• 대한기계학회논문집A
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• 제38권8호
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• pp.875-880
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• 2014

최근에, 3 차원 인공지지체와 나노섬유는 골 조직 재생을 위해 개발되고 있다. 본 연구에서는, 나노-마이크로 정밀 분사 시스템을 이용하여 하이브리드 인공지지체를 제작하였다. 하이브리드 인공지지체는 마이크로 인공지지체와 나노섬유가 결합하여 제작되었으며, 마이크로 인공지지체와 나노섬유를 얻기 위해 자유 형상 제작 기술과 전기방사 기법이 사용되었다. 마이크로 인공지지체는 정밀한 공극을 고려하여 CAD/CAM 데이터 따라 자유 형상 제작 기술에 의해 제작되었으며, 제작 공정은 $100^{\circ}C$의 온도, 평균 650 kPa의 압력, 그리고 250 mm/sec의 Z 축 이송속도가 적용되었다. 그리고 전기방사법을 통하여 나노섬유를 제작함에 있어서 본 시스템에 적용한 공정 조건은, 5 kV의 전압, 0.1 ml/min의 유량, 그리고 1 mm의 노즐 팁과 콜렉터와의 거리로 설정하였다. 제작된 하이브리드 인공지지체는 MG-63 세포를 이용하여 세포 증식 실험을 진행하였다.

• 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.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.51.2-51.2
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• 2011

A novel electrospun nanofiber membrane was fabricated using combined poly (vinylphosphonic acid) (PVPA) and polyvinyl alcohol (PVA) intended for bone tissue engineering applications. PVPA is a proton-conducting polymer used as primer for bone implants and dental cements to prevent corrosion and brush abrasion. The phosphonate groups of PVPA have the ability to crosslink and attach itself to the hydroxyapatite surface facilitating faster integration of the biomaterial to the bone matrix. PVA was combined with PVPA to provide hydrophilicity, biocompatibility and improve its spinnability. To improve its mechanical strength, PVPA/PVA and neat PVA mixtures were combined to produce a multilayer scaffold. The physical and chemical properties of the of the fabricated matrix was investigated by SEM and TEM morphological analyses, tensile strength test, XRD, FT-IR spectra, swelling behavior and biodegradation rates, porosity and contact angle measurements. Biocompatibility was also examined in vitro by cytotoxicity and cell proliferation studies with MTT assay and cell adhesion behavior by SEM and confocal microscopy.

• Carbon letters
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• 제13권3호
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• pp.139-150
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• 2012

Poly-L-lactic acid (PLLA), PLLA/hydroxyapatite (HA), PLLA/multiwalled carbon nanotubes (MWNTs)/HA, PLLA/trifluoroethanol (TFE), PLLA/gelatin, and carbon nanofibers (CNFs)/${\beta}$-tricalcium phosphate (${\beta}$-TCP) composite membranes (scaffolds) were fabricated by electrospinning and their morphologies, and mechanical properties were characterized for use in bone tissue regeneration/guided tissue regeneration. MWNTs and HA nanoparticles were well distributed in the membranes and the degradation characteristics were improved. PLLA/MWNTs/HA membranes enhanced the adhesion and proliferation of periodontal ligament cells (PDLCs) by 30% and inhibited the adhesion of gingival epithelial cells by 30%. Osteoblast-like MG-63 cells on the randomly fiber oriented PLLA/TEF membrane showed irregular forms, while the cells exhibited shuttle-like shapes on the parallel fiber oriented membrane. Classical supersaturated simulated body fluids were modified by $CO_2$ bubbling and applied to promote the biomineralization of the PLLA/gelatin membrane; this resulted in predictions of bone bonding bioactivity of the substrates. The ${\beta}$-TCP membranes exhibit good biocompatibility, have an effect on PDLC growth comparable to that of pure CNF membrane, and can be applied as scaffolds for bone tissue regeneration.

• 폴리머
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• 제37권5호
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• pp.632-637
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• 2013

늑연골세포는 초기 증식능력이 관절연골세포보다 우수하며, 또한 세포 채취에 용이하다는 장점이 있어, 관절연골의 대안으로 사용된다. FDA의 승인을 받은 합성고분자인 폴리락산-글리콜산 공중합체(PLGA)는 조직공학적 생체재료로 사용되고 있으나, 세포 부착률이 낮고, 염증반응을 야기시킨다고 보고되고 있다. 본 연구에서는 세포의 증식에 영향을 주며 염증반응이 감소된다고 보고된 탈미네랄골분(DBP)을 이용하여, 함량별 DBP/PLGA를 제조한 뒤, 세포를 파종하여 연구를 실시하였다. 세포의 부착 및 증식률을 측정하기 위하여 세포 파종한 후 MTT와 SEM 분석을 수행하였으며, DBP가 세포외 기질 형성에 미치는 영향을 확인하고자 글리코스아미노글라이칸(sGAG)과 콜라겐 함량을 측정하였다. 생체 내 외 환경에서 세포의 부착과 증식에 미치는 영향을 관찰하기 위해 연구를 진행하여, PLGA 지지체보다 DBP/PLGA 지지체가 세포의 성장과 증식에 영향을 주는 것을 확인하였으며, DBP의 함량이 증가할수록 효과가 좋은 것으로 나타났다.

