Instructions: Poly(ε-caprolactone) has excellent biocompatibility, shape memory, biodegradability, etc. It is widely used in various field. PCL is soft and easy to process, It can be used as tissue engineering scaffolds. PCL has low degradation rate and high crystallinity. Its degradation can be divided into two stages in the body. The first stage is that the molecular weight of PCL declines, but no deformation and weightlessness. The second stage is the molecular weight of PCL drops to a certain value, which is followed by the weight loss, gradually uptake and excreting by the body.