http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
코팅 용액의 조성 최적화 및 코발트-크롬 금속스텐트의 화학적 표면개질을 통한친수성 천연 고분자 코팅층의 표면 거칠기 개선
금창헌,김대환 한국키틴키토산학회 2018 한국키틴키토산학회지 Vol.23 No.4
Recently, the number of cardiovascular disease-related deaths worldwide has increased. Therefore, the importance of percutaneous cardiovascular intervention and drug-eluting stents (DES) has been highlighted. Despite the great clinical success of DES, the re-endothelialization at the site of stent implantation is retarded owing to the anti-proliferative effect from the coated drug, resulting in late thrombosis or very late restenosis. In order to solve this problem, studies have been actively carried out to excavate new drugs that promote rapid re-endothelialization. In this study, we introduced hydrophilic drug, tauroursodeoxycholate (TUDCA), that improves the proliferation of endothelial progenitor cells and promotes apoptosis of vascular smooth muscle cells. In addition, we utilized shellac, which is a natural resin from lac bug to coat TUDCA on the surface of the metal. When using conventional coating method including biodegradable polymers and organic solvents, phase separation between polymer and drug occurred in the coating layer that caused incomplete incorporation of drug into the polymer layer. However, when using shellac as a coating polymer, no phase separation was observed and drug was fully covered with the polymer matrix. In addition, by adjusting the composition of coating solution and modifying the hydrophilicity of the metal surface using oxygen plasma, the surface roughness decreased due to the increased affinity between coating solution and metal surface. This result provides a method of depositing a hydrophilic drug layer on the stent.
금창헌,한동근,서성호,강성남,박방주,안동준,정윤기 한국고분자학회 2014 Macromolecular Research Vol.22 No.9
Two kinds of magnesium hydroxide (Mg(OH)2) rods (Mg-Rod, 150 and 350 nm in size) and plates (Mg-PL,60 and 300 nm) were prepared, and blended with poly(L-lactide) (PLLA) to obtain PLLA/Mg(OH)2 composites toinvestigate the effect of the shape and size of Mg(OH)2 particles. The structure, morphology, pH change, thermaland mechanical properties, cytotoxicity, and inflammation of Mg(OH)2 control and PLLA/Mg(OH)2 compositeswere evaluated. PLLA/Mg-Rod150 (30%) composite showed a 50% higher tensile strength and a 45% improvedmodulus as compared with PLLA/Mg-PL300 30% composite. Although Mg-Rods displayed similar cell viability(above 80%) as compared to Mg-PLs, the expression levels of TNF-α from Mg-PL60 gradually increased withincreasing concentrations from 1 to 300 μg. This indicates that Mg-PL60 had a potential cytotoxicity due to endocytosis. In addition, the byproduct of PLLA/Mg-Rods composite was more effectively neutralized than that of thePLLA/Mg-PLs composite, but cell viability and the expression levels of TNF-α were similar. Therefore, the use ofour PLLA/Mg-Rod composite system would be a promising strategy to prevent the current fatal problems in biomedicalapplications including biodegradable implants such as stents.