a change of the aggregation mechanism. Our simulation results were supported by experimental results suggesting that mutation affects the kinetics of aggregation and the structural characteristics of amyloid aggregates. Our study provides an insight into the role of sequence-dependent aggregation-prone conformations in the underlying mechanisms of amyloid aggregation.


2020

48. Sang Ah Yi, Ki Hong Nam, Jihye Yun, Dongmin Gim, Daeho Joe, Yong Ho Kim, Han-Joo Kim, Jeung-Whan Han, Jaecheol Lee *, "Infection of brain organoids and 2D cortical neurons with SARS-CoV-2"Viruses (2020) 12, 1004

  https://doi.org/10.3390/v12091004

Abstract

Since the global outbreak of SARS-CoV-2 (COVID-19), infections of diverse human organs along with multiple symptoms continue to be reported. However, the susceptibility of the brain to SARS-CoV-2, and the mechanisms underlying neurological infection are still elusive. Here, we utilized human embryonic stem cell-derived brain organoids and monolayer cortical neurons to investigate infection of brain with pseudotyped SARS-CoV-2 viral particles. Spike-containing SARS-CoV-2 pseudovirus infected neural layers within brain organoids. The expression of ACE2, a host cell receptor for SARS-CoV-2, was sustained during the development of brain organoids, especially in the somas of mature neurons, while remaining rare in neural stem cells. However, pseudotyped SARS-CoV-2 was observed in the axon of neurons, which lack ACE2. Neural infectivity of SARS-CoV-2 pseudovirus did not increase in proportion to viral load, but only 10% of neurons were infected. Our findings demonstrate that brain organoids provide a useful model for investigating SARS-CoV-2 entry into the human brain and elucidating the susceptibility of the brain to SARS-CoV-2.


47. Bohye Chung, Jaehoon Kim, Jiyoung Nam, Hyunho Kim, Yeju Jeong, Hui-wen Liu, Youngkyu Cho, Yong Ho Kim, Hyun Jeong Oh*, Seok Chung*, “Evaluation of Cell-Penetrating Peptides Using Microfluidic In Vitro 3D Brain Endothelial Barrier”, Macromolecular Bioscience (2020) 20, 1900425

  https://doi.org/10.1002/mabi.201900425


Abstract

In drug delivery to the human brain, blood vessels are a significant hurdle because they restrict the entry of most solutes to protect brain. To overcome this hurdle, an in vitro 3D model for brain endothelial barrier is developed using a microfluidic device with hydrogel providing a 3D extracellular matrix scaffold. Using the model, peptides known to utilize receptor-mediated transcytosis are verified, which has been one of the most promising mechanisms for brain-specific penetration. The cytotoxicity and cellular damage to the peptide are investigated and the receptor-mediated transcytosis and brain endothelial specific penetrating abilities of the peptides in a quantitative manner are demonstrated. As a preclinical test, applying the quantification assays conducted in this study are suggested, including the penetrating ability, cytotoxicity, endothelial damage, and receptor specificity. Using this microfluidic device as an in vitro platform for evaluating various brain targeting drugs and drug carrier candidates is also proposed.


46. Jiyoung Nam, Hyun-Kyoung Lim, Nam Hyeoung Kim, Jong Kwan Park, Eun Sung Kang, Yong-Tae Kim, Chaejeong Heo, One-Sun Lee, Seong-Gi Kim, Wan Soo Yun*, Minah Suh*, Yong Ho Kim*, "Supramolecular Peptide Hydrogel-Based Soft Neural Interface Augments Brain Signals through a Three-Dimensional Electrical Network", ACS Nano (2020) 14, 664-675

  https://doi.org/10.1021/acsnano.9b07396


Abstract

Recording neural activity from the living brain is of great interest in neuroscience for interpreting cognitive processing or neurological disorders. Despite recent advances in neural technologies, development of a soft neural interface that integrates with neural tissues, increases recording sensitivity, and prevents signal dissipation still remains a major challenge. Here, we introduce a biocompatible, conductive, and biostable neural interface, a supramolecular β-peptide-based hydrogel that allows signal amplification via tight neural/hydrogel contact without neuroinflammation. The non-biodegradable β-peptide forms a multihierarchical structure with conductive nanomaterial, creating a three-dimensional electrical network, which can augment brain signal efficiently. By achieving seamless integration in brain tissue with increased contact area and tight neural tissue coupling, the epidural and intracortical neural signals recorded with the hydrogel were augmented, especially in the high frequency range. Overall, our tissuelike chronic neural interface will facilitate a deeper understanding of brain oscillation in broad brain states and further lead to more efficient brain–computer interfaces.


2019

45. Trung Thanh Thach, Do Hyun Bae, Nam Hyeong Kim, Eun Sung Kang, Bok Soo Lee, Kayoung Han, Minsuk Kwak, Hojae Choi, Jiyoung Nam, Taegeun Bae, Minah Suh, Junho K. Hur, Yong Ho Kim*, "Lipopeptide‐Based Nanosome‐Mediated Delivery of Hyperaccurate CRISPR/Cas9 Ribonucleoprotein for Gene Editing" Small (2019) 15, 1903172

  https://doi.org/10.1002/smll.201903172


Abstract

A transient cytosolic delivery system for accurate Cas9 ribonucleoprotein is a key factor for target specificity of the CRIPSR/Cas9 toolkit. Owing to the large size of the Cas9 protein and a long negative strand RNA, the development of the delivery system is still a major challenge. Here, a size-controlled lipopeptide-based nanosome system is reported, derived from the blood-brain barrier-permeable dNP2 peptide which is capable of delivering a hyperaccurate Cas9 ribonucleoprotein complex (HypaRNP) into human cells for gene editing. Each nanosome is capable of encapsulating and delivering ≈2 HypaRNP molecules into the cytoplasm, followed by nuclear localization at 4 h post-treatment without significant cytotoxicity. The HypaRNP thus efficiently enacts endogenous eGFP silencing and editing in human embryonic kidney cells (up to 27.6%) and glioblastoma (up to 19.7% frequency of modification). The lipopeptide-based nanosome system shows superior delivery efficiency, high controllability, and simplicity, thus providing biocompatibility and versatile platform approach for CRISPR-mediated transient gene editing applications.


44. Minsuk Kwak, Wonji Gu, Heekyung Jeong, Hyunjung Lee, Jung-uk Lee, Minji An, Yong Ho Kim, Jae-Hyun Lee, Jinwoo Cheon*, Young-wook Jun*, "Small, clickable, and monovalent magnetofluorescent nanoparticles (MFNs) enable mechanogenetic regulation of receptors in a crowded live cell microenvironment" Nano Letters (2019) 19, 3761-3769

  https://doi.org/10.1021/acs.nanolett.9b00891


Abstract

Multifunctional magnetic nanoparticles have shown great promise as next-generation imaging and perturbation probes for deciphering molecular and cellular processes. As a consequence of multicomponent integration into a single nanosystem, pre-existing nanoprobes are typically large and show limited access to biological targets present in a crowded microenvironment. Here, we apply organic-phase surface PEGylation, click chemistry, and charge-based valency discrimination principles to develop compact, modular, and monovalent magnetofluorescent nanoparticles (MFNs). We show that MFNs exhibit highly efficient labeling to target receptors present in cells with a dense and thick glycocalyx layer. We use these MFNs to interrogate the E-cadherin-mediated adherens junction formation and F-actin polymerization in a three-dimensional space, demonstrating the utility as modular and versatile mechanogenetic probes in the most demanding single-cell perturbation applications.


