Dong-Wook Han - Academia.edu (original) (raw)

Papers by Dong-Wook Han

Key Engineering Materials

b-glucan, an immunomodulator, can selectively enhance the immunobiological activities of neutroph... more b-glucan, an immunomodulator, can selectively enhance the immunobiological activities of neutrophils and macrophages without stimulating proinflammatory cytokine production. Biologic response modifiers, like beta-glucan, will modulate immunity, modify neoplastic disease and increase resistance to microbial challenge. Therefore, beta-glucan polymers can be applied in bone induction and regeneration model and have a possibility of association with bone morphogenetic protein (BMP) because of tissue-regenerative and antimicrobial effects of those polymers. In this report, we studied an E. coli expression system for BMP-7 production and the biological activities of b-glucan associated with BMP-7. The proliferation of MC3T3-E1 osteoblastic cells was enhanced by treatment with Aureobasidium b-glucan, while neither mushroom b-glucan nor barley b-glucan increased the cell proliferation. Mushroom b-glucan alone or associated with BMP-7 increased alkaline phosphatase (ALP) activity of MC3T3-E1...

Regenerative Biomaterials, 2017

Carbon, 2015

Osteoprogenitor cells, known as preosteoblasts, that arise from mesenchymal stem cells in the bon... more Osteoprogenitor cells, known as preosteoblasts, that arise from mesenchymal stem cells in the bone marrow are types of cells that work in the growth or repair of bones. These cells possess the prominent potential to differentiate toward the osteogenic lineage, and therefore offer promising opportunities for bone tissue engineering and regenerative therapy. However, to fully exploit the application of osteoprogenitor cells in bone regeneration, it is critical to develop biochemical, physical or pharmaceutical factors that can precisely control their osteogenic differentiation. In this study, we hypothesized that reduced graphene oxide (rGO) and hydroxyapatite (HAp) composites could synergistically enhance the osteogenic differentiation of preosteoblasts. Without interference with the proliferation of MC3T3-E1 preosteoblasts, rGO/HAp composites synergistically enhanced the osteogenic differentiation of the preosteoblasts, which had been confirmed by determining alkaline phosphatase activity and mineralization of calcium and phosphate as early and late stage markers of osteogenic differentiation. This osteogenic activity mediated by rGO/HAp composites was further accelerated under osteogenic culture conditions. It is suggested that rGO/HAp hybrid composites can serve as biocompatible, transferable, and implantable scaffolds for bone regeneration because these graphene-based composite materials have the potential to promote spontaneous osteogenesis in the absence of any osteogenic factors.

Key Engineering Materials, 2007

In this study, such behaviors of vascular smooth muscle cells (VSMCs), as proliferation and migra... more In this study, such behaviors of vascular smooth muscle cells (VSMCs), as proliferation and migration, with serum stimulation were investigated onto (−)-epigallocatechin-3-O-gallate (EGCG)-blended poly(L-lactide-co-ε-caprolactone, PLCL) copolymers (EGCG-b PLCL). VSMCs were primarily cultured from rat aorta, and EGCG-b PLCL films were fabricated by mixing PLCL with EGCG. The proliferation of VSMCs cultured onto EGCG-b PLCL film was significantly suppressed in spite of serum induction. Moreover, recovery of denuded area by VSMCs receiving conditioned media obtained from EGCG-b films was completely inhibited, whereas VSMCs onto intact films migrated into denuded area in response to serum showing essentially complete recovery. These results suggest that inhibition in the behaviors of serum-stimulated VSMCs may be mediated through the anti-proliferative effects of EGCG released from polymer films, and EGCG-b polymers can be applied for fabricating an EGCG-eluting vascular stent.

Biomaterials research, 2016

Hydrogels can serve as three-dimensional (3D) scaffolds for cell culture and be readily injected ... more Hydrogels can serve as three-dimensional (3D) scaffolds for cell culture and be readily injected into the body. Recent advances in the image technology for 3D scaffolds like hydrogels have attracted considerable attention to overcome the drawbacks of ordinary imaging technologies such as optical and fluorescence microscopy. Multiphoton microscopy (MPM) is an effective method based on the excitation of two-photons. In the present study, C2C12 myoblasts differentiated in 3D gelatin hydroxyphenylpropionic acid (GHPA) hydrogels were imaged by using a custom-built multiphoton excitation fluorescence microscopy to compare the difference in the imaging capacity between conventional microscopy and MPM. The physicochemical properties of GHPA hydrogels were characterized by using scanning electron microscopy and Fourier-transform infrared spectroscopy. In addition, the cell viability and proliferation of C2C12 myoblasts cultured in the GHPA hydrogels were analyzed by using Live/Dead Cell and ...

