Effect of fibre laser process on in-vitro degradation rate of a polycaprolactone stent a novel degradation study method

摘要

In this paper, the authors present the effect of input energy density of Nd:YAG fibre laser upon the degradation rate of the polycaprolactone. The degradation study were carried out with a novel in-vitro method closer to body conditions and were compared with the traditional in-vitro method. This approach was not presented in the available literature. The degradation rate of biodegradable stents is one of the most importance factor upon making these devices, due to it is the property in charge to provide the appropriate period of time to heal the atherosclerosis. The research for a degradable material that shows mechanical properties similar to the current permanent stents in the market and an appropriate degradation rate is still an open challenge. The literature has shown the degradation rate of some biodegradable materials before stent manufacturing's process employing in-vitro degradation methods in static flow conditions which does not match properly with the real body conditions where the blood flow circulate by the vessel. The laser cut samples were analysed by Scanning Electron Microscopy (SEM), Optical Microscopy, and weighing in order to study the effect of laser process, and degradation method over the degradation rates, surface morphology changes, and geometric pattern changes in the stent. Results have shown the influence of the laser process over the degradations rate, accelerating it according the input energy density increases. The dynamic method has increased the weight of samples, fact that will accelerate the degradations rate in a medium period of time that prove the differences that will exist in body conditions.