43. Minsu Jang, Jun Sik Kim, Ji-Hun Kim, Do Hyun Bae, Min Jun Kim, Donghee Son, Yong-Tae Kim, Soong Ho Um*, Yong Ho Kim*, Jinseok Kim*,  "Surface-Controlled Molecular Self-Alignment in Polymer Actuators for Flexible Microrobot Applications" Polymer, (2019) 11, 736

  https://doi.org/10.3390/polym11040736

Abstract

Polymer actuators are important components in lab-on-a-chip and micromechanical systems because of the inherent properties that result from their large and fast mechanical responses induced by molecular-level deformations (e.g., isomerization). They typically exhibit bending movements via asymmetric contraction or expansion with respect to changes in environmental conditions. To enhance the mechanical properties of actuators, a strain gradient should be introduced by regulating the molecular alignment; however, the miniaturization of polymer actuators for microscale systems has raised concerns regarding the complexity of such molecular control. Herein, a novel method for the fabrication of micro-actuators using a simple molecular self-alignment method is presented. Amphiphilic molecules that consist of azobenzene mesogens were located between the hydrophilic and hydrophobic surfaces, which resulted in a splayed alignment. Thereafter, molecular isomerization on the surface induced a large strain gradient and bending movement of the actuator under ultraviolet-light irradiation. Moreover, the microelectromechanical systems allowed for the variation of the actuator size below the micron scale. The mechanical properties of the fabricated actuators such as the bending direction, maximum angle, and response time were evaluated with respect to their thicknesses and lengths. The derivatives of the polymer actuator microstructure may contribute to the development of novel applications in the micro-robotics field.


42. Sunho Park, Teayeop Kim, Danbi Jo, Jin Seok Jung, Gayoung Jo, Yunjeong Park, Yong Ho Kim, Jangho Kim, Kyunghoon Kim, Hoon Hyun, "Bioengineered Short Carbon Nanotubes as Tumor-Targeted Carriers for Biomedical Imaging" Macromolecular Research (2019) 27(8), 833-836

  https://link.springer.com/article/10.1007/s13233-019-7141-1


Abstract

Cancer is one of the leading causes of death in human beings. Therefore, it is important to detect specific target tumors earlier enough in the formative stages of cancer without causing negative side effects and damages to the body. In this study, we proposed bio-engineered short mussel adhesive proteins (MAPs)-carbon nanotubes (CNTs) as specific tumor-targeted carriers for biomedical imaging. Short CNT near-infrared fluorophore (NIRF) hybrid carriers that were developed accumulated in the tumors with exceptional clearance and specific targeting in less time, and these results indicated that bioengineered short CNT-based carriers have great potential for real time tumor imaging.

41.  Pilju Choi, Kwantae Kim, Taejung Kim, Young-Tae Park, Bong Geun Song, Myoung-Sook Shin, Yong Ho Kim, Gwi Seo Hwang, Ki Sung Kang, Jungyeob Ham*, "Application of microwave-irradiation technique in deglycosylation of ginsenosides for improving apoptosis induction in human melanoma SK-MEL-2 cells" Bioorganic & Medicinal Chemistry Letters, (2019) 29, 400-405

  https://doi.org/10.1016/j.bmcl.2018.12.033


Abstract

To increase the contents of medicinally effective ginsenosides, we used high-temperature and high-pressure thermal processing of ginseng by exposing it to microwave irradiation. To determine the anti-melanoma effect, the malignant melanoma SK-MEL-2 cell line was treated with an extract of microwave-irradiated ginseng. Microwave irradiation caused changes in the ginsenoside contents: the amounts of ginsenosides Rg1, Re, Rb1, Rb2, Rc, and Rd were disappeared, while those of less polar ginsenosides, such as Rg3, Rg5, and Rk1, were increased. In particular, the contents of Rk1 and Rg5 markedly increased. Melanoma cells treated with the microwave-irradiated ginseng extract showed markedly increased cell death. The results indicate that the microwave-irradiated ginseng extract induced melanoma cell death via the apoptotic pathway and that the cytotoxic effect of the microwave-irradiated ginseng extract is attributable to the increased contents of specific ginsenosides.


40. Byoungjae Kong, Seokoh Moon, Yuna Kim, Paul Heo, Younghun Jung, Seok-Hyeon Yu, Jinhyo Chung, Choongjin Ban, Yong Ho Kim, Paul Kim, Beom Jeung Hwang, Woo-Jae Chung, Yeon-Kyun Shin, Baik Lin Seong, Dae-Hyuk Kweon,  "Virucidal nano-perforator of viral membrane trapping viral RNAs in the endosome" Nature Communications, (2019) 10, 185-185

 ■ https://doi.org/10.1038/s41467-018-08138-1


Abstract

Membrane-disrupting agents that selectively target virus versus host membranes could potentially inhibit a broad-spectrum of enveloped viruses, but currently such antivirals are lacking. Here, we develop a nanodisc incorporated with a decoy virus receptor that inhibits virus infection. Mechanistically, nanodiscs carrying the viral receptor sialic acid bind to influenza virions and are co-endocytosed into host cells. At low pH in the endosome, the nanodiscs rupture the viral envelope, trapping viral RNAs inside the endolysosome for enzymatic decomposition. In contrast, liposomes containing a decoy receptor show weak antiviral activity due to the lack of membrane disruption. The nanodiscs inhibit influenza virus infection and reduce morbidity and mortality in a mouse model. Our results suggest a new class of antivirals applicable to other enveloped viruses that cause irreversible physical damage specifically to virus envelope by viruses’ own fusion machine. In conclusion, the lipid nanostructure provides another dimension for antiviral activity of decoy molecules. 

2018



39. Jin Woong Lee, Sudong Chae, Seoungbae Oh, Si Hyun Kim, Kyung Hwan Choi, Jimin Jang, Montri Meeseepong, Jongwha Chang, Namsoo Kim, Yong Ho Kim, Nae-Eung Lee, Jung Heon Lee*, Jae-Young Choi*, "Single-chain Atomic Crystal as Extracellular Matrix Mimicking Material with Exceptional Biocompatibility and Bioactivity" Nano Letters, (2018) 18, 7619-7627

  https://doi.org/10.1021/acs.nanolett.8b03201


Abstract

In this study, Mo3Se3 single-chain atomic crystals (SCACs) with atomically small chain diameters of ∼0.6 nm, large surface areas, and mechanical flexibility were synthesized and investigated as an extracellular matrix (ECM)-mimicking scaffold material for tissue engineering applications. The proliferation of L-929 and MC3T3-E1 cell lines increased up to 268.4 ± 24.4% and 396.2 ± 8.1%, respectively, after 48 h of culturing with Mo3Se3 SCACs. More importantly, this extremely high proliferation was observed when the cells were treated with 200 μg mL–1 of Mo3Se3 SCACs, which is above the cytotoxic concentration of most nanomaterials reported earlier. An ECM-mimicking scaffold film prepared by coating Mo3Se3 SCACs on a glass substrate enabled the cells to adhere to the surface in a highly stretched manner at the initial stage of cell adhesion. Most cells cultured on the ECM-mimicking scaffold film remained alive; in contrast, a substantial number of cells cultured on glass substrates without the Mo3Se3 SCAC coating did not survive. This work not only proves the exceptional biocompatible and bioactive characteristics of the Mo3Se3 SCACs but also suggests that, as an ECM-mimicking scaffold material, Mo3Se3 SCACs can overcome several critical limitations of most other nanomaterials.


