As a three-dimensional construct used in tissue engineering,scaffold is one of the major elements together with cells and signaling molecules that has been developed for cell adhesion,proliferation and differentiation during the past several decades [1].Many natural and synthetic polymers such as collagen,chitosan and poly(vinyl alcohol)et al.have been investigated as scaffolds in clinical applications because of their biocompatible and biodegradable features and suitable surface chemical composition and physical structure for cell and tissue growth [2].