• Macromolecular Research
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• v.15 no.4
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• pp.370-378
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• 2007

Mechanical stimulation is known to activate several cellular signal transduction pathways, leading to the induction of signaling molecules and extracellular matrix (ECM) proteins, thereby modulating cellular activities, such as proliferation and survival. In this study, primary human dermal fibroblasts (HDFs) were seeded onto chitosan-based scaffolds, and then cultured for 3 weeks in a bioreactor under a cyclic strain of 1 Hz frequency. Compared to control samples cultured under static conditions, the application of a cyclic strain stimulated the proliferation of HDFs in I week, and by week 3 the thickness of the cell/scaffold composites increased 1.56 fold. Moreover, immunohistochemical staining of the culture media obtained from the cell/scaffold samples subjected to the cyclic strain, revealed increases in the expression and secretion of ECM proteins, such as fibronectin and collagen. These results suggest that the preconditioning of cell/scaffold composites with a cyclic strain may enhance the proliferation of HDFs, and even facilitate integration of the engineered artificial dermal tissue into the host graft site.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.225-225
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• 2005

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.131-132
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• 2005

• Archives of Plastic Surgery
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• v.35 no.2
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• pp.127-133
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• 2008

Purpose: The purpose of this study is to evaluate the remodeling process of the various skin substitutes in 4th and 6th weeks following the transplantation when transplanted onto nude mice. Methods: Three types of artificial skin substitutes, such as PLGA scaffold with keratinocyte sheets(group 1), acellular human dermis($Surederm^{(TM)}$) and keratinocyte sheet(group 2), bioengineered skin($Neoderm^{(TM)}$)(group 3), were applied to the wound on nude mice. All mice were killed in 2, 4 weeks and/or 6 weeks after grafting and tissue samples were harvested from the back of mice. The changes in wound size, degree of angiogenesis, formation of basement membrane and epidermis, density of collagen fibers and neural restoration were examined. Results: There was no significant changes in wound size among the three groups. However, the size of wound decreased in the non-substituted group due to contracture. Degree of angiogenesis and systhesis of collagen or neurofilaments were mostly increased in bioengineered skin($Neoderm^{(TM)}$)(group 3), followed by acellular human dermis($Surederm^{(TM)}$) and keratinocyte sheet(group 2), PLGA scaffold with keratinocyte sheets (group 1). However, group 3 and group 2 showed similar thickness of basement membrane and epidermis. Conclusion: We found that degree of angiogenesis, formation of basement membrane and skin appendages, density of collagen fibers and neurofilaments can be the categories to evaluate the success of artificial skin substitution in early stages.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.300-301
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• 2003

• Archives of Plastic Surgery
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• v.35 no.1
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• pp.7-12
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• 2008

Purpose: Since the report of artificial dermis manufacturing method using collagen by Yannas in 1980, collagen has been effectively used as dermal substitute with its merits such as, lower antigeneicity, controllable biodegradation rate, and minimal inflammatory cytotoxic properties in the dermal tissue engineering field. However, weak mechanical durability was the main drawback of collagen dermal substitute. To improve its stability, mechanical or chemical cross-linking was used. Despite of such process, its clinical use was restricted due to weak durability. To improve the durability of collagen matrix, we designed elastin-incorporated collagen matrix and compared its durability with conventional collagen matrix. Methods: 15mm diameter with 4mm thick collagen dermal matrix was made according to Yannas protocol by mixing 0.5% bovine collagen and chondroitin-6-sulfate followed by degassing, freeze drying, dehydrodermal cross-linking and chemical cross-linking procedure. In elastin incorporated collagen matrix, same procedure was performed by mixing elastin to previous collagen matrix in 4:1 ratio(collagen 80% elastin 20%). In comparison of the two dermal matrix in vitro tests, matrix contracture rate, strain, tensile strength, was measured and stiffness was calculated from comparative analysis. Results: In terms of matrix contracture, the elastin-incorperated added collagen dermis matrix showed 1.2 times more contraction compared to conventional collagen matrix. However, tensile strength showed 1.6 times and stiffness showed 1.6 times increase in elastin-incorporated matrix. Conclusion: Elastin incorperated collagen matrix manufactured by our team showed increased durability due to improvement in tensile strength and stiffness compared to previous collagen matrix($Integra^{(R)}$).