38. Seoung Rak Lee, Dahae Lee, Jae Sik Yu, René Benndorf, Sullim Lee, Dong-Soo Lee, Jungmoo Huh, Z. Wilhelm de Beer, Yong Ho Kim, Christine Beemelmanns, Ki Sung Kang, Ki Hyun Kim*, "Natalenamides A-C, Cyclic Tripeptides from the Termite-associated Actinomadura sp. RB99"  Molecules, (2018) 23, 3003

  https://doi.org/10.3390/molecules23113003


Abstract

In recent years, investigations into the biochemistry of insect-associated bacteria have increased. When combined with analytical dereplication processes, these studies provide a powerful strategy to identify structurally and/or biologically novel compounds. Non-ribosomally synthesized cyclic peptides have a broad bioactivity spectrum with high medicinal potential. Here, we report the discovery of three new cyclic tripeptides: natalenamides A–C (compounds 13). These compounds were identified from the culture broth of the fungus-growing termite-associated Actinomadura sp. RB99 using a liquid chromatography (LC)/ultraviolet (UV)/mass spectrometry (MS)-based dereplication method. Chemical structures of the new compounds (13) were established by analysis of comprehensive spectroscopic methods, including one-dimensional (1H and 13C) and two-dimensional (1H-1H-COSY, HSQC, HMBC) nuclear magnetic resonance spectroscopy (NMR), together with high-resolution electrospray ionization mass spectrometry (HR-ESIMS) data. The absolute configurations of the new compounds were elucidated using Marfey’s analysis. Through several bioactivity tests for the tripeptides, we found that compound 3 exhibited significant inhibitory effects on 3-isobutyl-1-methylxanthine (IBMX)-induced melanin production. The effect of compound 3 was similar to that of kojic acid, a compound extensively used as a cosmetic material with a skin-whitening effect


  https://iopscience.iop.org/article/10.1088/1361-6528/aabd8a/meta


Abstract

Amyloid fibrils have recently been highlighted due to their excellent mechanical properties, which not only play a role in their biological functions but also imply their applications in biomimetic material design. Despite recent efforts to unveil how the excellent mechanical properties of amyloid fibrils originate, it has remained elusive how the anisotropic nanomechanical properties of hierarchically structured amyloid fibrils are determined. Here, we characterize the anisotropic nanomechanical properties of hierarchically structured amyloid fibrils using atomic force microscopy experiments and atomistic simulations. It is shown that the hierarchical structure of amyloid fibrils plays a crucial role in determining their radial elastic property but does not make any effect on their bending elastic property. This is attributed to the role of intermolecular force acting between the filaments (constituting the fibril) on the radial elastic modulus of amyloid fibrils. Our finding illustrates how the hierarchical structure of amyloid fibrils encodes their anisotropic nanomechanical properties. Our study provides key design principles of amyloid fibrils, which endow valuable insight into the underlying mechanisms of amyloid mechanics.


36. Eun Sung Kang, Yong-Tae Kim, Young-Seon Ko, Nam Hyeong Kim, Geonhee Cho, Yang Hoon Huh, Ji-Hun Kim, Jiyoung Nam, Trung Thand Thach, David Youn, Young Dok Kim, Wan Soo Yun, William F. DeGrado, Sung Teol Kim, Paula T. Hammond, Jaeyoung Lee, Young-Uk Kwon, Don-Hyung Ha*, Yong Ho Kim*, “Peptide-Programmable Nanoparticle Superstructures with Tailored Electrocatalytic Activity”  ACS Nano, (2018) 12, 6554–6562

  https://doi.org/10.1021/acsnano.8b01146


Abstract

Biomaterials derived via programmable supramolecular protein assembly provide a viable means of constructing precisely defined structures. Here, we present programmed superstructures of AuPt nanoparticles (NPs) on carbon nanotubes (CNTs) that exhibit distinct electrocatalytic activities with respect to the nanoparticle positions via rationally modulated peptide-mediated assembly. De novo designed peptides assemble into six-helix bundles along the CNT axis to form a suprahelical structure. Surface cysteine residues of the peptides create AuPt-specific nucleation site, which allow for precise positioning of NPs onto helical geometries, as confirmed by 3-D reconstruction using electron tomography. The electrocatalytic model system, i.e., AuPt for oxygen reduction, yields electrochemical response signals that reflect the controlled arrangement of NPs in the intended assemblies. Our design approach can be expanded to versatile fields to build sophisticated functional assemblies.


2017


35. Kyo Ree Lee, Eun Sung Kang, Yong-Tae Kim, Nam Hyeong Kim, David Youn, Young Dok Kim*, Jaeyoung Lee*, Yong Ho Kim*, “Enhancement of Catalytic Activity of a Programmed Gold Nanoparticle Superstructure Modulated by Supramolecular Protein Assembly” Catalyst Today, (2017) 295, 95-101

  https://doi.org/10.1016/j.cattod.2017.06.008


Abstract

Improving the efficiency of the oxygen reduction reaction (ORR) for use in commercial fuel cells has been the subject of diverse synthetic research activities. However, due to their inferior catalytic performance and dispensability, there are still limitations to achieving breakthroughs regarding ORR catalytic activity using carbon nanomaterials, despite their high electron-transfer and mass-transport properties. In this study, we mimicked nature by using a biomineralization approach for controlling the growth of inorganic materials and demonstrated improved ORR values. The designed peptide, Hexcoil-Ala, is able to supramolecular assembly on single-walled carbon nanotubes (SWNTs), leading to SWNTs that are well dispersed in aqueous solution. In order to direct gold nanoparticle (AuNP) nucleation sites, we substitute two residues in Hexcoil-Ala with cysteine to provide the mutated peptide, HexCoil-Ala-2Cys. This peptide affords a sophisticated, size-controlled, and well-dispersed arrangement of AuNPs. High-resolution transmission electron microscopy studies confirmed the homogeneously well-aligned distribution of nanosized AuNPs on the HexCoil-Ala-2Cys structure, along the direction of SWNT axis. The (AuNPs/P-SWNT) composite in water provides dispersed and stable metallic nanoparticles of electrostatically modified Au through synergistic effects involving the peptide. Consequently, this catalyst exhibits improved ORR performance compared to bulk gold and even, in case of number of electrons (n) transferred, higher than the number of Pt/C. X-ray photoelectron and Raman spectroscopies reveal the details of the electronic interactions among the components of the AuNP/P-SWNT composite, and how they facilitate the four-electron reaction pathway. This study provides valuable information for the optimization of catalyst synthesis and precise particle-size control, leading to stable, water-dispersive composites, with improved electronic properties for enhanced ORR performance in fuel cells.


34. Ji Eun Kim, Young Hyun No, Joo Nam Kim, Yong Seon Shin, Won Tae Kang, Young Rae Kim, Kun-Nyun Kim, Yong Ho Kim*, Woo Jong Yu*, “Highly sensitive graphene biosensor by monomolecular self-assembly of receptors on graphene surface” Applied Physics Letters (2017) 110, 203702

  https://doi.org/10.1063/1.4983084


Abstract

Graphene has attracted a great deal of interest for applications in bio-sensing devices because of its ultra-thin structure, which enables strong electrostatic coupling with target molecules, and its excellent electrical mobility promising for ultra-fast sensing speeds. However, thickly stacked receptors on the graphene's surface interrupts electrostatic coupling between graphene and charged biomolecules, which can reduce the sensitivity of graphene biosensors. Here, we report a highly sensitive graphene biosensor by the monomolecular self-assembly of designed peptide protein receptors. The graphene channel was non-covalently functionalized using peptide protein receptors via the π-π interaction along the graphene's Bravais lattice, allowing ultra-thin monomolecular self-assembly through the graphene lattice. In thickness dependent characterization, a graphene sensor with a monomolecular receptor (thickness less than 3 nm) showed five times higher sensitivity and three times higher voltage shifts than graphene sensors with thick receptor stacks (thicknesses greater than 20 nm), which is attributed to excellent gate coupling between graphene and streptavidin via an ultrathin receptor insulator. In addition to having a fast-inherent response time (less than 0.6 s) based on fast binding speed between biotin and streptavidin, our graphene biosensor is a promising platform for highly sensitive real-time monitoring of biomolecules with high spatiotemporal resolution.