Scientific reports, Jan 21, 2015

Recently, graphene-based nanomaterials, in the form of two dimensional substrates or three dimens... more Recently, graphene-based nanomaterials, in the form of two dimensional substrates or three dimensional foams, have attracted considerable attention as bioactive scaffolds to promote the differentiation of various stem cells towards specific lineages. On the other hand, the potential advantages of using graphene-based hybrid composites directly as factors inducing cellular differentiation as well as tissue regeneration are unclear. This study examined whether nanocomposites of reduced graphene oxide (rGO) and hydroxyapatite (HAp) (rGO/HAp NCs) could enhance the osteogenesis of MC3T3-E1 preosteoblasts and promote new bone formation. When combined with HAp, rGO synergistically promoted the spontaneous osteodifferentiation of MC3T3-E1 cells without hindering their proliferation. This enhanced osteogenesis was corroborated from determination of alkaline phosphatase activity as early stage markers of osteodifferentiation and mineralization of calcium and phosphate as late stage markers. I...

Biomaterials research, 2014

M13 bacteriophages can be readily fabricated as nanofibers due to non-toxic bacterial virus with ... more M13 bacteriophages can be readily fabricated as nanofibers due to non-toxic bacterial virus with a nanofiber-like shape. In the present study, we prepared hybrid nanofiber matrices composed of poly(lactic-co-glycolic acid, PLGA) and M13 bacteriophages which were genetically modified to display the RGD peptide on their surface (RGD-M13 phage). The surface morphology and chemical composition of hybrid nanofiber matrices were characterized by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. Immunofluorescence staining was conducted to investigate the existence of M13 bacteriophages in RGD-M13 phage/PLGA hybrid nanofibers. In addition, the attachment and proliferation of three different types of fibroblasts on RGD-M13 phage/PLGA nanofiber matrices were evaluated to explore how fibroblasts interact with these matrices. SEM images showed that RGD-M13 phage/PLGA hybrid matrices had the non-woven porous structure, quite similar to that of natural extracellular matric...

Biomaterials Research, 2015

Yonsei Medical Journal, 1999

Journal of the Korean Physical Society, 2015

Biochemistry & Pharmacology: Open Access, 2014

Journal of microbiology and biotechnology, 2008

The inactivating efficiency of alternating high-voltage pulsed (AHVP) current was investigated in... more The inactivating efficiency of alternating high-voltage pulsed (AHVP) current was investigated in brine (20 w/v% NaCl) and saline (0.9 w/v% NaCl) inoculated with 1x 10(7) cells/ml of Listeria monocytogenes. AHVP current at 12 V with 1 pulse completely inactivated L. monocytogenes in brine within 3 ms, while the bacteria in saline were fully inactivated by 10-pulsed electric treatment at 12 V within the same time. Electron microscopic observation demonstrated substantial structural damage of electrically treated L. monocytogenes in brine. These results suggest that AHVP treatment would be effective for the rapid and complete inactivation of L. monocytogenes in brine or saline solution.

Artificial Organs, 2013

Epigallocatechin-3-O-gallate (EGCG) is a major polyphenolic compound in green tea. It has been kn... more Epigallocatechin-3-O-gallate (EGCG) is a major polyphenolic compound in green tea. It has been known that EGCG regulates the secretion of cytokines and the activation of skin cells during wound healing. In this study, various concentrations of EGCG were added to the electrospun membranes composed of poly (lactic-co-glycolic acid) (PLGA), and its healing effects on full-thickness wounds created in nude mice were investigated. The electrospun membranes containing 5 wt% EGCG (5EGCG/PLGA membrane) exhibited cytotoxicity in human dermal fibroblasts (HDFs) as HDF morphologies were transformed on them. In the animal study, cell infiltration of mice treated with electrospun membranes containing 1 wt% EGCG (1EGCG/PLGA membrane) significantly increased after 2 weeks. The immunoreactivity of Ki-67 (re-epithelialization at the wound site) and CD 31 (formation of blood vessels) also increased in the mice treated with 1EGCG/PLGA membranes in comparison with the mice treated with PLGA membranes. These results suggest that 1EGCG/PLGA can enhance wound healing in full thickness by accelerating cell infiltration, re-epithelialization, and angiogenesis.

Tissue Engineering and Regenerative Medicine, 2014

ABSTRACT

Sensors and Actuators B: Chemical, 2015

ABSTRACT We developed a capacitance sensor with parallel plate geometry to measure epithermal gro... more ABSTRACT We developed a capacitance sensor with parallel plate geometry to measure epithermal growth factor receptor (EGFR) expression levels on cell membrane in real-time. We first proved correlations between capacitance changes and cell numbers settled down between electrodes, and then observed capacitance changes elicited by interactions between EGFR on membrane and EGF proteins in real time. Consequently, we confirmed that the EGFR expression levels of varied typed cells were successfully quantified. This approach can effectively distinguish differences of EGFR levels of cancer cells and normal cells in real-time. Also, up to 600% sensitivity enhancements and around 2.2 h on average sensing time saving were achieved by using the capacitance sensor over a conventional immunoassay technique. Such a capacitance biosensor can be extended to broad fields where the receptor–antibody reactions, the receptor–virus reactions or DNA hybridizations are involved.

Wound Repair and Regeneration, 2008

Oxidative Medicine and Cellular Longevity, 2012