• Archives of Plastic Surgery
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• 제32권5호
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• pp.599-606
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• 2005

Clinical application of the cartilage formed by tissue engineering is of no practical use due to the failure of long-term structural integrity maintenance. One of the important factors for integrity maintenance is the biomaterial for a scaffold. The purpose of this study is to evaluate the difference between polylactic-co-glycolic acids (PLGA) and chitosan as scaffolds. Human auricular chondrocytes were isolated, cultured, and seeded on the scaffolds, which were implanted in the back of nude mice. Eight animals were sacrificed at 4, 8, 12, 16, and 24 weeks after implantation respectively. In gross examination and histological findings, the volume of chondrocyte-PLGA complexes was decreased rapidly. The volume of chondrocyte-chitosan complexes was well maintained with a slow decrease rate. The expression of type II collagen protein detected by immunohistochemistry and western blots became weaker with time in the chondrocyte-PLGA complexes. However, the expression in the chondrocyte-chitosan complexes was strong for the whole period. Collagen type II gene expressions using RT-PCR showed a similar pattern. In conclusion, these results suggest that chitosan is a superior scaffold in cartilage tissue engineering in terms of structural integrity maintenance. It is expected that chitosan scaffold may become one of the most useful scaffolds for cartilage tissue engineering.

• 한국기계가공학회지
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• 제21권4호
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• pp.70-76
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• 2022

Calcium-phosphate-based bioceramics are promising biomaterials for scaffolds because they can assist in bone regeneration. In this study, a laser sintering deposition system was developed, and 3D hydroxyapatite (HA) scaffolds were fabricated. The main process conditions of the HA scaffolds were laser power, table velocity, and laser focal distance. As the laser power increased, the line width, line height, and layer thickness also increased. Further, the line width, line height, and layer thickness decreased as the table velocity increased. As the laser focal distance increased, the line width increased, but the line height and layer thickness decreased. The fabricated green scaffolds were sintered at 1050 ℃ and 1150 ℃. The sintered scaffolds had a uniform and continuous interconnected shape, with pore sizes ranging from 850 to 950 ㎛ having 53% porosity. The compressive strength of the scaffolds decreased from 0.72 MPa (1050 ℃) to 0.53 MPa (1150 ℃). The biocompatibility of the scaffolds was investigated by analyzing the adhesion of osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The results indicate that the scaffold sintered at 1050 ℃ had good mechanical and biological properties compared to that at 1150 ℃.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.518-523
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• 2004

PLGA was suggested. Under various conditions, their diameters and porosity as well as mechanical strength were evaluated. In addition to those, cell(chondrocyte) proliferation and formation of extracelluar matrices were also investigated along with the conventional membrane type PLGA scaffolds for the potential use in tissue engineering. As conclusions, this type of scaffold showed a potential of application to tissue engineering in view of mechanical stability as well as cellular responses.

• 폴리머
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• 제29권2호
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• pp.198-203
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• 2005

용융 압출 발포에 의하여 폴리락틱산(PLLA) 지지체를 제조하고 발포 조건이 지지체의 구조와 기계적 특성에 미치는 영향을 살펴보고 이를 염 추출법에 의하여 제조된 지지체와 비교하였다. 발포제를 함유한 PLLA 용융체가 압출기 및 다이에서 체류하는 시간이 발포제의 무게를 최대로 감소시키는 시간과 일치하여야 최적의 PLLA 지지체의 구조를 얻을 수 있음을 확인하였다. PLLA지지체의 구조를 유지하기 위해서는 발포제의 함량을 $10\;wt\%$ 이하로 조절해야 하며 PLLA 지지체의 다공도는 PLLA의 압출기에서의 체류시간에 가장 큰 영향을 받음을 알 수 있었다. 용융 압출 발포에 의하여 얻어진 지지체는 일반적으로 염 추출법에 의하여 제조된 지지체보다 다소 낮은 다공도를 갖지만 발포 조건의 조절에 의하여 적절한 다공 크기와 다공의 연결성을 가지며 동시에 우수한 기계적 특성을 가져 경조직 재생(hard tissue regeneration)용으로 사용이 가능할 것으로 사료된다.