33. Young Hyun No, Nam Hyeong Kim, Bramaramba Gnapareddy, Bumjoon Choi, Yong-Tae Kim, Sreekantha Reddy Dugasani, One-Sun Lee, Kook-Han Kim, Young-Seon Ko, Seungwoo Lee, Sang Woo Lee, Sung Ha Park*, Kil Ho Eom*, Yong Ho Kim*, “Nature-Inspired Construction of Two-Dimensionally Self-Assembled Peptide on Pristine Graphene” The Journal of Physical Chemistry Letters (2017) 8, 3734-3739

  https://doi.org/10.1021/acs.jpclett.7b00996


Abstract

Peptide assemblies have received significant attention because of their important role in biology and applications in bionanotechnology. Despite recent efforts to elucidate the principles of peptide self-assembly for developing novel functional devices, peptide self-assembly on two-dimensional nanomaterials has remained challenging. Here, we report nature-inspired two-dimensional peptide self-assembly on pristine graphene via optimization of peptide–peptide and peptide–graphene interactions. Two-dimensional peptide self-assembly was designed based on statistical analyses of >104 protein structures existing in nature and atomistic simulation-based structure predictions. We characterized the structures and surface properties of the self-assembled peptide formed on pristine graphene. Our study provides insights into the formation of peptide assemblies coupled with two-dimensional nanomaterials for further development of nanobiocomposite devices. 

32. Sun-Hee Cho, Jung-Ran Noh, Mi Young Cho, Min-Jeong Go, Yong-Hoon Kim, Eun Sung Kang, Yong Ho Kim, Chul-Ho Lee*, and Yong Taik Lim* "An injectable collagen/poly(γ-glutamic acid) hydrogel as a scaffold of stem cells and α-lipoic acid for enhanced protection against renal dysfunction" Biomaterials Science, (2017) 5, 285-294

  https://pubs.rsc.org/en/content/articlehtml/2017/bm/c6bm00711b


Abstract

Mesenchymal stem cells (MSCs) can ameliorate renal injury and accelerate repair of acute kidney injury. Herein, we developed a collagen/poly(γ-glutamic acid) (γ-PGA) hydrogel as an injectable scaffold for the delivery of mouse MSCs (mMSCs) and anti-oxidant drugs into injured sites. By the introduction of γ-PGA into conventional collagen, the viscosity of collagen was reduced at ambient temperature for easy handling, while the elastic and viscous moduli of collagen were increased and a new porous structure was generated near body temperature. When in situ gel-forming collagen/γ-PGA hydrogels loaded with mMSCs and α-lipoic acid (LA) were administered to a mouse model of renal dysfunction, they significantly attenuated the level of blood urea nitrogen and creatinine, which resulted from the increased retention of therapeutic mMSCs and the controlled release of anti-oxidant drugs at the injured site. These findings suggested that this novel type of hydrogel could be applied as an injectable scaffold for use in regenerative medicine. 

  https://doi.org/10.1016/j.bbrc.2016.10.150


Abstract

Streptococcus pneumoniae is a major infectious agent responsible for pneumonia, otitis media, sepsis and meningitis. Pneumococcal surface protein A (PspA) is a well-characterized virulence factor localized on the surface and a target for vaccine development. In this study, we screened a single-chain antibody variable fragment (scFv) using phage display from a human synthetic library to select a clone 2B11. Affinity (Kd) of 2B11 was measured to be 5 nM using biolayer interferometry. 2B11 exhibited a dose-dependent recognition of recombinant PspA with no cross-reactivity towards pneumococcal antigens. The epitope on PspA was defined to residues 231–242 by mutational analysis. Molecular docking analysis supported the experimentally determined epitope, suggesting that the helix spanning residues 231–242 can bind to 2B11 with residues in the CDR-H3 (complementarity determining region 3 in the heavy chain) actively participating in the molecular contacts. Comparison of 2B11 with a commercial PspA antibody revealed that 2B11 exhibited a better specificity towards recombinant PspA antigen. 2B11 was capable of detecting endogenous PspA from pneumococcal lysates with affinity similar to that of the commercial antibody. Our study provides a molecular tool for biosensors detecting pneumococcal diseases. 

2016


30. Mahendra Prasad Bhatt, Yeon-Ju Lee, Se-Hui Jung, Yong Ho Kim, Jong Yun Hwang, Eun-Taek Han, Won Sun Park, Seok-Ho Hong, Young-Myeong Kim, Kwon-Soo Ha* "C-peptide protects against hyperglycemic memory and vascular endothelial cell apoptosis" Journal of Endocrinology,  (2016) 231, 97-108

  https://pubs.rsc.org/en/content/articlehtml/2017/bm/c6bm00711b


Abstract

Mesenchymal stem cells (MSCs) can ameliorate renal injury and accelerate repair of acute kidney injury. Herein, we developed a collagen/poly(γ-glutamic acid) (γ-PGA) hydrogel as an injectable scaffold for the delivery of mouse MSCs (mMSCs) and anti-oxidant drugs into injured sites. By the introduction of γ-PGA into conventional collagen, the viscosity of collagen was reduced at ambient temperature for easy handling, while the elastic and viscous moduli of collagen were increased and a new porous structure was generated near body temperature. When in situ gel-forming collagen/γ-PGA hydrogels loaded with mMSCs and α-lipoic acid (LA) were administered to a mouse model of renal dysfunction, they significantly attenuated the level of blood urea nitrogen and creatinine, which resulted from the increased retention of therapeutic mMSCs and the controlled release of anti-oxidant drugs at the injured site. These findings suggested that this novel type of hydrogel could be applied as an injectable scaffold for use in regenerative medicine. 

29. Young-Seon Ko, Yong-Tae Kim, Ji-Hun Kim, Dae Han Kim, Kook-Han Kim, Wan Soo Yun, Young Dok Kim*, Jaeyoung Lee* and Yong Ho Kim*, "Peptide-based bimetallic nanostructures with tailored surface compositions and catalytic activities" CrysEngComm, (2016) 18, 6024-6028

  https://pubs.rsc.org/en/content/articlehtml/2017/bm/c6bm00711b


Abstract

Mesenchymal stem cells (MSCs) can ameliorate renal injury and accelerate repair of acute kidney injury. Herein, we developed a collagen/poly(γ-glutamic acid) (γ-PGA) hydrogel as an injectable scaffold for the delivery of mouse MSCs (mMSCs) and anti-oxidant drugs into injured sites. By the introduction of γ-PGA into conventional collagen, the viscosity of collagen was reduced at ambient temperature for easy handling, while the elastic and viscous moduli of collagen were increased and a new porous structure was generated near body temperature. When in situ gel-forming collagen/γ-PGA hydrogels loaded with mMSCs and α-lipoic acid (LA) were administered to a mouse model of renal dysfunction, they significantly attenuated the level of blood urea nitrogen and creatinine, which resulted from the increased retention of therapeutic mMSCs and the controlled release of anti-oxidant drugs at the injured site. These findings suggested that this novel type of hydrogel could be applied as an injectable scaffold for use in regenerative medicine. 

