Spontaneous wrinkle formation on hydrogel surfaces using photoinitiator diffusion from oil-water interface
Eujin Um, Yoon-Kyoung Cho*, Joonwoo Jeong*
Patterning wrinkles on three-dimensional curved or enclosed surfaces can be challenging due to difficulties in application of uniform films and stresses on such structures. In this study, we demonstrate a simple one-step wrinkle-formation method on various hydrogel structures utilizing the oil-water interfaces. By diffusion of the photoinitiator from the oil phase to the prepolymer solution in water through the interface, a characteristic crosslinking gradient is set up in the hydrogel.
 Science, 371, 6526, eabe8678, (2021)
Response to Comment on “Boosted molecular mobility during common chemical reactions”
Huan Wang, Myeonggon Park, Ruoyu Dong, Junyoung Kim, Yoon-Kyoung Cho, Tsvi Tlusty, Steve Granick*
Günther et al. report that their control experiment using randomized magnetic field gradient sequences disagreed with findings we had reported using linear gradients. However, we show that measurements in our laboratory are consistent using both methods.
 ACS Applied Bio Materials, 2021
Advances in Facemasks during the COVID-19 Pandemic Era
Mamata Karmacharya, Sumit Kumar, Oleksandra Gulenko, and Yoon-Kyoung Cho*
The outbreak of coronavirus disease (COVID-19) has transformed the daily lifestyles of people worldwide. COVID-19 was characterized as a pandemic owing to its global spread, and technologies based on engineered materials that help to reduce the spread of infections have been reported. Nanotechnology present in materials with enhanced physicochemical properties and versatile chemical functionalization offer numerous ways to combat the disease. Facemasks are a reliable preventive measure, although they are not 100% effective against viral infections. This study provides a comprehensive review on face masks, from the manufacturing stage to the practical application, and their ability to combat COVID-19. Further, we discuss the impacts of masks on the environment, while considering safe industrial production in the future. We also discuss the available options for the future research directions without negative environmental impacts.
 Nano Letters, 2021
Surface-Textured Mixed-Metal-Oxide Nanocrystals as Efficient Catalysts for ROS Production and Biofilm Eradication
Nitee Kumari, Sumit Kumar, Mamata Karmacharya, Sateesh Dubbu, Taewan Kwon, Varsha Singh, Keun Hwa Chae, Amit Kumar*, Yoon-Kyoung Cho*, and In Su Lee*
Existing antimicrobials cannot function in the complex and stressful chemical conditions found in biofilms, and as a result, they are unable to infiltrate, diffuse into, and eradicate the biofilm and its associated matrix. Here, we introduce mixed-FeCo-oxide-based surface-textured nanostructures (MTex) as highly efficient magneto-catalytic platforms. These systems can produce defensive ROS over a broad pH range and can effectively diffuse into the biofilm and kill the embedded bacteria.
 Nano Letters, 2021
Photoactive Antiviral Face Mask with Self-Sterilization and Reusability
Sumit Kumar, Mamata Karmacharya, Shalik Ram Joshi, Oleksandra Gulenko, Juhee Park, Gun-Ho Kim, and Yoon-Kyoung Cho*
Here, we applied a dual-channel spray-assisted nanocoating hybrid of shellac/copper nanoparticles (CuNPs) to a nonwoven surgical mask, thereby increasing the hydrophobicity of the surface and repelling aqueous droplets. The resulting surface showed outstanding photoactivity (combined photocatalytic and photothermal properties) for antimicrobial action, conferring reusability and self-sterilizing ability to the masks.
 Biomaterials, 265, 120420, (2021)
Adaptive Architecture and Mechanoresponse of Epithelial Cells on a Torus
Sun-Min Yu, Bo Li, François Amblard, Steve Granick, Yoon-Kyoung Cho*
Curvature is a geometric feature widely observed in the epithelia and critical to the performance of fundamental biological functions. In this study, we revealed morphological adaptations and mechanobiological behaviors of epithelial cells on a torus surface with Gaussian curvatures. Our results collectively indicate the ability of epithelial cells to sense Gaussian curvatures and increase the expression of cytoplasmic and nucleus intermediate filaments as a protective measure against curvature-induced mechanical stress.
