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정윤기,박기동,박귀덕,한동근,Joung, Yoon-Ki,Park, Ki-Dong,Park, Kwi-Deok,Han, Dong-Keun 대한의용생체공학회 2008 의공학회지 Vol.29 No.4
In tissue engineering, scaffolds play an important role in the growth of cells to 3-D organs or tissues. For the success of tissue engineering, they should be mimicked to meet the requirements of natural extracellular matrix (ECM) in the body, such as mechanical properties, adhesiveness, porosity, biodegradability, and growth factor release, etc. Contrary to other materials, polymeric materials are adequate to engineer scaffolds for tissue engineering because controlling the structure and the ratio of components and designing various shapes and size are possible. In this review, the importance, major characteristics, processes, and recent examples of polymeric scaffolds for tissue engineering applications are discussed.
표면개질에 의해 하이드록시아파타이트가 형성된 티타늄에 대한 특성 및 세포 점착
배순언 ( Soon Eon Bae ),박귀덕 ( Kwi Deok Park ),한동근 ( Dong Keun Han ) 한국조직공학과 재생의학회 2011 조직공학과 재생의학 Vol.8 No.2s
Titanium (Ti) and its alloys were frequently used in many surgical and dental implants because of its good biocompatibility and mechanical properties. However, they often lack a direct bonding with bone after implantation. In order to enhance a new bone formation, surface composition and roughness of metal implants need to be carefully controlled. In this study, Ti implant discs were modified by using two oxidative methods; chemical (NH4OH/H2O2/H2O) and physical (O2 plasma) treatments. Hydroxyapatite (HA) deposition on the surface of oxidative Ti samples was then induced in simulated body fluid (SBF) for 7 days in vitro. When the surface morphology of HA-formed Ti was determined using SEM, the surface layer was covered with nano-scaled HA particles. The chemically treated HA-Ti specimens provided preosteoblast with more favorable surface environment in up-regulating cell proliferation and alkaline phosphatase (ALP) activity. The present data indicated that the surface treatment of Ti could have a significant impact on HA formation, preosteoblast proliferation, and differentiation.
세포점착성 PLLA-PAA-RGD 지지체를 이용한 연골세포 증식시 생물반응기의 효과
양희석 ( Hee Seok Yang ),박귀덕 ( Kwi Deok Park ),김재진 ( Jae Jin Kim ),김병수 ( Byung Soo Kim ),한동근 ( Dong Keun Han ) 한국조직공학·재생의학회 2008 조직공학과 재생의학 Vol.5 No.3
Porous poly(L-lactic acid)(PLLA) scaffolds were prepared and then grafted with acrylic acid(AAc) using in situ direct plasma treatment to obtain hydrophilic PLLA-PAA. The obtained PLLA-PAAc was coupled with Gly- Arg-Asp-Gly(GRGD) as a ligand peptide to get cell-adhesive PLLA-PAAc-RGD. The prepared AA-grafted and RGD-immobilized PLLA films were confirmed from various surface analyses. Chondrocyte isolated from rabbit knee articular cartilages was passaged twice before cell seeding on the PLLA scaffolds. Once seeded on either PLLA scaffolds, they were placed in a multi-functional bioreactor system and an intermittent hydrodynamic pressure(IHP) was applied in 3 bars, while turned on for 2 min and off for 28 min during 3-weeks culture. Chondrocyte adhesion increased with time and the order of the adhesion was PLLA control<PLLA-PAAc<PLLA-PAAc-RGD. In addition, the contents of total collagen and glycosaminoglycans(GAG) increased in dynamic culture system as compared with static one. This suggests that the bioreactor may significantly enhance the adhesion and proliferation of chondrocytes irrespective of kinds of PLLA scaffolds.
