• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.108-108
• /
• 2017

다양한 생체 재료들을 이용한 마이크로 및 나노 크기의 표면 구조 모사는 조직공학에서 세포의 성장 및 분화에 영향을 미치는 것으로 알려져 있다. 특히, 마이크로-나노 구조가 공존하는 계층적 표면 구조는 골 아세포의 증식과 분화에 탁월하여 뼈 조직 재생에 응용되어 왔다. 기존에는 화학적 처리 기법을 이용하여 마이크로 표면 구조가 제작 되었으나 미세 거칠기 및 계층적 표면 구조의 제어가 어려웠다. 현재 이러한 문제점들을 극복하기 위해 플라즈마를 이용한 애칭 기법이 주로 이용되고 있으나 높은 온도 공정 환경에 의한 재료 선택의 한계점 및 오랜 공정 시간에 의한 플라즈마 처리 효율이 감소되어 원하는 표면구조 및 거칠기를 얻을 수 없다는 단점이 있다. 본 연구에서는 이러한 문제점들을 극복하기 위해 마이크로/나노 주조 기법 이용하여 생체적합성 합성고분자 poly(${\varepsilon}$-caprolactone) (PCL) 위에 연꽃잎 구조를 모사한 후 플라즈마 애칭 기법을 이용하여 마이크로-($3.01-3.07{\mu}m$)와 나노크기 ($97{\pm}16nm$)를 동시에 갖는 계층적 구조를 제작하였다. 제작된 구조의 효능을 관찰하기 위해 조골세포를 배양한 결과 평평한 PCL 구조보다 제작된 계층적 구조가 높은 세포성장률 (>2.9배)및 세포 분화도(>2.1배)를 보였다. 이러한 결과는 새로운 표면 공학적 모델로서 손상된 뼈 및 치아조직 재생을 위한 적합한 거칠기 및 표면적인 환경을 제공해 빠른 재생 능력과 더불어 치료기간의 단축을 가져 올 수 있을 것으로 사료된다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.2
• /
• pp.169-176
• /
• 2015

The mechanical properties of living tissues have been major subjects of interest in biomechanics. In particular, the characteristics of very soft materials such as the brain have not been fully understood because experiments are often severely limited by ethical guidelines. There are increasing demands for studies on remote medical operations using robots. We conducted compression tests on brain-like specimens made of gelatin to find substitutes with the mechanical properties of brain tissues. Using a finite element analysis, we compared our experimental data with existing data on the brain in order to establish material models for brain tissues. We found that our substitute models for brain tissues effectively simulated their mechanical behaviors.

• Reproductive and Developmental Biology
• /
• v.31 no.1
• /
• pp.1-6
• /
• 2007

The nonobese diabetic / severe combined immune deficiency (NOD/SCID) has been used for determination of proliferation and differentiation of hematopoietic stem cells as xenotransplantation animal model. In this study, we transplanted porcine hematopoietic cells from bone marrow into NOD/SCID mice via intravenous injection to confirm the activity of differentiation and proliferation for porcine hematopoietic cells in vivo. Interestingly, we observed the result of high efficiency with pig T lymphocytes in hematopoietic organs, liver, spleen lymph node, and bone marrow in NOD/SCID mice. The porcine $CD3^{+}$ T cells were detected with $5.4{\pm}1.9%$ in bone marrow, $15.4{\pm}7.3%$ in spleen, $21.3{\pm}1.4%$ in liver, and $33.5{\pm}32.8%$ in lymph node of NOD/SCID mice at 6 weeks after trans-plantation Furthermore, immunohistochemical analysis showed the high engraftment of porcine T lymphocytes in spleen of NOD/SCID mice. Our data suggest that NOD/SCID mice are excellent animal model to determinate the generation md function of pig T lymphocytes.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.10
• /
• pp.953-959
• /
• 2013

In this study, a multibody dynamic model of the cervical spine was developed for a virtual in-vitro cadaveric experiment. The dynamic cervical spine model was reconstructed based on Korean CT images and the material properties of joints and soft tissue obtained from in-vitro experimental literature. The model was validated by comparing the inter-segmental rotation, multi-segmental rotations, load-displacement behavior, ligament force, and facet contact force with the published in-vitro experimental data. The results from the model were similar to published experimental data. The developed dynamic model of the cervical spine can be useful for injury analysis to predict the loads and deformations of the individual soft-tissue elements as well as for virtual in-vitro cadaveric experiments.

• Proceedings of the Optical Society of Korea Conference
• /
• 2006.07a
• /
• pp.535-536
• /
• 2006

• Korean Chemical Engineering Research
• /
• v.54 no.3
• /
• pp.285-292
• /
• 2016

Three-dimensional (3D) printing is driving major innovation in various areas including engineering, manufacturing, art, education and biosciences such as biochemical engineering, tissue engineering and regenerative medicine. Recent advances have enabled 3D printing of biocompatible materials, cells and supporting components into complex 3D functional tissues. Compared with non-biological printing, 3D bioprinting involves additional complexities which require the integration of technologies from the fields of biochemical engineering, biomaterial sciences, cell biology, physics, pharmaceutics and medical science.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.05a
• /
• pp.681-684
• /
• 2006