 J. Extracell Vesicles. 10, e12044 (2020)
Comprehensive evaluation of methods for small extracellular vesicles separation from human plasma, urine and cell culture medium
Liang Dong, Richard C. Zieren, Kengo Horie, Chi‐Ju Kim, Emily Mallick, Yuezhou Jing, Mingxiao Feng, Morgan D. Kuczler, Jordan Green, Sarah R. Amend, Kenneth W. Witwer, Theo M. de Reijke, Yoon‐Kyoung Cho, Kenneth J. Pienta, Wei Xue
One of the challenges that restricts the evolving extracellular vesicle (EV) research field is the lack of a consensus method for EV separation. This may also explain the diversity of the experimental results, as co‐separated soluble proteins and lipoproteins may impede the interpretation of experimental findings. In this study, we comprehensively evaluated the EV yields and sample purities of three most popular EV separation methods, ultracentrifugation, precipitation and size exclusion chromatography combined with ultrafiltration, along with a microfluidic tangential flow filtration device, Exodisc, in three commonly used biological samples, cell culture medium, human urine and plasma.
 Cancers, 12, 10, 2822, (2020)
Detection of EGFR mutations using bronchial washing-derived extracellular vesicles in patients with non-small-cell lung carcinoma
Juhee Park, Chaeeun Lee, Jung Seop Eom, Mi-Hyun Kim *, Yoon-Kyoung Cho *
Here, we demonstrate the clinical potential of BW-derived EVs as a liquid-biopsy sample for prognosis and precision medicine in patients with lung cancer. The acquisition of T790M resistance mutation was detected earlier in BW-derived EVs than in plasma or tissue samples. The longitudinal analysis of BW-derived EVs showed excellent correlation with the disease progression measured by CT images.
 ACS Nano, 14, 11, 14971–14988, (2020)
Three-Dimensional Human Liver-Chip Emulating Pre-Metastatic Niche Formation by Breast Cancer-Derived Extracellular Vesicles
Junyoung Kim, Chaeeun Lee, Inun Kim, Jooyoung Ro, Jungmin Kim, Yoohong Min, Juhee Park, Vijaya Sunkara, Yang-Seok Park, Issac Michael, Young-Ae Kim, Hee Jin Lee, Yoon-Kyoung Cho*
The 3D microfluidic human liver-chip developed in this study demonstrates how breast cancer-derived extracellular vesicles induce the formation of a pre-metastatic niche, promoting the adhesion of circulating tumor cells to a distant organ such as the liver, enabling the investigation of cancer metastasis and a wide range of potential pharmacological therapies.
 Science, 369, 6503, 537-541, (2020)
Boosted molecular mobility during common chemical reactions
Huan Wang, Myeonggon Park, Ruoyu Dong, Junyoung Kim, Yoon-Kyoung Cho, Tsvi Tlusty, Steve Granick*
During a chemical reaction, the reorganization of solvent molecules not directly in contact with reactants and products is normally viewed as a simple diffusion response. Wang et al. studied molecular diffusion in six common reactions—including the copper-catalyzed click reaction and the Diels-Alder reaction—with pulsed-field gradient nuclear magnetic resonance. They observed a boost in mobility relative to Brownian diffusion that was stronger for the catalyzed reactions that were studied. The mobilities for the click reaction were verified with a microfluidic gradient method. They argue that energy release produces transient translational motion of reacting centers that mechanically perturbs solvent molecules.
 Cells, 9, 6, 1434, (2020)
Mechanical Adaptations of Epithelial Cells on Various Protruded Convex Geometries
Sun-Min Yu+, Bo Li+, Steve Granick and Yoon-Kyoung Cho*
Here, we cultured cells on various protruded convex structures such as triangle, square, and circle shape fabricated using two-photon laser lithography and quantitatively analyzed individual cells. We found that intermediate filaments, vimentin, and cytokeratin 8/18, play important roles in the growth and adaptation of epithelial cells by enhancing expression level on convex structure depending on the shape. In addition, microtubule building blocks, α-tubulin, was also responded on geometric structure, which indicates that intermediate filaments and microtubules can cooperatively secure the mechanical stability of epithelial cells on the convex surface. Altogether, the current study will expand our understanding of mechanical adaptations of cells on out-of-plane geometry.
