Study On Construction Of A Micro Nano Structure Preparation System For Medical Stents And The Regulation Of Cell Growth By Biomimetic Structure

Laser cutting technology have the advantages of high production efficiency,low cost and high cost performance.At present,most of the stents are made by laser cutting tube.However,there are shortcomings of cutting equipment,such as single processing,poor function and low integration.The micro nano structure is constructed by laser on the surface of the material,and the microstructures of the surface are used to regulate the behavior of the biological cells,which provides a new way to improve the biocompatibility of the materials.In this paper,the micro nano structure preparation system of vascular stent was constructed,the system developed by ourselves has the characteristics of high precision(the precision of platform positioning is ± 2 μm),accurate controllability,high efficiency,high integration and rich function.At the same time,the switchability of nanosecond laser and femtosecond laser provides a variety of options for the research of micro nano structure and functionalization on the stent surface.The influence of laser cutting parameters on the processing technology of 316 L stainless steel tube was studied,the results showed that the optimum power and scanning speed of laser cutting were 15 W,10 mm/s.The surface of the stent was polished by electrochemical polishing(current 1.4 A,polishing temperature 70℃,time 3 min),and the ideal vascular stent was obtained.The surface finishing of the stent was realized,and the surface quality was improved in all directions after laser processing.The stainless steel substrate were processed by nanosecond and femtosecond laser processing technology.Four kinds of micro nano structures were also prepared.The research indicated that the surface hydrophobicity,microhardness and corrosion resistance of micro nano structure are improved compared with blank samples.At the same time,the biological behavior of cells on the surface of micro nano structures were also investigated,the results showed that HUVECs proliferated obviously on these micro nano structure surfaces.The cells showed obvious growth orientation on the micro nano structure surface prepared by the femtosecond laser.However,the cells did not exhibit this phenomenon on the structure of nanosecond laser.The cells appeared spindle and consistent with the direction of micro nano structure groove.The micro nano structure prepared by the femtosecond laser can effectively regulate the growth morphology of the HUVECs.