• 대한구강악안면임플란트학회지
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• 제18권2호
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• pp.120-138
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• 2014

Purpose: The purpose of this study was to review the outcomes of a series of studies on tissue regeneration conducted in multiple institutions including the Department of Periodontology, College of Dentistry, Yonsei University. Materials and Methods: Studies were performed divided into the following three subjects; 1) Development of three-dimensional nano-hydroxyapatite (n-HA) scaffold for facilitating drug release and cell adhesion. 2) Synergistic effects of bone marrow-derived mesenchymal stem cells (BMMSC) application simultaneously with platelet-rich plasma (PRP) on HA scaffolds. 3) The efficacy of silk scaffolds coated with n-HA. Also, all results were analyzed by subjects. Results: Hollow hydroxyapatite spherical granules were found to be a useful tool for the drug release and avidin-biotin binding system for cell attachment. Also, BMMSC simultaneously with PRP applied in an animal bone defect model was seen to be more synergistic than in the control group. But, the efficacy of periodontal ligament cells and dental pulp cells with silk scaffolds could not be confirmed in the initial phase of bone healing. Conclusion: The ideal combination of three elements of tissue engineering-scaffolds, cells and signaling molecules could be substantiated due to further investigations with the potentials and limitations of the suggested list of studies.

• Journal of Periodontal and Implant Science
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• 제38권sup2호
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• pp.355-362
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• 2008

Purpose: The carrier for the delivery of bone morphogenetic proteins(BMPs) should also serve as a scaffold for new bone growth. In addition, predictable bone formation in terms of the volume and shape should be guaranteed. This study evaluated the ectopic bone formation of recombinant human BMP-2(rhBMP-2) using a micro macroporous biphasic calcium phosphate (MBCP: mixture of ${\beta}TCP$ and HA) block as a carrier in a rat subcutaneous assay model. Materials and Methods: Subcutaneous pockets were created on the back of 40 male Sprague-Dawley rats. In the pockets, rhBMP-2/MBCP and MBCP alone were implanted. The blocks were evaluated by histological and histometric parameters after a healing interval of 2 weeks (each 10 rats; MBCP and rhBMP-2/MBCP) or 8 weeks (each 10 rats; MBCP and rhBMP-2/MBCP). Results: The shape and volume of the block was maintained stable over the healing period. No histological bone forming activity was observed in the MBCP alone sites after 2 weeks and there was minimal new bone formation at 8 weeks. In the rhBMP-2/MBCP sites, new bone formation was evident in the macropores of the block. The new bone area at 8 weeks was greater than at 2 weeks. There was a further increase in the quantity of new bone with the more advanced stage of remodeling. Conclusions: A MBCP block could serve as a carrier system for predictable bone tissue engineering using rhBMPs.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.567-577
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• 2006

Background Several bone grafting materials have been used in sinus augmentation procedures. Macroporous Biphasic Calcium Phosphate($MBCP^{TM}$) consists of the mixture of 60% HA and 40% ${\beta}-TCP$. Therefore, it can provide good scaffold for the new bone to grow owing to HA, in the other hand, it can have bioactivity for bone remodeling owing to ${\beta}-TCP$. The purpose of this study was to evaluate bone formation following maxillary sinus augmentation using $MBCP^{TM}$ by means of histologic analysis. Material and Method $MBCP^{TM}$ was placed as a primary bone substitute for maxillary sinus augmentation. Three patients were selected after evalaution of their medical dental examination. $MBCP^{TM}$ only, $MBCP^{TM}$ combined with Irradicated cancellous bone and $MBCP^{TM}$ combined with autogenous bone were used for each patient. After about eight months, bone biopsies were harvested for histologic evaluation and fixtures installed. Results Eight months after surgery we observed new vital bone surrounding $MBCP^{TM}$ particle and the amount of new bone was about 30% even though there were discrepancies between specimens. This case report documents that $MBCP^{TM}$ when used as a grafting material for sinus floor augmentation whether combined other bone graft material or not, may lead to the predictable results for dental implants on posterior maxillary area with insufficient vertical height for fixture installation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.219-220
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• 2007

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권5호
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• pp.420-424
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• 2011

Allomatrix (Wright Medical Tech, Inc., Arlington, Tenn, USA), is a newly designed, injectable putty with a reliable demineralized bone matrix (DBM), derived from human bone. The compound contains 86% DBM and other bone growth factors such as bone morphogenic protein (BMP)-2, BMP-4, insulin-like growth factor (IGF)-1, and transforming growth factor (TGF)-${\beta}1$. It has excellent osteoinduction abilities. In addition, DBM is known to have osteoconduction capacity as a scaffold due to its collagen matrix. This product contains a powder, which is a mix of DBM and surgical grade calcium sulfate as a carrier. A practitioner can blend the powder with calcium sulfate solution, making a putty-type material which has the advantages of ease of handling, better fixation, and no need for a membrane, because it can function as membrane itself. This study reports the clinical and radiographic results of various guided bone regeneration cases using Allomatrix, demonstrating its strong potential as a graft material.