A fidget spinner for the point-of-care diagnosis of urinary tract infection
Issac Michael, Dongyoung Kim, Oleksandra Gulenko , Sumit Kumar, Saravana Kumar , Jothi Clara, Dong Yeob Ki, Juhee Park , Hyun Yong Jeong, Taek Soo Kim, Sunghoon Kwon and Yoon-Kyoung Cho *
Here, we describe a custom-made fidget spinner that rapidly concentrates pathogens in 1-ml samples of undiluted urine by more than 100-fold for the on-device colorimetric detection of bacterial load and pathogen identification. The device enabled the on-site detection of infection with the naked eye within 50 min in urine samples from 39 patients suspected of having a urinary tract infection. We also show that, in 30 clinical samples of urinary tract infection, the device can be used to perform an antimicrobial susceptibility test for the antimicrobial drugs ciprofloxacin and cefazolin within 120 min. The fidget spinner could be used in low-resource settings as an inexpensive handheld point-of-care device for the rapid concentration and detection of pathogens in urine samples.
 Diagnostics, 10, 4, 249, (2020)
Circulating Tumor Cells Enumerated by a Centrifugal Microfluidic Device as a Predictive Marker for Monitoring Ovarian Cancer Treatment: A Pilot Study
Hyera Kim , Minji Lim, Jin Young Kim, So-Jin Shin, Yoon-Kyoung Cho* and Chi Heum Cho*
This pilot study of 13 patients with ovarian cancer aimed to investigate a strategy for the enumeration and detection of CTCs based on a newly-developed centrifugal microfluidic device equipped with a fluid-assisted separation technology (FAST) disc and to demonstrate the correlations among CTC counts from the new device, CA125 concentrations, and clinical course of the disease.
 Angewandte Chemie International Edition, 59, 4, (2020)
Nanocatalosomes as Plasmonic Bilayer Shells with Interlayer Catalytic Hot Nanospaces for Solar‐Light‐Induced Reactions
Amit Kumar, Nitee Kumari, Sateesh Dubbu, Sumit Kumar, Taewan Kwon, Jung Hun Koo, Jongwon Lim, Inki Kim, Yoon-Kyoung Cho, Junsuk Rho, and In Su Lee*
Paramount interest and challenges remain in designing and synthesizing catalysts with nature‐like complexities at few‐nm scale to harness unprecedented functionalities by using sustainable solar light. We introduce “nanocatalosomes”— bio‐inspired bilayer‐vesicular design of nanoreactor with metallic bilayer hollow shell‐in‐shell structure, having numerous controllable confined cavities within few‐nm interlayer space, customizable with different noble metals. This work paves the way towards next‐generation nanoreactors, craftable at few‐nm scale to maximize their functionality and customizable to carry out diverse chemical transformations efficiently with green solar energy.
EV-Ident: Identifying tumor-specific extracellular vesicles by size fractionation and single-vesicle analysis
Dongyoung Kim+, Hyun-Kyung Woo+, Chaeeun Lee, Yoohong Min, Sumit Kumar, Vijaya Sunkara, Hwi-Gyeong Jo, Young Joo Lee, Jisun Kim, Hong Koo Ha, and Yoon-Kyoung Cho*
Here, we introduce EV-Ident for preparation of subpopulations of EVs in three different size fractions: large EVs (EV200 nm; 200−1,000 nm), medium EVs (EV100 nm; 100−200 nm), and small EVs (EV20 nm; 20−100 nm). As a proof-of-concept, we analyzed the presence of human epidermal growth factor receptor 2 (HER2) and prostate-specific membrane antigen (PSMA) in breast cancer and prostate cancer cell-derived EVs, respectively, using three different size fractions at the single-EV level. By reducing the complexity of EV heterogeneity in each size fraction, we found that HER2-positive breast cancer cells showed the greatest expression of HER2 in EV20 nm, whereas PSMA expression was the highest in EV200 nm derived from PSMA expressing prostate cancer cells. This increase in HER2 expression in EV20 nm and PSMA expression in EV200 nm was further confirmed in plasma-derived nanoparticles (PNPs) obtained from breast and prostate cancer patients, respectively.
