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Objective: To prepare a mitomycin C (MMC)-eluting stent for biliary tract, and to observe the drug delivery from the stent. Methods: The mixed powder of MMC and polylactic glycolic acid (PLGA) was dissolved with their common solvent tetrahydrofuran (THF), with a drug concentration of 1%. The 6Fr biliary stent was soaked in the above solution for 10 min, and then was subjected to vacuum drying and was stored at room temperature. Then MMC-eluting stent was weighed and the MMC load was calculated. The MMC-eluting stents were soaked in 8 ml phosphate buffered saline (PBS, pH 7. 4) and placed in a shaker at a constant temperature of 37°C for 24 h soaking; then fresh PBS was changed every day for 30 days. The leaching solutions of the 1-30 days were subjected to chromatographic analysis to determine the concentrations of MMC. Results: MMC load on each stent was (216. 20 ± 2. 04) g, with the load per unit area being (0. 732 ± 0. 007) g/mm2. MMC could be released from the stent surface in a sustainable manner. The elution concentration of MMC was (1. 81 ± 0. 06) g/ml on first day and (1. 24 ± 0. 04) g/ml on the second day; then it fluctuated within 0. 61-0. 84 g/ml. The concentration of MMC began to decrease from the 21st day, and it was (0. 51 + 0. 01) g/ml on the 30th day. Conclusion: MMC-eluting biliary stents can be successfully prepared using polylactic acid as a drug carrier. In vitro study shows that the drug-eluting stents can sustainably and stably release MMC for over 30 days.
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Objective To explore the effects of surface modification of PLGA-[ASP-PEG] scaffold with typeⅠcollagen on the adhesion,proliferation and osteogenic differentiation of rabbit bone marrow stromal cells (BMSCs).Methods After PLGA-[ASP-PEG] materials were modified with typeⅠcollagen chemically,the collagen was coated onto the materials physically.The BMSCs obtained from rabbits were cultured on the modified PLGA-[ ASP-PEG] and on the unmodified PLGA-[ ASP-PEG] as control.The adhesion and proliferation behavior of the cells was analyzed and the expressions of osteogenie marker alkaline phosphatase,osteocalcin,osteopontin,typeⅠcollagen and core binding factor al were also detected.Results X-ray photoelectron spectrometry(XPS) confirmed that TypeⅠcollagen was grafted onto the surface of PLGA-[ASP-PEG] successfully and the collagen content on the materials modified chemically and physically was significantly increased.The abilities of adhesion and proliferation and the expressions of osteogenie makers of the BMSCs were significantly greater than those in the control group(P＜0.05).Conclusion Since Type collagen I can improve the biocompatibility of PLGA- [ASP-PEG] scaffold materials,it can be used as a new way to optimize scaffolds in tissue engineering.