• Membrane Journal
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• v.25 no.1
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• pp.48-59
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• 2015

This paper reports a fabrication of poly(L-lactic acid) (PLLA) scaffold membranes through phase separation process using pure and mixed solvents. Chloroform and 1,4-dioxane were used as pure solvents and mixed solvents were obtained by mixing the pure solvents together. Morphologies, mechanical properties and mass transfer characteristics of the scaffold membranes were investigated through SEM, stress-strain test and glucose diffusion test. Scaffold membranes from the solution with pure chloroform showed solid-wall pore structure. In contrast, nano-fibrous membranes were fabricated from the solution with pure 1,4-dioxane. In case of mixed solvents, the scaffold membranes showed various structures with changing composition of the solvents. When 1,4-dioxane content was lower than 20 wt% in the solvent, scaffold membrane showed solid-wall pore structure. When the content was 20 wt%, scaffold membranes with macropores with the maximum size of $100{\mu}m$ was obtained. In the concentration range of 1,4-dioxane over 25 wt%, the scaffold membranes showed nano-fibrous structures. In this range, the fibers showed different diameters with changing composition of the solvent. The minimum fiber diameter was about $15{\mu}m$, when 1,4-dioxane composition was 80 wt%. These results indicate that the composition of the solvent showed a significant effect on the structure of scaffold membrane.

• Membrane Journal
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• v.24 no.2
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• pp.113-122
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• 2014

Porous poly(L-lactic acid)(PLLA) scaffold membranes were prepared via. phase separation process. Chloroform, dichloromethane and 1,4-dioxane were used as solvent and, ethyl alcohol was used as non-solvent. Morphologies, mechanical properties and mass transfer characteristics of the scaffold membranes were investigated through SEM, stress-strain test and glucose diffusion test. The scaffold membranes obtained from the casting solutions with chloroform and with dichloromethane showed similar morphologies. They showed sponge-like porous structure with the pore size in the range of $3-10{\mu}m$ and, their porosities were in 50-80% range. Using 1,4-dioxane as solvent, nano-fibrous scaffold membranes with porosities over 80% were fabricated. When the polymer content in the solution with 1,4-dioxane was lowered to 4%, highly porous, macroporous and nano-fibrous scaffold membranes were obtained. The size of the macropore was tens of the microns and the porosity was around 90%. These results indicate that the solvent has significant effect on the scaffold membrane structure and, that scaffold membranes with various structures can be fabricated through phase separation method by choosing solvent and by controlling polymer concentration in the casting solution.

• Journal of Korean Dental Science
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• v.4 no.2
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• pp.39-45
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• 2011

Purpose: The goal of this research is to find the role of collagen membrane, which can reduce physical damage, as a scaffold for possible alternative to the corticotomy which causes Regional Acceleratory Phenomenon (RAP). Materials and Methods: The experiments were carried out on 12 New Zealand white rabbits, approximately 3.5 kg in bodyweight. We made an incision on the skin of the mandibular border and applied 37% phosphoric acid and collagen membrane to the mandibular bone surface of the first group (experimental group), and only phosphoric acid to the second group (control group). After 3 days, 1 week, and 2 weeks, 4 rabbits each were sacrificed and specimens were obtained. Each specimen was stained by H&E and Tartrate-resistant acid phosphatase (TRAP), and histological changes were observed by light microscope. Results: The demineralization of the experimental group was weak compared to the control group. It also showed a gradual increase of demineralization (after 3 days, 1 week, and 2 weeks) and the control group showed more extensive demineralization than the experimental group. Conclusion: This study demonstrates the amount of demineralization as a result of using phosphoric acid, and as time went by, demineralization increased. The absorbable collagen membrane was used as a scaffold to increase bone demineralization effect and prevent dispersion to adjacent tissues, but rather the amount of bone demineralization decreased. Therefore, the role of collagen membrane as a scaffold for RAP was weak.

• Journal of Periodontal and Implant Science
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• v.49 no.4
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• pp.258-267
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• 2019

Purpose: Increased bone regeneration has been achieved through the use of stem cells in combination with graft material. However, the survival of transplanted stem cells remains a major concern. The purpose of this study was to evaluate the viability of transplanted mesenchymal stem cells (MSCs) at an early time point (24 hours) based on the type and form of the scaffold used, including type I collagen membrane and synthetic bone. Methods: The stem cells were obtained from the periosteum of the otherwise healthy dental patients. Four symmetrical circular defects measuring 6 mm in diameter were made in New Zealand white rabbits using a trephine drill. The defects were grafted with 1) synthetic bone (${\beta}$-tricalcium phosphate/hydroxyapatite [${\beta}-TCP/HA$]) and $1{\times}10^5MSCs$, 2) collagen membrane and $1{\times}10^5MSCs$, 3) ${\beta}-TCP/HA+collagen$ membrane and $1{\times}10^5MSCs$, or 4) ${\beta}-TCP/HA$, a chipped collagen membrane and $1{\times}10^5MSCs$. Cellular viability and the cell migration rate were analyzed. Results: Cells were easily separated from the collagen membrane, but not from synthetic bone. The number of stem cells attached to synthetic bone in groups 1, 3, and 4 seemed to be similar. Cellular viability in group 2 was significantly higher than in the other groups (P<0.05). The cell migration rate was highest in group 2, but this difference was not statistically significant (P>0.05). Conclusions: This study showed that stem cells can be applied when a membrane is used as a scaffold under no or minimal pressure. When space maintenance is needed, stem cells can be loaded onto synthetic bone with a chipped membrane to enhance the survival rate.