• 한국기계가공학회지
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• 제17권1호
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• pp.108-115
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• 2018

In bone tissue engineering, polycaprolactone (PCL) is one of the most widely used biomaterials to manufacture scaffolds as a synthetic polymer with biodegradability and biocompatibility. The polymer deposition system (PDS) with four axis heads, which can dispense bio-polymers, has been used in scaffold fabrication for tissue engineering applications. A dual-head deposition technology of PDS is an effective technique to fabricate 3D scaffolds. The electrospinning technology has been widely used to fabricate porous and highly interconnected polymer fibers. Thus, PDS can fabricate nanofiber-combined hybrid scaffolds using fused deposition modeling (FDM) and electrospinning methods. This study aims to fabricate nanofiber-combined scaffolds with uniform nanofibers using PDS. The PCL nanofibers were fabricated and evaluated according to the fabrication process parameters. PCL nanofibers were successfully fabricated when the applied voltage, tip-to-collector distance, flow rate, and solution concentration were 5 kV, 1 cm, 0.1 ml/h, and 8 wt%, respectively. The cell proliferation was evaluated according to the electrospinning time. Scanning electron microscopy was used to acquire images of the cross-sectioned hybrid scaffolds. The cell proliferation test of the PCL and nanofiber-combined hybrid scaffolds was performed using a CCK-8 assay according to the electrospinning time. The result of in-vitro cell proliferation using osteosarcoma MG-63 cells shows that the hybrid scaffold has good potential for bone regeneration.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권5호
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• pp.405-418
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• 2007

Mesenchymal stem cells(MSCs) have been though to be multipotent cells that can replicate that have the potential to differentiate into lineages of mesenchymal tissue including the bone, cartilage, fat, tendon, muscle, and marrow stroma. Especially, scaffolds to support cell-based tissue engineering are critical determinants of clinical efforts to regenerate and repair the body. Selection of a matrix carrier imvolves consideration of the matrix's role as a scaffold for physical support and host tissue integration as well as its ability to support of synergize the osteoinductive program of the implanted mesenchymal stem cell. The aim of this study is to evaluate the effect of autobone and Bio-$Oss^{(R)}$ to adherent mesenchymal stem cells as scaffolds on sinus augmentation with fibrin glue mixture in a rabbit model. 16 New Zealand White rabbits were divided randomly into 4 groups based on their time of sacrifice(1, 2, 4 and 8 weeks). First, mesenchymal stem cells were isolated from iliac crest marrow of rabbits and expanded in vitro. Cell culture was performed in accordance with the technique described by Tsutsumi et al. In the present study, the animals were sacrificed at 1, 2, 4 and 8 weeks after transplantation, and the bone formation ability of each sides was evaluated clinically, radiologically, histologically and histomorphologically. According to the histological observations, autobone scaffolds group showed integrated graft bone with host bone from sinus wall. At 2 and 4 weeks, it showed active newly formed bone and neovascularization. At 8 weeks, lamellae bone was observed in sinus graft material area. Radiologically, autobone with stem cell showed more radiopaque than Bio-$Oss^{(R)}$ scaffolds group. there were significant differences in bone volume between 4 and 8 weeks(p<0.05).

• 폴리머
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• 제35권6호
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• pp.499-504
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• 2011

본 연구팀은 탈미네랄화 골분(DBP)이라는 천연재료를 졸(sol)화시켜 poly(lactide-co-glycolide) (PLGA)에 함침시킨 지지체를 개발하였다. DBP를 함침시킨 PLGA 지지체 상의 세포증식과 모폴로지를 평가하기 위해 MTT 분석과 SEM을 측정하였다. 또한 sGAG와 콜라겐 함량 측정과 파종된 연골 세포의 표현형 유지에 미치는 영향을 확인하였다. 그 결과 PLGA에 DBP를 함침시킨 지지체가 PLGA 지지체보다 높은 세포 증식률을 보였다. 또한 파종된 연골세포의 표현형 유지에도 긍정적인 영향을 미치는 것을 확인하였다. 이번 연구 결과를 토대로 PLGA에 DBP를 이용한 용액을 함침시킴으로써 DBP내의 성장인자와의 상호작용을 통해 연골세포의 성장에 긍정적 영향을 미쳐 안정되게 연골을 조직화할 수 있는 연골조직공학 지지체로 적합할 것으로 예상된다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.268-268
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• 2006

