Study On The Fabrication And Properies Of Biodegradable Blood Vessel Prosthesis Stent

Recently, with the development of biomedical textiles and tissue engineering, the researches about the recovery and regeneration of blood vessel have a good achievement. In our country, the study on blood vessel prosthesis stents has started since 1950's. Although many progresses have been made, the development isn't very prominent due to limited experimental conditions and equipment. At present, there are many different textile structures of blood vessel prosthesis stents, including woven, weft knitted, nonwoven and so on. But all of them have the different disadvantages, such as bad flowing of the woven and uneven surface of the weft knitted structures. Consequently, as a new way, the braided structure has its particular advantages.Absorbable material PDS filament and Chitosan were chosen in this study and different stents were designed and prepared. The work firstly began with braiding and finishing blood vessel prosthesis stents, and then investigated the effects of the different factors on the properties, including compressive properties, superficial properties and biodegradation in vitro and in vivo. The factors include the technical parameter of gears, braided structures, braiding angles, diameters, coating thickness, time and temperature on heat-set, etc.The conclusions obtained show that it is possible to use a braiding machine with 16 gears to produce stent of 4 mm diameter with the regular structure and 70°braiding angles. The heat-setting could be done under the temperature of 70℃in half an hour. The blood vessel prosthesis stent made with these conditions gives the best mechanical properties. On biodegradation experiment in vitro, both the structure and mechanical properties could be maintained during the first 4 weeks and 3 weeks. The thickness and areal average in PDS group were all thinner than those in control groups.The research indicates that the blood vessel prosthesis stent has the excellent mechanical properties and highly effective treatment and feasibility. Consequently, this study will provide credible data for the application on clinic and biomedical textiles.