Graphical abstract: Peptide-based bimetallic nanostructures with tailored surface compositions and their oxygen electroreduction activities

28. Jiyoung Nam, Yong-Tae Kim, Aeyeon Kang, Kook-Han Kim, Kyo Ree Lee, Wan Soo Yun*, Yong Ho Kim* "Lipid reconstitution-enabled formation of gold nanoparticle clusters for mimetic cellular membrane" Journal of Nanomaterials, in press

  https://pubs.rsc.org/en/content/articlehtml/2017/bm/c6bm00711b


Abstract

Mesenchymal stem cells (MSCs) can ameliorate renal injury and accelerate repair of acute kidney injury. Herein, we developed a collagen/poly(γ-glutamic acid) (γ-PGA) hydrogel as an injectable scaffold for the delivery of mouse MSCs (mMSCs) and anti-oxidant drugs into injured sites. By the introduction of γ-PGA into conventional collagen, the viscosity of collagen was reduced at ambient temperature for easy handling, while the elastic and viscous moduli of collagen were increased and a new porous structure was generated near body temperature. When in situ gel-forming collagen/γ-PGA hydrogels loaded with mMSCs and α-lipoic acid (LA) were administered to a mouse model of renal dysfunction, they significantly attenuated the level of blood urea nitrogen and creatinine, which resulted from the increased retention of therapeutic mMSCs and the controlled release of anti-oxidant drugs at the injured site. These findings suggested that this novel type of hydrogel could be applied as an injectable scaffold for use in regenerative medicine. 

  https://www.nature.com/articles/srep27818?origin=ppub


Abstract

Chronic in vivo imaging and electrophysiology are important for better understanding of neural functions and circuits. We introduce the new cranial window using soft, penetrable, elastic, and transparent, silicone-based polydimethylsiloxane (PDMS) as a substitute for the skull and dura in both rats and mice. The PDMS can be readily tailored to any size and shape to cover large brain area. Clear and healthy cortical vasculatures were observed up to 15 weeks post-implantation. Real-time hemodynamic responses were successfully monitored during sensory stimulation. Furthermore, the PDMS window allowed for easy insertion of microelectrodes and micropipettes into the cortical tissue for electrophysiological recording and chemical injection at any location without causing any fluid leakage. Longitudinal two-photon microscopic imaging of Cx3Cr1+/− GFP transgenic mice was comparable with imaging via a conventional glass-type cranial window, even immediately following direct intracortical injection. This cranial window will facilitate direct probing and mapping for long-term brain studies. 

26. Dong-Cheol Jeong, Amjed Javid, Long Wen, Eun Jung Choi, Su Yeon Park, Yong Ho Kim, Jeon Geon Han, Changsik Song*, "Low-Temperature Plasma Polymerization of Dicyclopentadiene for Anti-Corrosion Properties", Polymer, (2016)  92, 133-139

  https://doi.org/10.1016/j.polymer.2016.03.094


Abstract

We successfully synthesized plasma-polymerized films from a highly crosslinkable monomer, dicyclopentadiene (a norbornene derivative), using a low-temperature plasma process as an anti-corrosion coating for Cu metal plates. Plasma-enhanced deposition of polymer films from a dicyclopentadiene precursor was carried out using radio frequency (13.6 MHz) plasma generation with argon or nitrogen carrier gas and varying the input power (50–200 W). The surfaces of plasma-polymers synthesized using an argon carrier gas were more hydrophobic than those prepared with a nitrogen carrier gas, which can be attributed to the formation of CNCHx bonds due to nitrogen dissociation. The inhibition efficiency (IE) for Cu corrosion was estimated from potentiodynamic polarization curves to be enhanced up to ∼93%, which was proportional to the input power in the polymer synthesis. Interestingly, when using a nitrogen carrier gas, the plasma-polymerized films showed shifts of the corrosion potential to negative values. We suspect that nitrogen insertion into the films may result in polarization between nitrogen and copper atoms. 

25. Kook-Han Kim, Dong Kuyn Ko, Yong-Tae Kim, Nam Hyeong Kim, Jayadeep Paul, Christopher B. Murray, Rudresh Acharya*, William F. DeGrado*, Yong Ho Kim*, Gevorg Grigoryan*, “Protein-directed self-assembly of a fullerene crystal” Nature Communications, (2016)  7, 11429

  https://www.nature.com/articles/ncomms11429


Abstract

Learning to engineer self-assembly would enable the precise organization of molecules by design to create matter with tailored properties. Here we demonstrate that proteins can direct the self-assembly of buckminsterfullerene (C60) into ordered superstructures. A previously engineered tetrameric helical bundle binds C60 in solution, rendering it water soluble. Two tetramers associate with one C60, promoting further organization revealed in a 1.67-Å crystal structure. Fullerene groups occupy periodic lattice sites, sandwiched between two Tyr residues from adjacent tetramers. Strikingly, the assembly exhibits high charge conductance, whereas both the protein-alone crystal and amorphous C60 are electrically insulating. The affinity of C60 for its crystal-binding site is estimated to be in the nanomolar range, with lattices of known protein crystals geometrically compatible with incorporating the motif. Taken together, these findings suggest a new means of organizing fullerene molecules into a rich variety of lattices to generate new properties by design. 

24. Mirela Mustata, Yong Ho Kim*, Jian Zhang, William F. DeGrado, Gevorg Grigoryan*, Meni Wanunu*, "Graphene Symmetry Amplified by Designed Peptide Self-Assembly " Biophysical Journal, (2016)  110, 2507-2516

  https://doi.org/10.1016/j.bpj.2016.04.037


Abstract

We present a strategy for designed self-assembly of peptides into two-dimensional monolayer crystals on the surface of graphene and graphite. As predicted by computation, designed peptides assemble on the surface of graphene to form very long, parallel, in-register β-sheets, which we call β-tapes. Peptides extend perpendicularly to the long axis of each β-tape, defining its width, with hydrogen bonds running along the axis. Tapes align on the surface to create highly regular microdomains containing 4-nm pitch striations. Moreover, in agreement with calculations, the atomic structure of the underlying graphene dictates the arrangement of the β-tapes, as they orient along one of six directions defined by graphene’s sixfold symmetry. A cationic-assembled peptide surface is shown here to strongly adhere to DNA, preferentially orienting the double helix along β-tape axes. This orientational preference is well anticipated from calculations, given the underlying peptide layer structure. These studies illustrate how designed peptides can amplify the Ångstrom-level atomic symmetry of a surface onto the micrometer scale, further imparting long-range directional order onto the next level of assembly. The remarkably stable nature of these assemblies under various environmental conditions suggests applications in enzymelike catalysis, biological interfaces for cellular recognition, and two-dimensional platforms for studying DNA-peptide 

23. Yong-Tae Kim, Kook-Han Kim, Eun Sung Kang, Geoncheol Jo, Se Young Ahn, Seon Hwa Park, Sung ll Kim, Saem Mun, Kyuwon Baek, Byeongyoon Kim, Kwangyeol Lee*, Wan Soo Yun*, Yong Ho Kim*, “Synergistic effect of detection and separation for pathogen using magnetic clusters” Bioconjugate Chemistry, (2016) 27, 59-65

  https://doi.org/10.1021/acs.bioconjchem.5b00681


Abstract

Early diagnosis of infectious diseases is important for treatment; therefore, selective and rapid detection of pathogenic bacteria is essential for human health. We report a strategy for highly selective detection and rapid separation of pathogenic microorganisms using magnetic nanoparticle clusters. Our approach to develop probes for pathogenic bacteria, including Salmonella, is based on a theoretically optimized model for the size of clustered magnetic nanoparticles. The clusters were modified to provide enhanced aqueous solubility and versatile conjugation sites for antibody immobilization. The clusters with the desired magnetic property were then prepared at critical micelle concentration (CMC) by evaporation-induced self-assembly (EISA). Two different types of target-specific antibodies for H- and O-antigens were incorporated on the cluster surface for selective binding to biological compartments of the flagella and cell body, respectively. For the two different specific binding properties, Salmonella were effectively captured with the O-antibody-coated polysorbate 80-coated magnetic nanoclusters (PCMNCs). The synergistic effect of combining selective targeting and the clustered magnetic probe leads to both selective and rapid detection of infectious pathogens. 

