Abstract:

BACKGROUND: Current, metal stents mostly used in clinic will permanently stay in the human body, and they can provide potentially risks to human body.
OBJECTIVE: To observe the effects of modification on poly-L-lactic acid (PLLA) and the feasibility of preparation of biodegradable stents with modified materials. 
METHODS: PLLA, polylactic acid/polycaprolactone (PLCL-J) and PLLA/polycaprolactone (PLCL-H) films were prepared by solution method with the modification ratio of PLLA/polycaprolactone of 95/05. Comparative observation of changes in mechanical property, intrinsic viscosity and mass loss, and changes in surface morphology of PLLA, PLCL-H and PLCL-J was performed with film degradation test. 
RESULTS AND CONCLUSION: Mechanical property test showed that the brittleness of PLLA materials was significantly increased after 3 months. The materials were easy to break, and this was a major defect in preparing stents; the mechanical properties of PLCL-J lost too fast, its yield completely disappeared at 3 weeks, its tensile strength began to decline sharply at 4 weeks, and its mechanical property completely disappeared at 10 weeks; PLCL-J material not only had high initial breaking elongation, but also kept a high flexibility during the degradation process. Intrinsic viscosity detection and surface morphology observation showed that PLCL-J material was not suitable for stent preparation based on its fast degradation rate, while the degradation rates of PLLA and PLCL-H materials were uniform, and the degradation rate of PLCL-H material was increased compared with PLLA material. The blending material of PLLA and polycaprolactone with modification ratio of 95/05 can not only ensure the mechanical strength of stents, but also increase breaking elongation of stents, and these make it can be used as a new type of material for preparation of biodegradable stents through an increase in plasticization and degradation rate of the material.