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Noh, Insup,Choi, Yoon-Jeong,Son, Youngsook,Kim, Chun-Ho,Hong, Seung-Hwa,Hong, Choong-Man,Shin, In-Soo,Park, Sue-Nie,Park, Beom-Young Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of biomedical materials research. Part A Vol.a79 No.4
<P>Strategies of better vascular tissue engineering may require delivery of soluble bioactive signals in cell culture medium to the cells in tissue-regenerating constructs. We measured the diffusivity and permeability of model tissue-engineering bioactive molecules such as water and heparin through the walls of both a hybrid ePTFE graft and a porcine carotid artery, a model vascular tissue. While diffusivities of H<SUP>3</SUP>-water and H<SUP>3</SUP>-heparin were measured as 3.9 × 10<SUP>−</SUP><SUP>6</SUP> and 1.6 × 10<SUP>−</SUP><SUP>6</SUP> cm<SUP>2</SUP>/s in the artery, respectively, under diffusional circulation of cell culture medium through the lumens of the carotid arteries, their corresponding permeabilities were 4.7 × 10<SUP>−</SUP><SUP>5</SUP> and 2.0 × 10<SUP>−</SUP><SUP>5</SUP> cm/s. On the other hand, diffusivities of H<SUP>3</SUP>-water and H<SUP>3</SUP>-heparin were also measured as 5.1 × 10<SUP>−</SUP><SUP>6</SUP> and 4.7 × 10<SUP>−</SUP><SUP>6</SUP> cm<SUP>2</SUP>/s, respectively, in the tissue-engineered hybrid ePTFE grafts; their corresponding permeabilities were 5.1 × 10<SUP>−</SUP><SUP>5</SUP> and 3.7 × 10<SUP>−</SUP><SUP>5</SUP> cm/s. The hybrid graft tissues were engineered by replacing the biodegradable, porous poly(lactide-co-glycolide) layers coated on the ePTFE surfaces with smooth muscle cell-derived tissues for 6 weeks. We analyzed the morphologies of the artery and the engineered hybrid ePTFE tissues with scanning electron microscopy and H&E stains. While the artery had its typical structure properties with layers of intima, media and adventitia, the tissue-engineered ePTFE hybrid graft had two layers of engineered tissues on the inner and outer surfaces of the ePTFE. There were no significant differences among the luminal tissue morphologies of the test samples from the effects of diffusion flow applications, with minor changes on their luminal surfaces. The results of water and heparin diffusion experiments indicated that these bioactive molecules were well transported from the cell culture medium to the tissue-engineering cells, enough to support tissue regeneration. We hope that these transport results may elucidate the transport behaviors of soluble nutrient molecules and biological signals through the vascular constructs under tissue engineering processes. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006</P>
표면개질 된 폴리테트라플르오르에틸렌 필름표면의 세포부착에 관한 연구
노인섭 서울産業大學校 2000 논문집 Vol.51 No.2
Biological interactions were measured on variously treated PTFE films by seeding and culture of human foreskin fibroblasts. Both cell adhesion and spreading were measured by counting the cell numbers and measuring the cell coverage area. The unmodified substrates supported very small amounts of cell adhesion and spreading but the thermo-chemically reduced substrates supported extensive cell adhesion and spreading, presumably via protein adsorption. While the protein adsorption on the unmodified ones were assumed to be hydrophobic interaction, that on the modified ones ionic interaction. While the unmodified PTFE film has only nonionic fluorocarbons, thus inducing interactions of non-ionic portions of the proteins with the hydrophobic film surface, the modified film has various ionic charges, leading to ionic interactions of the ionic portions of the proteins with the hydrophilic surfaces. Surface chemical compositions of both the modified and unmodified PTFE films were verified by electron spectroscopy for chemical analysis. The unique chemical peaks of PTFE films were 292.5eV and the surface modification generated new peaks located around approximately 284.5eV. The new peaks contained unsaturations and other oxygen-containing broad peaks. Dynamic contact angle measurement and low voltage scanning electron microscopy pictures supported the surface modification with its surface tension energy increase showing ionic charges and morphological changes, respectively. These cellular adhesion results may lead to better designs of expanded poly(tetrafluoroethylene) vascular grafts and improve their long-term graft patency.