3D Printing Degradable Vascular Stent System Development And Experimental Research

Vascular stents work as the main medical device for the treatment of stenosis occlusion blood vessels and the effect of treatment depends largely on the itself. In recent years, domestic and foreign research on vascular stent mainly involves materials, structure, molding process and so on. Among which, the stent forming process has been an important factor restricting the development of stents. This paper aims to study 3D printing system and the molding process of biodegradable vascular stent, which provides a new idea for the preparation of vascular stent. The details of this article are as follows:(1)Using the biodegradable vascular stent as the object of this paper, we utilize finite element method to examine the expansion procedure, stent compression and bending deformation process of vascular bolster single annular support. Firstly, we introduce the general process of three-dimensional modeling of the stent and compare several structural annular supports to determine the structure type of the stent unit.Secondly, the effects of different structures and different widths of the stent of polylactic acid on the stent expansion were analyzed. The structures can be divided into "sine","60 degrees sine" and "U" type and the width ranges from 4mm to 8mm with the span of 2mm. The results show that the sine type brackets are more suitable for medical stent implantation in terms of mechanical properties.(2)In this paper, a three-dimensional deposition of vascular stent based on composite motion is proposed. Based on the principle of melt deposition of biodegradable vascular stent, we design the mechanical structure of each part of the forming system, including nozzle structure, forming rotary shaft and triaxial transmission mode and design the motion control system of the forming system,including the main control module, the motion control module, the nozzle control module, etc.(3)The effects of system parameters on the microstructure and mechanical properties of vascular stents are also be studied. The error of the roll-type melt-deposition process including the error of the molding equipment itself, the error caused by the spinning width and the error caused by the shrinkage of the material is analyzed, which provides providing experimental basis to improve the properties of the stent.(4)Study of brachial artery stent implantation in experimental animals with three-dimensional vascular stents indicates that the design of the vascular stent can expand the stenosis of the blood vessels, so that the blood vessels to complete the normal blood supply function and has a good biocompatibility and degradation, which is of great theoretical and experimental significance for the clinical transformation of biodegradable vascular stents.