Park, Sungjo

Abstract Background: With the enormous increment of globalization and global warming, it is expected that the number of newly evolved infectious diseases will continue to increase. To prevent damage due to these infections, the development of a diagnostic method for detecting a virus with high sensitivity in a short time is highly desired. In this study, we have developed a high-sensitivity and high-accuracy disposable electrode and evaluated it for several target viruses. Results: Conductive silicon rubber (CSR) was used to fabricate a disposable sensing matrix composed of nitrogen and sulfur-codoped graphene quantum dots (N,S-GQDs) and a gold-polyaniline nanocomposite (AuNP-PAni). A specific anti-white spot syndrome virus (WSSV) antibody was conjugated to the surface of this nanocomposite, which wassuccessfully applied for the detection of WSSV over a wide linear range of 1.45 × 10 2 to 1.45 × 10⁵ DNA copies/ml, with a detection limit as low as 48.4 DNA copies/ml. Conclusion: The engineered sensor electrode can retain the detection activity for up to 5 weeks, a vital long-term stability requirement for disposable sensing applications. This is the first demonstration of the detection of WSSV by ananofabricated sensing electrode with high sensitivity, selectivity, and stability, providing a potential diagnostic tool to monitor WSSV in the aquaculture industry.

Abstract Background: With the enormous increment of globalization and global warming, it is expected that the number of newly evolved infectious diseases will continue to increase. To prevent damage due to these infections, the development of a diagnostic method for detecting a virus with high sensitivity in a short time is highly desired. In this study, we have developed a disposable electrode with high-sensitivity and accuracy to evaluate its performances for several target viruses.Results: Conductive silicon rubber (CSR) was used to fabricate a disposable sensing matrix composed of nitrogen and sulfur-co-doped graphene quantum dots (N,S-GQDs) and a gold-polyaniline nanocomposite (AuNP-PAni). A specific anti-white spot syndrome virus (WSSV) antibody was conjugated to the surface of this nanocomposite, which was successfully applied for the detection of WSSV over a wide linear range of concentration from 1.45 × 102 to 1.45 × 10⁵ DNA copies/ml, with a detection limit as low as 48.4 DNA copies/ml.Conclusion: The engineered sensor electrode can retain the detection activity up to 5 weeks, to confirm its long-term stability, required for disposable sensing applications. This is the first demonstration of the detection of WSSV by a nanofabricated sensing electrode with high sensitivity, selectivity, and stability, providing as a potential diagnostic tool to monitor WSSV in the aquaculture industry.

Abstract Background: With the enormous increment of globalization and global warming, it is expected that the number of newly evolved infectious diseases will continue to increase. To prevent damage due to these infections, the development of a diagnostic method for detecting a virus with high sensitivity in a short time is highly desired. In this study, we have developed a high-sensitivity and high-accuracy disposable electrode and evaluated it for several target viruses.Results: Conductive silicon rubber (CSR) was used to fabricate a disposable sensing matrix composed of nitrogen and sulfur-codoped graphene quantum dots (N,S-GQDs) and a gold-polyaniline nanocomposite (AuNP-PAni). A specific anti-white spot syndrome virus (WSSV) antibody was conjugated to the surface of this nanocomposite, which was successfully applied for the detection of WSSV over a wide linear range of 1.45 × 102 to 1.45 × 10⁵ DNA copies/ml, with a detection limit as low as 48.4 DNA copies/ml.Conclusion: The engineered sensor electrode can retain the detection activity for up to 5 weeks, a vital long-term stability requirement for disposable sensing applications. This is the first demonstration of the detection of WSSV by a nanofabricated sensing electrode with high sensitivity, selectivity, and stability, providing a potential diagnostic tool to monitor WSSV in the aquaculture industry.

