以戊二酸锌为催化剂合成可降解聚碳酸亚丙亚乙酯(PPEC,MW=229.338kDa)并首次将其作为载药涂层材料进行研究。核磁共振氢谱(1 H NMR)显示分子链中环氧乙烷和环氧丙烷的贡献与原料中两者配比相同,碳酸酯段含量为76.7%。差示扫描量热仪(DSC)测得玻璃化转变温度(Tg)为16.8℃。拉伸实验得到断裂伸长率为550%。衰减全反射-傅立叶变换红外光谱(ATR-FT-IR)显示药物涂层中PPEC和雷帕霉素之间没有发生明显的化学反应。球囊扩张实验后用扫描电子显微镜(SEM)观察到药物涂层支架表面完整光滑,没有剥落翘起的现象。药物洗脱支架在模拟体液(PBS,pH值=7.4)中药物释放时间超过60d,速率由快变慢。实验表明PPEC作为支架涂层材料具有广阔的应用前景。
Background To overcome the drawbacks of permanent years. The bioabsorbable polymer vascular scaffold （BVS） stents, biodegradable stents have been studied in recent was the first bioabsorbable stent to undergo clinical trials, demonstrating safety and feasibility in the ABSORB studies. Iron can potentially serve as the biomatedal for biodegradable stents. This study aimed to assess the short4erm safety and efficacy of a biodegradable iron stent in mini-swine coronary arteries. Methods Eight iron stents and eight cobalt chromium alloy （VISION） control stents were randomly implanted into the LAD and RCA of eight healthy mini-swine, respectively. Two stents of the same metal base were implanted into one animal. At 28 days the animals were sacrificed after coronary angiography, and histopathological examinations were performed. Results Histomorphometric measurements showed that mean neointimal thickness （（0.46±0.17） mm vs. （0.45±0.18） mm, P=0.878）, neointimal area （（2.55±0.91） mm2 vs. （3.04±1.15） mm2, P=0.360） and percentage of area stenosis （（44.50±11.40）% vs. （46.00±17.95）%, P=0.845） were not significantly different between the iron stents and VISION stents. There was no inflammation, thrombosis or necrosis in either group. The scanning electron microscopy （SEM） intimal injury scores （0.75±1.04 vs. 0.88±0.99, P=0.809） and number of proliferating cell nuclear antigen （PCNA） positive staining cells were not significantly different between the two groups. The percentage of neointimal coverage by SEM examination was numerically higher in iron stents than in VISION stents （（84.38±14.50）% vs. （65.00±22.04）%, P=0.057）, but the difference was not statistically significant. Iron staining in the tissue surrounding the iron stents at 28 days was positive and the vascular wall adjacent to the iron stent had a brownish tinge, consistent with iron degradation. No abnormal histopathological changes were detected in coronary arteries or major organs. Conc
Background Iron is a biocorrodible metal that might be used in bioabsorbable stents.This study investigated the effects at the cellular and protein levels of soluble divalent iron （ferrous gluconate） and soluble trivalent iron （ferric chloride） on the proliferation of human aortic smooth muscle cell （HASMC） in vitro.Methods The water-soluble tetrazolium （WST-1） test was used to evaluate the effect of iron on proliferation of HASMC and Western blotting was used to measure the levels of signaling proteins involved in proliferative and apoptosis pathways.Results HASMC proliferation was inhibited in a concentration dependent manner after treatment with soluble divalent and trivalent iron at concentrations of 100-500 μmol/L.Western blotting analysis showed that the proliferating cell nuclear antigen （PCNA） expression following treatment with soluble divalent iron and trivalent iron at 100,300 and 500 μmol/L was reduced compared to the control.The PCNA expression decreased with increasing iron concentration and to a greater extent with the trivalent iron than with the divalent iron treatment group.The p53 expression was markedly increased in a concentration dependent manner in both iron treatment groups.Conclusion The soluble divalent iron and,to a greater degree trivalent iron,inhibited HASMC proliferation in a dosedependent manner,which may be attributed to reduction of PCNA expression and increase of p53 expression.
In this study, the surface passive films, dissolution behavior and biocompatibility of Ti-Ag alloys （with 5%, 10% and 20% Ag） were evaluated by X-ray diffraction （XRD） tests, electrochemical corrosion tests, X-ray photoelectron spectroscopy （XPS） tests, dissolution tests and in-vitro cytotoxicity tests. The surface films on the Ti-20Ag alloy are rich in Ti and much deficient in Ag with respect to alloy composition, as identified by XPS. Compared to CP Ti, Ti-SAg and Ti-20Ag alloys show larger impedances and lower capacitances, which can be associated with an increase of the passive layer thickness. Moreover, all Ti-Ag alloys exhibit negligible or low metal release in the test solutions. The in-vitro cytotoxicity results show Ti-Ag alloys seem to be as cytocompatible as CP Ti. From the viewpoint of surface passive film and cytotoxicity, Ti-SAg and Ti-20Ag are considered to be more suitable for dental applications.