Due to their multipotency, stem cells can differentiate into a variety of specialized cell types, such as chondrocytes, osteoblasts, myoblasts, and nerve cells. As an alternative to mature tissue cells, stem cells are of importance in tissue engineering and regenerative medicine. Since interactions between scaffold and cells play an important role in the tissue development in vitro, synthetic oligopeptides have been immobilized onto polymeric scaffolds to improve specific cell attachment and even to stimulate cell differentiation. In this study, chondrogenic differentiation of stem cells was evaluated using surface-modified PLLA scaffolds, i.e., either hydrophilic acrylic acid (AA)-grafted PLLA or RGD-immobilized one. Porous PLLA scaffolds were prepared using a gas foaming method, followed by plasma treatment and subsequent grafting of AA to introduce a hydrophilicity (PLLA-PAA). This was further processed to fix RGD peptide to make an RGD-immobilized scaffold (PLLA-PAA-RGD). Stem cells were seeded at $1{\times}10^{6}$ cells per scaffold and the cell-PLLA constructs were cultured for up to 4 weeks in the chondrogenic medium. Using these surface-modified scaffolds, adhesion, proliferation, and chondrogenic differentiation of stem cells were evaluated. The surface of PLLA scaffolds turned hydrophilic (water contact angle, 45 degrees) with both plasma treatment and AA grafting. The hydrophilicity of RGD-immobilized surface was not significantly altered. Cell proliferation rate on the either PLLA-PAA or PLLA-PAA-RGD surface was obviously improved, especially with the RGD-immobilized one as compared to the control PLLA one. Chondrogenic differentiation was clearly identified with Safranin O staining of GAG in the AA- or RGD-grafted PLLA substrates. This study demonstrated that modified polymer surfaces may provide better environment for chondrogenesis of stem cells.

• 폴리머
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• 제25권4호
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• pp.476-485
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• 2001

본 연구에서는 고분자 지지체를 만든 후 약물을 흡수시켜 방출 특성을 검토하는 기존의 방법에서 나타나는 초기 과다 방출이라는 단점을 보완하고 장기간에 걸친 약물방출이 가능한 고분자 지지체를 구축하기 위해 광반응 관능기를 갖는 히아루론산과 sodium alginate 유도체로 세포의 성장을 촉진하는 약물을 함입한 미립자를 만들고 이를 성형가공한 고분자 지지체를 제작하여 약물 방출 특성을 검토하였다. 이러한 방법으로 만들어진 지지체는 초기 방출이 억제되고 오랜 기간 동안 지속적으로 약물을 서서히 방출하였으며, 뿐만 아니라 천연고분자가 갖는 생체내 분해 특성으로 인하여 일정한 기간 동안 형태를 유지하며 지지체로 기능을 한 이후 분해되어 재생된 조직이 손상조직과 대체 가능하므로, 세포의 성장과 분화를 유도하는 손상조직 대체용 고분자 지지체 본연의 목적을 달성할 수 있을 것으로 기대된다.

• Journal of Veterinary Science
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• 제19권6호
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• pp.735-743
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• 2018

We investigated the effect of transforming growth factor beta 1 ($TGF-{\beta}1$) on equine hyaluronan synthase 2 (HAS2) gene expression and hyaluronan (HA) synthesis in culture models of articular chondrocytes. Equine chondrocytes were treated with $TGF-{\beta}1$ at different concentrations and times in monolayer cultures. In three-dimensional cultures, chondrocyte-seeded gelatin scaffolds were cultured in chondrogenic media containing 10 ng/mL of $TGF-{\beta}1$. The amounts of HA in conditioned media and in scaffolds were determined by enzyme-linked immunosorbent assays. HAS2 mRNA expression was analyzed by semi-quantitative reverse transcription polymerase chain reaction. The uronic acid content and DNA content of the scaffolds were measured by using colorimetric and Hoechst 33258 assays, respectively. Cell proliferation was evaluated by using the alamarBlue assay. Scanning electron microscopy (SEM), histology, and immunohistochemistry were used for microscopic analysis of the samples. The upregulation of HAS2 mRNA levels by $TGF-{\beta}1$ stimulation was dose and time dependent. $TGF-{\beta}1$ was shown to enhance HA and uronic acid content in the scaffolds. Cell proliferation and DNA content were significantly lower in $TGF-{\beta}1$ treatments. SEM and histological results revealed the formation of a cartilaginous-like extracellular matrix in the $TGF-{\beta}1$-treated scaffolds. Together, our results suggest that $TGF-{\beta}1$ has a stimulatory effect on equine chondrocytes, enhancing HA synthesis and promoting cartilage matrix generation.