22. Jae-Byum Chang, Yong Ho Kim, Evan Thompson, Young Hyun No, Nam Hyeong Kim, Jose Arrieta, Vitor Manfrinato, Amy E. Keating*, Karl K. Berggren*, “The Orientations of Large Aspect-Ratio Coiled-Coil Proteins Attached to Gold Nanostructures” Small, (2016) 12, 1498-1505

  https://doi.org/10.1002/smll.201502419


Abstract

Methods for patterning biomolecules on a substrate at the single molecule level have been studied as a route to sensors with single-molecular sensitivity or as a way to probe biological phenomena at the single-molecule level. However, the arrangement and orientation of single biomolecules on substrates has been less investigated. Here, the arrangement and orientation of two rod-like coiled-coil proteins, cortexillin and tropomyosin, around patterned gold nanostructures is examined. The high aspect ratio of the coiled coils makes it possible to study their orientations and to pursue a strategy of protein orientation via two-point attachment. The proteins are anchored to the surfaces using thiol groups, and the number of cysteine residues in tropomyosin is varied to test how this variation affects the structure and arrangement of the surface-attached proteins. Molecular dynamics studies are used to interpret the observed positional distributions. Based on initial studies of protein attachment to gold post structures, two 31-nm-long tropomyosin molecules are aligned between the two sidewalls of a trench with a width of 68 nm. Because the approach presented in this study uses one of twenty natural amino acids, this method provides a convenient way to pattern biomolecules on substrates using standard chemistry. 

  https://doi.org/10.1016/j.cplett.2015.09.027


Abstract

The pH, one of the critical factors in determining the size distribution of gold nanoparticles (AuNPs), is not maintained at a constant value during the synthetic reaction. In this work, AuNPs were synthesized in the pH range of 5.5–10.5 and the pH was monitored in situ throughout the whole synthetic process. It was found that the citrate-based AuNP synthesis could be divided into two stages according to phases of pH change: a pH-decreasing early stage and a pH-increasing final stage. The narrowest size distribution at pH 7.5 can be well understood with these two phases of pH change. 

  https://doi.org/10.1016/j.apsusc.2015.06.122


Abstract

TiO2 nanoparticles were used as MALDI matrix for detecting dimethyl methylphosphate (DMMP) and its efficiency, in terms of DMMP signal intensity in the MALDI-MS analysis, was compared with that of polydimethylsiloxane (PDMS)-coated TiO2 matrix. Intensity of the DMMP signal in the MALDI-MS analysis was significantly increased by using PDMS-coated TiO2 matrix instead of bare ones. It was verified using FT-IR that the enhanced DMMP signal upon PDMS coating on TiO2 matrix is a result of weaker interactions between DMMP molecule and the PDMS-covered surface than that of bare TiO2. A weaker DMMP-matrix interaction can facilitate desorption of DMMP from the matrix surface in the MALDI process, yielding a higher sensitivity to DMMP in the MALDI-MS. 

19. Jaehyun Yang, Yeahyun Gu, Eunha Lee, Hyangsook Lee, Sang Han Park, Mann-Ho Cho, Yong Ho Kim, Yong-Hoon Kim, Hyoungsub Kim*, "Wafer-scale synthesis of thickness-controllable MoS2 films via solution-processing using a dimethylformamide/n-butylamine/2-aminoethanol solvent system" Nanoscale, (2015) 7, 9311-9319

  https://doi.org/10.1039/C5NR01486G


Abstract

The wafer-scale synthesis of two-dimensional molybdenum disulfide (MoS2) films, with high layer-controllability and uniformity, remains a significant challenge in the fields of nano and optoelectronics. Here, we report the highly thickness controllable growth of uniform MoS2 thin films on the wafer-scale via a spin-coating route. Formulation of a dimethylformamide-based MoS2 precursor solution mixed with additional amine- and amino alcohol-based solvents (n-butylamine and 2-aminoethanol) allowed for the formation of a uniform coating of MoS2 thin films over a 2 inch wafer-scale SiO2/Si substrate. In addition, facile control of the average number of stacking layers is demonstrated by simply manipulating the concentration of the precursor solution. Various characterization results reveal that the synthesized MoS2 film has wafer-scale homogeneity with excellent crystalline quality and a stoichiometric chemical composition. To further demonstrate possible device applications, a mostly penta-layered MoS2 thin film was integrated into a top-gated field-effect transistor as the channel layer and we also successfully transferred our films onto transparent/flexible substrates. 

18. Kyungtae Kang, Sunghoon Joo, Ji Yu Choi, Sujeong Geum, Seok-Pyo Hong, Seung-Yeul Lee, Yong Ho Kim, Seong-Min Kim, Myung-Han Yoon, Yoonkey Nam, Kyung-Bok Lee, Hee-Yoon Lee, Insung S. Choi*, "Tissue-Based Metabolic Labeling of Polysialic Acids in Living Primary Hippocampal Neurons" Proceedings of the National Academy of Sciences, (2015) 112, E241-E248

  https://doi.org/10.1073/pnas.1419683112


Abstract

The posttranslational modification of neural cell-adhesion molecule (NCAM) with polysialic acid (PSA) and the spatiotemporal distribution of PSA-NCAM play an important role in the neuronal development. In this work, we developed a tissue-based strategy for metabolically incorporating an unnatural monosaccharide, peracetylated N-azidoacetyl-D-mannosamine, in the sialic acid biochemical pathway to present N-azidoacetyl sialic acid to PSA-NCAM. Although significant neurotoxicity was observed in the conventional metabolic labeling that used the dissociated neuron cells, neurotoxicity disappeared in this modified strategy, allowing for investigation of the temporal and spatial distributions of PSA in the primary hippocampal neurons. PSA-NCAM was synthesized and recycled continuously during neuronal development, and the two-color labeling showed that newly synthesized PSA-NCAMs were transported and inserted mainly to the growing neurites and not significantly to the cell body. This report suggests a reliable and cytocompatible method for in vitro analysis of glycans complementary to the conventional cell-based metabolic labeling for chemical glycobiology. 

17. Qinke Wu, Seong Jun jung, Joohyun Lee, Sungkyu Jang, Insu Jeon, Hwansoo Suh, Yong Ho Kim, Young Hee Lee*, Sungjoo Lee*, Young Jae Song*, "Controllable poly-crystalline bilayered and multilayered graphene film growth by reciprocal chemical vapor deposition" Nanoscale, (2015) 7, 10357-10361

  https://doi.org/10.1039/C5NR02716K


Abstract

We report the selective growth of large-area bilayered graphene film and multilayered graphene film on copper. This growth was achieved by introducing a reciprocal chemical vapor deposition (CVD) process that took advantage of an intermediate h-BN layer as a sacrificial template for graphene growth. A thin h-BN film, initially grown on the copper substrate using CVD methods, was locally etched away during the subsequent graphene growth under residual H2 and CH4 gas flows. Etching of the h-BN layer formed a channel that permitted the growth of additional graphene adlayers below the existing graphene layer. Bilayered graphene typically covers an entire Cu foil with domain sizes of 10–50 μm, whereas multilayered graphene can be epitaxially grown to form islands a few hundreds of microns in size. This new mechanism, in which graphene growth proceeded simultaneously with h-BN etching, suggests a potential approach to control graphene layers for engineering the band structures of large-area graphene for electronic device applications. 