 Nature Nanotechnology, 15, 4, 1-11, (2020)
Targeted crystallization of mixed-charge nanoparticles in lysosomes induces selective death of cancer cells
Magdalena Borkowska, Marta Siek, Diana V. Kolygina, Yaroslav I. Sobolev, Slawomir Lach, Sumit Kumar, Yoon-Kyoung Cho, Kristiana Kandere-Grzybowska & Bartosz A. Grzybowski
Here, we show that mixed-charge nanoparticles covered with certain ratios of positively and negatively charged ligands can selectively target lysosomes in cancerous cells while exhibiting only marginal cytotoxicity towards normal cells. This selectivity results from distinct pH-dependent aggregation events, starting from the formation of small, endocytosis-prone clusters at cell surfaces and ending with the formation of large and well-ordered nanoparticle assemblies and crystals inside cancer lysosomes. These assemblies cannot be cleared by exocytosis and cause lysosome swelling, which gradually disrupts the integrity of lysosomal membranes, ultimately impairing lysosomal functions and triggering cell death.
 Theranostics, 10, 12, 5181-5194, (2020)
A Lab-on-a-Disc platform enables serial monitoring of Individual CTCs associated with tumor progression during EGFR-targeted therapy for patients with NSCLC
Minji Lim+, Juhee Park+, Alarice C. Lowe, Hyoung-oh Jeong, Semin Lee, Hee Chul Park, Kyusang Lee, Gwang Ha Kim, Mi-Hyun Kim*, and Yoon-Kyoung Cho*
The change ratio of the CTC counts was associated with tumor response, detected by CT scan, while the baseline CTC counts did not show association with progression-free survival or overall survival. We achieved a 100% concordance rate for the detection of EGFR mutation, including the emergence of T790M, between tumor tissue and CTCs. More importantly, our data revealed the importance of the analysis of the epithelial/mesenchymal signature of individual pretreatment CTCs to predict drug responsiveness in patients. The fluid-assisted separation technology disc platform enables serial monitoring of CTC counts, DNA mutations, as well as unbiased molecular characterization of individual CTCs associated with tumor progression during targeted therapy.
 BJU International, 126, 1, 191-201, (2020)
The combination of size‐based separation and selection‐free technology provides higher circulating tumor cells detection sensitivity than either method alone in patients with metastatic prostate cancer
Liang Dong, Zhongyuan Zhang, Kimberly Smith, Morgan Kuczler, Diane Reyes, Sarah R. Amend, Yoon‐Kyoung Cho, Wei Xue*, and Kenneth J. Pienta*
Here, we investigate the CTC capture abilities of two technologies that are not dependent on cell‐surface marker expression: a selection‐free platform, the AccuCyte®‐CyteFinder® system (Rarecyte) and a size‐based platform, the fluid‐assisted separation technology (FAST). The combination of the two systems to more completely assess CTCs was investigated.
 Lab Chip, 20, 5, 949-957, (2020)
Fully automated platelet isolation on a centrifugal microfluidic device for molecular diagnostics
Chi-Ju Kim+, Dong Yeob Ki+, Juhee Park, Vijaya Sunkara, Tae-Hyeong Kim, YooHong Min and Yoon-Kyoung Cho*
Herein, we describe a fully automated lab-on-a-disc-based method of platelet isolation from a small volume of blood (<1 mL). This method provides higher yields (>4 folds) and purity (>99%) and lower platelet activation than the conventional method. Moreover, it was also superior in the detection of platelet-related RNAs CD41, PF4, and P2Y12 due to lower contamination with white blood cells.
 Nano Letters, 20, 1, 441-448, (2020)
Near-Field Electrospinning for Three-Dimensional Stacked Nanoarchitectures with High Aspect Ratios
Yang-Seok Park+, Junyoung Kim+, Jung Min Oh, Seungyoung Park, Seungse Cho, Hyunhyub Ko, Yoon-Kyoung Cho*
Herein, we report on a direct-write 3D NFES technique to construct self-aligned, template-free, 3D stacked nanoarchitectures by simply adding salt to the polymer solution. Numerical simulations suggested that the electric field could be tuned to achieve self-aligned nanofibers by adjusting the conductivity of the polymer solution. We demonstrate the 3D printing of nanoskyscrapers with various designs, such as curved “nanowall arrays”, nano “jungle gyms,” and “nanobridges”. Further, we present an application of the 3D stacked nanofiber arrays by preparing transparent and flexible polydimethylsiloxane films embedded with Ag-sputtered nanowalls as 3D nanoelectrodes. The conductivity of the nanoelectrodes can be precisely tuned by adjusting the number of 3D printed layers, without sacrificing transmittance. The current NFES approach provides a simple, reliable route to build 3D stacked nanoarchitectures with high-aspect ratios for potential applications in smart materials, energy devices, and biomedical applications.