• Molecules and Cells
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• v.37 no.12
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• pp.881-887
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• 2014

Cell proliferation is tightly controlled by the cell-cycle regulatory proteins, primarily by cyclins and cyclin-dependent kinases (CDKs) in the $G_1$ phase. The ankyrin repeat-rich membrane spanning (ARMS) scaffold protein, also known as kinase D-interacting substrate of 220 kDa (Kidins 220), has been previously identified as a prominent downstream target of neurotrophin and ephrin receptors. Many studies have reported that ARMS/Kidins220 acts as a major signaling platform in organizing the signaling complex to regulate various cellular responses in the nervous and vascular systems. However, the role of ARMS/Kidins220 in cell proliferation and cell-cycle progression has never been investigated. Here we report that knockdown of ARMS/Kidins220 inhibits mouse neuroblastoma cell proliferation by inducing slowdown of cell cycle in the $G_1$ phase. This effect is mediated by the upregulation of a CDK inhibitor p21, which causes the decrease in cyclin D1 and CDK4 protein levels and subsequent reduction of pRb hyperphosphorylation. Our results suggest a new role of ARMS/Kidins220 as a signaling platform to regulate tumor cell proliferation in response to the extracellular stimuli.

• Journal of Biosystems Engineering
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• v.32 no.1 s.120
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• pp.57-62
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• 2007

The objectives of this study were to prepare a new artificial eardrum patch using water-insoluble chitosan for healing the tympanic membrane perforations and to investigate biomechanical properties and cyotoxicity of the chitosan patch scaffold (CPS). Tensile strength and elongation at the rupture point of CPSs were 2.49-74.05 MPa and 0.11-107.06%, respectively. As the biomechanical properties or CPSs varied with the concentration of chitosan and glycerol, the proper conditions for the CPS were found out. SEM analysis showed very smooth and uniform surface of CPSs without pores at x1000. The result of MTT test showed that CPSs had no cytotoxicity.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.251-252
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• 2007

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• Membrane Journal
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• v.11 no.1
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• pp.29-37
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• 2001

본 논문은 인공 진피와 조직공학용 scaffold로 이용하기 위해 다공성 membrane로서 gelatin-based sponge의 효율성을 연구하였다. 불용성의 다공성 membrane은 1-ethyl-(3-3dimethylaminopropyl)carbodiimide(EDC)로 가교하여 제조하였다. Fourier-transformed infrared (FT-IR) spectroscopy, scanning electron microscopy(SEM) 그리고 Instron analysis로 다공성 membrane의 특성을 조사하였다. 다공성 membrane은 용적당 큰 표면적을 제공하는 micro porous한 구조를 가지고 있다. Gelatin/hyaluronic acid (HA) membrane의 공경크기는 40~200$\mu\textrm{m}$이다. HA의 첨가는 다공성 membrane의 기계적 강도와 세포부착능력에 영향을 미쳤다. Gelatin/HA 다공성 membrane의 압축강도는 collagen과 비슷하며, 세포배양과 인공진피 transplantation에 있어서의 충분한 기계적 강도를 가지고 있다. Fibroblasts를 함유한 진피기질을 제조하기 위해 직경 8mm의 다공성 membran에 4$\times$10(sup)5cells/membrane의 세포밀도로 fibroblast를 배양하였다. GH91 porous membrane에서의 fibroblast 부착성은 GH55 porous membrane에서보다 우수하였다. 삼차원 구조의 gelatin/HA membrane matrix에서의 fibroblast의 배양은 생체내 조건과 유사한 생리적 환경을 제공하였다.

• Archives of Plastic Surgery
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• v.48 no.4
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• pp.448-456
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• 2021

Background Locoregional stem cell delivery is very important for increasing the efficiency of cell therapy. Amnisite BA (Amnisite) is a freeze-dried amniotic membrane harvested from bovine placenta. The objective of this study was to investigate the retention of cells of the stromal vascular fraction (SVF) on Amnisite and to determine the effects of cell-loaded Amnisite in a porcine radiation-induced chronic wound model. Methods Initially, experiments were conducted to find the most suitable hydration and incubation conditions for the attachment of SVF cells extracted from pig fat to Amnisite. Before seeding, SVFs were labeled with PKH67. The SVF cell-loaded Amnisite (group S), Amnisite only (group A), and polyurethane foam (group C) were applied to treat radiation-induced chronic wounds in a porcine model. Biopsy was performed at 10, 14, and 21 days post-operation for histological analysis. Results Retaining the SVF on Amnisite required 30 minutes for hydration and 1 hour for incubation. A PKH67 fluorescence study showed that Amnisite successfully delivered the SVF to the wounds. In histological analysis, group S showed increased re-epithelialization and revascularization with decreased inflammation at 10 days post-operation. Conclusions SVFs had acceptable adherence on hydrated Amnisite, with successful cell delivery to a radiation-induced chronic wound model.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.1
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• pp.17-24
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• 2004

The purpose of this study was to evaluate the stability and efficacy of biologic membrane made of freeze-dried cartilage as a barrier to facilitate guided bone regeneration in experimental non-healing bone defects in the rat mandible. Nine adult Sprague-Dawley rats (400-500g) were used in experiment. 5.0mm in diameter were created on the mandibular angle area by means of slow-speed trephine drill. In microscopic examination, dynamic immature bone forming at 2 weeks and its calcification at 4 weeks were observed. The membrane made of lyophilized cartilage taken from human costal cartilage seems to be very effective for guided bone regeneration as a biologic membrane and the scaffold for attachment of cells or local drug delivery system of growth factor, which may meet the ideal requirement of a barrier membrane and graft materials.