AbstractConduits that promote nerve regeneration are currently of great medical concern, particularly when gaps exist between nerve endings. To address this issue, our laboratory previously developed a nerve conduit from biodegradable poly(caprolactone fumarate) (PCLF) that supports peripheral nerve regeneration. The present study improves upon this work by further developing an electrically conductive, positively charged PCLF scaffold through the incorporation of graphene, carbon nanotubes (CNTs), and [2‐(methacryloyloxy)ethyl]trimethylammonium chloride (MTAC) (PCLF–Graphene–CNT–MTAC) using ultraviolet (UV) induced photocrosslinking. Scanning electron microscopy, transmission electron microscopy, and atomic force microscopy were used to assess the incorporation of CNTs and graphene into PCLF–Graphene–CNT–MTAC scaffolds, which displayed enhanced surface roughness and reduced electrochemical impedance when compared to neat PCLF. Scaffolds with these surface modifications also showed improved growth and differentiation of rat pheochromocytoma 12 cells in vitro, with enhanced cell growth, neurite extension, and cellular migration. Furthermore, an increased number of neurite protrusions were observed when the conduit was electrically stimulated. These results show that the electrically conductive PCLF–Graphene–CNT–MTAC nerve scaffolds presented here support the cellular behaviors that are critical for nerve regeneration, ultimately making this material an attractive candidate for regenerative medicine applications.

Abstract Incorporation of hydroxyapatite (HA) into polymer networks is a promising strategy to enhance the mechanical properties and osteoinductivity of the composite scaffolds for bone tissue engineering. In this study, we designed a group of nanocomposite scaffolds based on cross‐linkable poly(propylene fumarate) (PPF) and 30 wt % strontium‐hydroxyapatite (Sr‐HA) nanoparticles. Four different Sr contents [Sr:(Sr + Ca), molar ratio] in the Sr‐HA particles were studied: 0% (HA), 5% (Sr5‐HA), 10% (Sr10‐HA), and 20% (Sr20‐HA). Two‐dimensional (2D) disks were prepared using a thermal crosslinking method. The structure and surface morphology of different Sr‐HA and PPF/Sr‐HA composites were characterized using scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). To detect cellular responses in vitro, MC3T3‐E1 cells were seeded and cultured on the different PPF/Sr‐HA composite disks. Cell morphology after 24 h and 5 days were imaged using Live/Dead live cell staining and SEM, respectively. Cell proliferation was quantified using an MTS assay at 1, 4, and 7 days. Osteogenic differentiation of the cells was examined by alkaline phosphatase (ALP) staining at 10 days and quantified using ALP activity and osteocalcin assays at 7, 14, and 21 days. The sizes of the HA, Sr5‐HA, Sr10‐HA, and Sr20‐HA particles were mainly between 10 × 20 nm and 10 × 250 nm, and these nanoparticles were dispersed or clustered in the composite scaffolds. in vitro cell studies showed that the PPF/Sr10‐HA scaffold was significantly better than the other three groups (PPF/HA, PPF/Sr5‐HA, and PPF/Sr20‐HA) in supporting MC3T3‐E1 cell adhesion, proliferation, and differentiation. PPF/Sr10‐HA may, therefore, serve as a promising scaffold material for bone tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 631–642, 2019.

Biomimetic biomaterials require good biocompatibility and bioactivity to serve as appropriate scaffolds for tissue engineering applications.

Chemically crosslinking GOa and CNTpega followed by in situ reduction fabricated a conductive rGOa–CNTpega–OPF hydrogel that strongly stimulated neurite growth.

Acetyl‐CoA carboxylase 2 (ACC2) is an isoform of ACC functioning as a negative regulator of fatty acid β‐oxidation. Spot14, a thyroid hormone responsive protein, and Mig12, a Spot14 paralog, have recently been identified as regulators of fatty acid synthesis targeting ACC1, a distinctive subtype of ACC. Here, we examined whether Spot14/Mig12 modulates ACC2. Nanoscale protein topography mapped putative protein–protein interactions between purified human Spot14/Mig12 and ACC2, validated by functional assays. Human ACC2 displayed consistent enzymatic activity, and homogeneous particle distribution was probed by atomic force microscopy. Citrate‐induced polymerization and enzymatic activity of ACC2 were restrained by the addition of the recombinant Spot14/Mig12 heterocomplex but only partially by the oligo‐heterocomplex, demonstrating that the heterocomplex is a designated metabolic inhibitor of human ACC2. Moreover, Spot14/Mig12 demonstrated a sequestering role preventing an initial ACC2 nucleation step during filamentous polymer formation. Thus, the Spot14/Mig12 heterocomplex controls human ACC2 polymerization and catalytic function, emerging as a previously unrecognized molecular regulator in catalytic lipid metabolism. © 2013 The Authors. Journal of Molecular Recognition published by John Wiley & Sons, Ltd.