본 논문은 능동형상모델(Active Shape Model: ASM)을 사용하여 손바닥의 형상을 추출하고 경계형상을 추적하기 위한 방법을 제안한다. 먼저, 경계추적을 위한 초기위치를 입력하기 위해 컬러영상에서 피부색영역의 위치 정보를 통해 중심점을 찾고 그 값을 통해 ASM을 이용하여 손바닥의 영역을 찾는다. ASM은 다양한 경계형상의 학습을 통해 평균값과 형상의 지배적 변형을 나타내는 형상벡터를 추출하기 위한 방법론이며 생체조직과 같은 형상이 일정하지 않고 평균형상을 기준으로 변화하는 형상의 외형을 추출, 추적하기에 적합한 기술이다. 본 논문에서는 피부색 특징을 이용하여 초기 손바닥의 위치를 찾고 이러한 위치정보를 이용하여 손 경계형상의 변화를 추적하는 방법을 실험을 통해 검증하였다

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2002.11a
• /
• pp.46-58
• /
• 2002

포도당 대사에서 중심적인 역할을 담당하고 있는 호르몬인 인슐린의 작용기전은 이전에 알려진 것보다 매우 다양하고 복잡한 세포내 신호전달 체계에 의해서 수행된다. 지난 10여년간 이러한 세포 신호전달 흐름내 중간물질인 여러 가지 단백질의 역할에 대해서 많은 연구가 진행되어 적지 않은 성과를 거두고 있다. 근래에는 해당 유전자에 대해 분자생물학적인 조작을 가하여 실험동물 체내에서 이러한 중간 단백질이 발현되지 못하도록 한 후, 각 조직에서의 인슐린 신호전달 체계를 더욱 심도 있게 연구하고 있다. 여러 연구방법 가운데서, 특히 조직 특이적으로 특정 유전자를 제거하여 태어난 개체를 이용하고, 또한 이들을 서로 교배시켜 나타나는 현상을 연구하여 비정상적인 포도당대사를 이해하는데 많은 도움을 받고 있다. 동물종에 따른 대사상의 차이점 등으로 인해 적지 않은 한계를 갖고 있지만, 동물 질환모델은 포도당 대사와 같은 생체 내에서 중요한 작용을 깊게 이해하고 더 나아가서는 비정상적인 대사를 밝히는데 핵심적인 역할을 수행하고 있다. 기초분야의 성과를 활용하는 응용학문인 축산분야에서도 이러한 접근방법과 연구 결과는 시사하는 바가 있을 것이다.

• Journal of Life Science
• /
• v.34 no.5
• /
• pp.339-355
• /
• 2024

The pulmonary system is a highly complex system that can only be understood by integrating its functional and structural aspects. Hence, in vivo animal models are generally used for pathological studies of pulmonary diseases and the evaluation of inhalation toxicity. However, to reduce the number of animals used in experimentation and with the consideration of animal welfare, alternative methods have been extensively developed. Notably, the Organization for Economic Co-operation and Development (OECD) and the United States Environmental Protection Agency (USEPA) have agreed to prohibit animal testing after 2030. Therefore, the latest advances in biotechnology are revolutionizing the approach to developing in vitro inhalation models. For example, lung organ-on-a-chip (OoC) and organoid models have been intensively studied alongside advancements in three-dimensional (3D) bioprinting and microfluidic systems. These modeling systems can more precisely imitate the complex biological environment compared to traditional in vivo animal experiments. This review paper addresses multiple aspects of the recent in vitro modeling systems of lung OoC and organoids. It includes discussions on the use of endothelial cells, epithelial cells, and fibroblasts composed of lung alveoli generated from pluripotent stem cells or cancer cells. Moreover, it covers lung air-liquid interface (ALI) systems, transwell membrane materials, and in silico models using artificial intelligence (AI) for the establishment and evaluation of in vitro pulmonary systems.

• Journal of Veterinary Clinics
• /
• v.28 no.5
• /
• pp.486-496
• /
• 2011

A special mesenchymal tissue layer called perichondrium has a chondrogenic capacity and is a candidate tissue for engineering of cartilage. To overcome limited potential for chondrocyte proliferation and re-absorption, we studied a method of cartilage tissue engineering comprising chondrocyte-hydrogel pluronic complex (CPC) and cultured perichondrial cell sheet (cPCs) which entirely cover CPC. For effective cartilage regeneration, cell-sheet engineering technique of high-density culture was used for fabrication of cPCs. Hydrogel pluronic as a biomimetic cell carrier used for stable and maintains the chondrocytes. The human cPCs was cultured as a single layer and entirely covered CPC. The tissue engineered constructs were implanted into the dorsal subcutaneous tissue pocket on nude mice (n = 6). CPC without cPCs were used as a controls (N = 6). Engineered cartilage specimens were harvested at 12 weeks after implantation and evaluated with gross morphology and histological examination. Biological analysis was also performed for glycosaminoglycan (GAG) and type II collagen. Indeed, we performed additional in vivo studies of cartilage regeneration using canine large fullthickness chondrial defect model. The dogs were allocated to the experimental groups as treated chondrocyte sheets with perichondrial cell sheet group (n = 4), and chondrocyte sheets only group (n = 4). The histological and biochemical studies performed 12 weeks later as same manners as nude mouse but additional immunofluorescence study. Grossly, the size of cartilage specimen of cPCs covered group was larger than that of the control. On histological examination, the specimen of cPCs covered group showed typical characteristics of cartilage tissue. The contents of GAG and type II collagen were higher in cPCs covered group than that of the control. These studies demonstrated the potential of such CPC/cPCs constructs to support chondrogenesis in vivo. In conclusion, the method of cartilage tissue engineering using cPCs supposed to be an effective method with higher cartilage tissue gain. We suggest a new method of cartilage tissue engineering using cultured perichondrial cell sheet as a promising strategy for cartilage tissue reconstruction.