• Journal of Biomedical Engineering Research
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• v.14 no.1
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• pp.51-62
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• 1993

An experimental study was performed for the preparation of living skin-equivalent by the using collagen gel contraction with human fibroblasts as neodermls and cultured human keratinocytes as neoderm is . The results were as follows ; 1) The rate of collagen gel contraction was dependent on the number of fibroblasts into the lattice and collagen contraction was progressed according to the increment of the number of the cells. 2) The rate of collagen gel contraction was progressed according to the decrement of the contraction of the collagen. 3) The rate of gel contraction was progressed according to the increment of serum concentration in the fixed concentration of the fibroblasts and collagen. 4) The lattice contraction was decreased according to the increment of the population doublings of the fibroblasts. 5) Macroscopically, the artificial dermis was gray white in color and tissue-like consistency and elas- ticity. 6) Microscopically, three dimensionally contracted artificial dermis showed more dense fibroblasts and its newly formed collagen fibrils in the matrix than one dimensionally contracted one. 7) Finally prepared skin-equivalent showed good attachment of living stratified keratinocytes to the dermal equivalent microscopically. It has been proposed that newly formed skin-equivalent is suitable for the graft of extensively and deeply burned patients. Shortening of the manufacturing period of skin-equivalent and development of conservation technique as a readily usable state are to be solved for our ongoing works.

• Archives of Plastic Surgery
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• v.39 no.4
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• pp.390-396
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• 2012

Background The radial forearm osteocutaneous free flap is considered to be the standard technique for penile construction. One year after their operation, most patients experience a softened phallus, so that they suffer from difficulties in sexual intercourse. In this report, we present our experience with phalloplasty by radial forearm osteocutaneous free flap, as well as an evaluation of the etiology and treatment of the softened phallus. Methods Between March 2005 and February 2010, 58 patients underwent phalloplasty by radial forearm osteocutaneous free flap. Most of their neophallus had been softened subjectively and among them, 12 patients who wanted correction were investigated. We performed repetitive fat injection, artificial dermis grafting, silicone rod insertion, and rib bone with cartilaginous tip graft. Physical examination, plain radiograph, computed tomography, bone scintigraphy, and satisfaction scores were investigated. Results Most of the participants' penises have been softened after phalloplasty, and the skin elasticity had been also decreased. On plain radiograph, the distal end of the bone was self-rounded; however, the bone shape of the neophallus had no significant interval changes or resorption. Computed tomography showed equivocal density of cortical bone. On bone scintigraphy, the bone metabolism was active at 3 months postoperatively, and remained active 9 years postoperatively. Conclusions The use of a rib bone with cartilaginous tip graft could be an option for improvement of the softened phallus. Silicon rod insertion is also worth considering for rigidity of the softened phallus. Decreased rigidity due to soft tissue atrophy could be alleviated with repeated fat injection and artificial dermis grafting.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.100.2-101
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• 2003

To satisfy the increasing medical demanding especially for sever burn patients to regenerate full thickness wound cure, this study developed dermis with gelatin based scaffold and perform the biocompatibility tests. To prepare scaffold 30% of gelatin was mixed with sieved salt and dried in the mold to shape then, cross linked with a water-soluble cross-linker, EDAC. Preparing the cell for seeding from a rabbit skin, the fibroblast and keratinocyte were successfully isolated and cultured in vitro. After cell and scaffold were ready, the fibroblast was seeded to the scaffold (∼10$\^$6/ cell/cm ) for preparing dermis and keratinocyte was cultured until forming the sheet. (omitted)

• Applied Microscopy
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• v.52
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• pp.3.1-3.8
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• 2022

Our purpose in this study is to analyze the microstructural characteristics and constituent elements of inorganic substances added to the yellow ink and red ink pigments used in permanent makeup. We observed the microstructural properties of inorganic pigments added to the ink using a scanning electron microscopy (SEM) and analyzed the constituent elements of the inorganic pigment particles using an energy dispersive X-ray spectroscopy (EDX). In red wine-colored ink, cubic titanium dioxide with a diameter of 110 to 200 nm was the major component, and rod-shaped iron oxide was rarely observed. Most of the ingredients of taupe yellow ink were rod-shaped yellow iron oxide, and a small amount of cubic titanium dioxide was observed. Red wine-colored ink and taupe yellow ink contained lumps composed of titanium dioxide particles. In red wine-colored ink, lumps were formed by agglomeration. However, we observed that the surface of the lump composed of titanium dioxide in the taupe yellow ink had a smooth surface caused by external physical compression. The titanium dioxide particle mass which found in taupe yellow ink in this study is an artificial product. When this mass accumulates in the dermis, it may cause a color mismatch. Therefore, permanent makeup using fine pigments should be free of foreign substances that may cause trouble in the skin. In addition, there is a need to improve the quality of the ink so that the required color can be safe and long lasting in the dermis.