16. Suk Bon Yoon, Dae Keun Park, Aeyeon Kang, Yong-Tae Kim, Yong Ho Kim*, Wan Soo Yun*, "Formation of Double Shells with Different Porosity on Silica Nanocores" Bull. Korean Chem Soc (2015) 33, 789-792

  https://doi.org/10.1002/bkcs.10146


Abstract

We report on the preparation of hierarchically doubled shells of different porosity on monodispersive silica nanocores by the direct formation of the outer shell with larger mesopores (D > similar to 2.5 nm) on the surface of the initial single shell of smaller mesopores (D < similar to 2.5 nm). An organic template solution containing cetyltrimethylammonium bromide, 1,3,5-trimethylbenzene, and decane was used for the formation of the larger mesoporous shells, while the initial shell was prepared with the use of only one type of structure-directing agent, namely cetyltrimethylammonium bromide. The resulting core-shell silica nanoparticles are spherical, monodispersive, and show a distinct bimodal porosity. Pore sizes of those shells were easily controlled by varying the molar ratio of the pore expansion agents.  

  https://doi.org/10.1166/jnn.2015.10263


Abstract

Ordered mesoporous MnO, Mn3O4, Mn2O3 and MnO2 materials with 3-D pore structure were successfully synthesized via a nano-replication method by using ordered mesoporous silica, KIT-6 (Cubic Ia3d space group mesostructure) as the template under specific oxidation and reduction conditions. Notably, ordered mesoporous MnO with a crystalline wall (rock salt structure) was synthesized for the first time, to the best of our knowledge. The synthesis of the ordered mesoporous MnO was achieved by reducing the ordered mesoporous Mn3O4 under an H2 atmosphere, while preserving the ordered mesostructure and crystalline wall throughout the solid/solid transformation. All of the ordered mesoporous manganese oxides with different crystal structures and oxidation states demonstrated almost the same spherical-like morphology with several hundred nanometers of particles. The synthesized ordered mesoporous manganese oxides had uniform dual mesopores (2–3 nm, and ∼20 nm) and crystalline frameworks with large surface areas (86–140 m2/g) and pore volumes (0.27–0.33 cm3/g). 

  https://doi.org/10.1166/jnn.2015.10263


Abstract

Ordered mesoporous MnO, Mn3O4, Mn2O3 and MnO2 materials with 3-D pore structure were successfully synthesized via a nano-replication method by using ordered mesoporous silica, KIT-6 (Cubic Ia3d space group mesostructure) as the template under specific oxidation and reduction conditions. Notably, ordered mesoporous MnO with a crystalline wall (rock salt structure) was synthesized for the first time, to the best of our knowledge. The synthesis of the ordered mesoporous MnO was achieved by reducing the ordered mesoporous Mn3O4 under an H2 atmosphere, while preserving the ordered mesostructure and crystalline wall throughout the solid/solid transformation. All of the ordered mesoporous manganese oxides with different crystal structures and oxidation states demonstrated almost the same spherical-like morphology with several hundred nanometers of particles. The synthesized ordered mesoporous manganese oxides had uniform dual mesopores (2–3 nm, and ∼20 nm) and crystalline frameworks with large surface areas (86–140 m2/g) and pore volumes (0.27–0.33 cm3/g). 

13. Eun Ji Park, Youn Kyoung Cho, Dae Han Kim, Myung-Geun Jeong, Yong Ho Kim*, Young Dok Kim*, "Hydrophobic PDMS coating of mesoporous silica and its use as a pre-concentrating agent of gas analytes" Langmuir (2014) 30, 10256-10262

  https://doi.org/10.1021/la502915r


Abstract

Mesoporous silica with mean pore size of ∼14 nm was coated by polydimethylsiloxane (PDMS) using a thermal deposition method. We showed that the inner walls of pores larger than ∼8 nm can be coated by thin layers of PDMS, and the surfaces consisting of PDMS-coated silica were superhydrophobic, with water contact angles close to 170°. We used the PDMS-coated silica as adsorbents of various gas-phase chemical warfare agent (CWA) simulants. PDMS-coated silica allowed molecular desorption of various CWA simulants even after exposure under highly humid conditions and, therefore, is applicable as an agent for the preconcentration of gas-phase analytes to enhance the sensitivities of various sensors. 

12. Yong-Tae Kim, Seoung-Ki Lee, Kwang-Seop Kim, Yong Ho Kim, Jong-Hyun Ahn, Young-Uk Kwon*, "Uniform growth of high-quality oxide thin films on graphene using a CdSe quantum dot arrays seeding layer" ACS Applied Materials & Interfaces (2014) 6, 13015-13022


Abstract

Graphene displays outstanding properties as an electrode and a semiconducting channel material for transistors; however, the weak interfacial bond between graphene and an inorganic oxide material-based insulator presents a major constraint on these applications. Here, we report a new approach to improving the interface between the two materials using a CdSe quantum dot (QD)-based seeding layer in an inorganic material–graphene junction. CdSe QDs were electrochemically grown on graphene without degrading the properties of the graphene layer. The graphene structure was then used as the electrode in an oxide semiconductor by depositing a zinc oxide thin film onto the graphene coated with a QD seed layer (QD/G). The zinc oxide film adhered strongly to the graphene layer and provided a low contact resistance. A high-k dielectric layer in the form of an HfO2 film, which is an essential element in the fabrication of high-performance graphene-based field effect transistors, was also uniformly formed on the QD/G sheet using atomic layer deposition. The resulting transistors provided a relatively good performance, yielding hole and electron mobilities of 2600 and 2000 cm2/V·s. 

11. Eun Ji Park, Kwang-Dae Kim, Hye Soo Yoon, Myung-Geun Jeong, Dae Han Kim, Dong Chan Lim, Yong Ho Kim*, Young Dok Kim*, "Fabrication of conductive, transparent and superhydrophobic thin films consisting of multi-walled carbon nanotubes" RSC Advances (2014) 4, 30368-30374

  https://doi.org/10.1039/C4RA04272G


Abstract

Polydimethylsiloxane (PDMS) was coated on multi-walled carbon nanotubes (MWCNTs) using a chemical vapour deposition method, and the PDMS-coated MWCNTs were well dispersed in various solvents without additional dispersants. Spin casting of the MWCNT-containing solution on a substrate pre-treated with PDMS-SiO2 nanoparticles resulted in the formation of a uniform thin film. The resulting thin film containing MWCNTs showed high optical transparency, conductivity and superhydrophobicity. We demonstrated that such multifunctional thin films can also be prepared on flexible substrates. 

  https://doi.org/10.1246/cl.140440


Abstract

Annulated borepinol 1 was designed and synthesized. Borepinol 1 exhibited aromaticity that could be controlled by coordination at the boron center. Disrupted coordination by nucleophiles resulted in blue shifts in the UV–vis spectra, and this coordination was affected by the molecular structure of the nucleophiles. Borepinol 1 appeared to selectively bind to dopamine over norepinephrine, which are normally difficult to differentiate. 

  https://doi.org/10.1016/j.synthmet.2014.05.019


Abstract

We report facile synthesis of polydopamine-functionalized graphene oxide/conducting polymer hybrids as an electrode material for supercapacitors. Bio-inspired polydopamine has catechol moieties that can undergo redox transformation, which may result in extra faradic capacitance. Polydopamine-functionalized graphene oxide hybrid materials, which were easily prepared by concomitant dopamine oxidation and slight reduction of graphene oxide, showed enhanced specific capacitance when compared to bare graphene oxide hybrid materials. Although polydopamine layers slightly decreased the conductivity of the hybrid materials, extra redox reactions appeared to contribute more to the overall specific capacitance.


8. Beom Joon Kim, Soong Ho Um, Woo Chul Song, Yong Ho Kim, Moon Sung Kang, Jeong Ho Cho*, "Water-gel for gating graphene transistors" Nano Letters (2014) 14, 2610-2616

  https://doi.org/10.1021/nl500446s


Abstract

Water, the primary electrolyte in biology, attracts significant interest as an electrolyte-type dielectric material for transistors compatible with biological systems. Unfortunately, the fluidic nature and low ionic conductivity of water prevents its practical usage in such applications. Here, we describe the development of a solid state, megahertz-operating, water-based gate dielectric system for operating graphene transistors. The new electrolyte systems were prepared by dissolving metal-substituted DNA polyelectrolytes into water. The addition of these biocompatible polyelectrolytes induced hydrogelation to provide solid-state integrity to the system. They also enhanced the ionic conductivities of the electrolytes, which in turn led to the quick formation of an electric double layer at the graphene/electrolyte interface that is beneficial for modulating currents in graphene transistors at high frequencies. At the optimized conditions, the Na-DNA water-gel-gated flexible transistors and inverters were operated at frequencies above 1 MHz and 100 kHz, respectively.


