Among the designs left by leonardo da vinci almost 500 years ago ? with notes written backward to be read with a mirror ? were the parachute ， life jacket ， water pump ， swim fins ， well digger ， paddle - wheel boat ， horseless carriage ， sprocketchain ， steam gun ， water turbine ， lens - grinding0 machine ， shrapnel ， machine gun ， airplane ， helicopter ， submarine ， and mass production 近500年前列奥纳多?达?芬奇留下的许多设计稿? ?即须通过镜子才能读懂的反着写的笔记，其中有降落伞、救生衣、水泵、游泳脚蹼、钻井机、明轮机、无马马车、扣齿链、蒸汽枪、水轮机、磨镜片机、子母弹、机关枪、飞机、直升飞机、潜水艇和成批生产的设计。
The basis of these technologies is cellular matrix . it must have biocompatibility , surface compatibility , structure compatibility . biodegradation , and it also can be sterilized . because people can control the synthetic matrix appearance , dimension , intensity degradation rate and three dimensional , they used to use it . but it also brings biocompatibility and infection 过去所用的支架一般为合成支架，它的优点是人们可以随心所欲地控制支架的形态、尺寸、强度、降解时间、降解速度及三维结构，并可成批生产，但也带来了诸如：生物不相容性，感染问题等，而且合成支架在表面相容性和结构相容性上有诸多不尽如人意之处。