생분해성 고분자 스텐트를 위한 나선형 구조의 팽창력 연구
박철호(Chul Ho Park),박가람(Ga Ram Park),최지연(Ji Yeon Choi),박귀덕(Kwi Deok Park),한동근(Dong Keun Han) 한국고분자학회 2011 폴리머 Vol.35 No.3
생분해성 고분자 스텐트는 상대적으로 향상된 생체적합성 및 낮은 부작용으로 기존의 비분해성 금속 스텐트를 대체하기 위해 이슈가 되고 있다. 기본적으로 모든 스텐트들은 확장된 혈관의 직경을 유지하기 위해 요구되는 기계적 강도, 특히 압축력 또는 팽창력을 가져야만 한다. 따라서, 본 연구는 나선형 구조체를 제안하였으며, 측면 압축력과 구조적 인자들과의 관련성에 집중하였다. 실린더의 구조체와 달리, 나선형 구조체의 팽창력은 두께와 길이에 1차승으로 비례하고, 직경은 1.6지승의 반비례 관계를 가지고 있었다. 하지만 간극 사이의 거리는 하중과 관련성을 보이지 않았다. 본 연구에서 얻어진 이러한 함수는 임상 적용 스텐트를 설계하고 제조하는데 기초적인 정보를 제공할 수 있다. Biodegradable polymeric stents have been issued to replace the existing non-degradable metal stents due to relatively improved biocompatibility and low side effects. Fundamentally, all the stents must possess the desired mechanism strength, especially, compression or radial force to maintain the diameters of expanded vessels. Therefore, this study suggests a helical structure and focused on the relation between the lateral compression and structural factors. Unlike a cylindrical model, the radial force of the helical model is proportional to the thickness and the length to the power of one, whereas the diameter to the power of 1.6. The function obtained from these results might provide the fundamental information to design and prepare the stent for clinical applications.
표면개질된 생분해성 PLLA 필름 및 지지체의 연골세포와 조골세포 점착거동
한동근(Dong Keun Han),최지연(Ji Yeon Choi),정현정(Hyun Jung Jung),박방주(Bang Ju Park),정윤기(Yoon Ki Joung),박귀덕(Kwi Deok Park) 한국고분자학회 2012 폴리머 Vol.36 No.3
Poly(L-lactic acid)(PLLA) 고분자 필름 및 지지체의 세포 친화성을 향상시키기 위하여 산소 플라즈마 처리 후 카복실기를 함유한 아크릴산(AA)을 in situ 그래프트시켰다. Stimulated body fluid(SBF) 용액에 15일간 담지시 킨 후 hydroxyapatite(HA)를 형성시킨 시료와 phosphate-buffered saline(PBS), fetal bovine serum(FBS), 식염수 및 세포 배양용 배지에 담지시킨 다음 PLLA 시료 표면의 접촉각을 비교해 본 결과, HA 표면이 가장 낮은 접촉각 을 나타내었다. 또한 연골세포와 조골세포는 HA 표면 위에서 높은 점착과 성장을 보였으며 연골세포가 HA에 많 은 영향을 받는 것으로 확인되었다. 조골세포의 경우 HA 표면 이외에도 FBS나 세포 배양배지에 담지된 표면에서 도 높은 세포 증식을 보였다. 더욱이 필름형태보다는 3차원 입체 구조의 다공성 지지체에서 연골세포와 조골세포 의 점착과 세포 증식이 향상됨도 확인할 수 있었다. 이러한 표면개질된 PLLA는 조직공학적으로 연골이나 뼈 재생 을 위한 유-무기 하이브리드 지지체로 응용될 수 있을 것으로 기대된다. Surface-modified poly(L-lactic acid) (PLLA) films and scaffolds were treated with plasma discharge in oxygen gas and subsequently subjected to in situ grafting of acrylic acid (AA) in order to increase the cell compatibility. The surface of AA-grafted PLLA was converted to hydroxyapatite (HA)-deposited PLLA in stimulated body fluid (SBF). After the samples were immersed in phosphate-buffered saline (PBS), fetal bovine serum (FBS), normal saline, or cell medium, the water contact angles were significantly reduced on the surface of HA-deposited PLLA. Chondrocyte and osteoblast showed a higher attachment and cell proliferation on HA-deposited surfaces and in particular, it was confirmed that chondrocyte was considerably influenced by HA. However, osteoblast showed better cell proliferation on the surfaces immersed in FBS, cell medium or HA-deposited surface. In addition, the cell proliferation in 3D scaffolds was much higher than that on film type, irrespective of chondrocyte and osteoblast. Therefore, such surface-modified PLLAs are expected to be useful as organic-inorganic hybrid scaffolds in the regeneration of cartilage and bone.