Before SKKU

7. Yong Ho Kim, Jason E. Donald, Gevorg Grigoryan, George P. Leser , Alexander Y. Fadeev, Robert A. Lamb, and William F. DeGrado, “Capture and Imaging of the Pre-hairpin Intermediate in Viral Membrane Fusion of the Paramyxovirus PIV5”

Proceedings of the National Academy of Sciences (2011) 108, 20992-20997

  https://doi.org/10.1073/pnas.1116034108


Abstract

During cell entry, enveloped viruses fuse their viral membrane with a cellular membrane in a process driven by energetically favorable, large-scale conformational rearrangements of their fusion proteins. Structures of the pre- and postfusion states of the fusion proteins including paramyxovirus PIV5 F and influenza virus hemagglutinin suggest that this occurs via two intermediates. Following formation of an initial complex, the proteins structurally elongate, driving a hydrophobic N-terminal “fusion peptide” away from the protein surface into the target membrane. Paradoxically, this first conformation change moves the viral and cellular bilayers further apart. Next, the fusion proteins form a hairpin that drives the two membranes into close opposition. While the pre- and postfusion hairpin forms have been characterized crystallographically, the transiently extended prehairpin intermediate has not been visualized. To provide evidence for this extended intermediate we measured the interbilayer spacing of a paramyxovirus trapped in the process of fusing with solid-supported bilayers. A gold-labeled peptide that binds the prehairpin intermediate was used to stabilize and specifically image F-proteins in the prehairpin intermediate. The interbilayer spacing is precisely that predicted from a computational model of the prehairpin, providing strong evidence for its structure and functional role. Moreover, the F-proteins in the prehairpin conformation preferentially localize to a patch between the target and viral membranes, consistent with the fact that the formation of the prehairpin is triggered by local contacts between F- and neighboring viral receptor-binding proteins (HN) only when HN binds lipids in its target membrane.


  https://doi.org/10.1128/AAC.05009-11


ABSTRACT

Small arylamide foldamers designed to mimic the amphiphilic nature of antimicrobial peptides (AMPs) have shown potent bactericidal activity against both Gram-negative and Gram-positive strains without many of the drawbacks of natural AMPs. These foldamers were shown to cause large changes in the permeability of the outer membrane of Escherichia coli. They cause more limited permeabilization of the inner membrane which reaches critical levels corresponding with the time required to bring about bacterial cell death. Transcriptional profiling of E. coli treated with sublethal concentrations of the arylamides showed induction of genes related to membrane and oxidative stresses, with some overlap with the effects observed for polymyxin B. Protein secretion into the periplasm and the outer membrane is also compromised, possibly contributing to the lethality of the arylamide compounds. The induction of membrane stress response regulons such as rcs coupled with morphological changes at the membrane observed by electron microscopy suggests that the activity of the arylamides at the membrane represents a significant contribution to their mechanism of action.


5. Gevorg Grigoryan*, Yong Ho Kim*, Rudresh Acharya, Kevin Axelrod, Rishabh M. Jain, Lauren Willis, Marija Drndic, James M. Kikkawa, and William F. DeGrado, “Computational Design of Virus-like Protein Assemblies on Carbon Nanotube Surfaces”

Science (2011) 332, 1071-1076

  https://doi.org/10.1126/science.1198841


Abstract

There is a general need for the engineering of protein-like molecules that organize into geometrically specific superstructures on molecular surfaces, directing further functionalization to create richly textured, multilayered assemblies. Here we describe a computational approach whereby the surface properties and symmetry of a targeted surface define the sequence and superstructure of surface-organizing peptides. Computational design proceeds in a series of steps that encode both surface recognition and favorable intersubunit packing interactions. This procedure is exemplified in the design of peptides that assemble into a tubular structure surrounding single-walled carbon nanotubes (SWNTs). The geometrically defined, virus-like coating created by these peptides converts the smooth surfaces of SWNTs into highly textured assemblies with long-scale order, capable of directing the assembly of gold nanoparticles into helical arrays along the SWNT axis.


4. Ivan V. Korendovych, Yong Ho Kim, Andrew H. Ryan, James D. Lear, William F. DeGrado, and Scott J. Shandler

“Computational Design of a Self-Assembling β-Peptide Oligomer”

Organic Letters (2010) 12, 5142

  https://doi.org/10.1021/ol102092r


Abstract

The first computationally designed self-assembling oligomer consisting of exclusively β-amino acids (βAAs) is presented. The packing of a β-314 helix into coiled-coils of varying stoichiometries as a function of amino acid sequence is examined. β-Peptides with hVal repeating every third residue in the sequence appeared to have a strong propensity to pack into hexameric bundles. The designed sequence was synthesized and characterized with CD spectroscopy, NMR, and analytical ultracentrifugation, suggesting that the peptide adopts a well-folded hexameric structure.


3. Ivan V. Korendovych, Alessandro Senes, Yong Ho Kim, James D. Lear, H. Christopher Fry, Michael J. Therien, J. Kent Blasie, F. Ann Walker, and William F. DeGrado 

“De Novo Design and Molecular Assembly of a Transmembrane Diporphyrin-Binding Protein Complex”

Journal of the American Chemical Society (2010) 132, 15516

  https://doi.org/10.1021/ja107487b


Abstract

The de novo design of membrane proteins remains difficult despite recent advances in understanding the factors that drive membrane protein folding and association. We have designed a membrane protein PRIME (PoRphyrins In MEmbrane) that positions two non-natural iron diphenylporphyrins (FeIIIDPP’s) sufficiently close to provide a multicentered pathway for transmembrane electron transfer. Computational methods previously used for the design of multiporphyrin water-soluble helical proteins were extended to this membrane target. Four helices were arranged in a D2-symmetrical bundle to bind two Fe(II/III) diphenylporphyrins in a bis-His geometry further stabilized by second-shell hydrogen bonds. UV−vis absorbance, CD spectroscopy, analytical ultracentrifugation, redox potentiometry, and EPR demonstrate that PRIME binds the cofactor with high affinity and specificity in the expected geometry.



2. Kwangyeol Lee, Yong Ho Kim, Soo Bong Han, Hongkyu Kang, Soyoung Park, Won Seok Seo, Joon T. Park, Bongsoo Kim, and Sukbok Chang, "Osmium Replica of Mesoporous Silicate MCM-48: Efficient and Reusable Catalyst for Oxidative Cleavage and Dihydroxylation Reactions"

Journal of the American Chemical Society (2003) 125, 6844

  https://doi.org/10.1021/ja034137b


Abstract

A three-dimensional networked osmium nanomaterial (N-Os) was prepared by a thermal decomposition of Os3(CO)12 within mesopores of MCM-48. The novel N-Os species shows high catalytic activity and excellent reusability in the oxidation reactions of unsaturated compounds under mild conditions.


  https://doi.org/10.1021/ja027575b


Abstract

We demonstrate a novel synthetic scheme that can be used to control the crystalline phase and shape of GaP semiconductor nanocrystals. Our study shows that steric effects of surfactant ligands can modulate the crystalline phases and control the shapes of nanocrystals. The shape of the nanocrystals obtained varies from zero-dimensional spheres to one-dimensional rods via controlling the ratio between primary and tertiary alkylamines. III-V semiconductors (in our case:  GaP) under 10 nm in width are first reported, and unique optical properties due to shape anisotropy are also observed.