A collagen GTR membrane was made with a bi-layer structure

one of whose face is loose while the other is tight. The tight face can effectively prevent the cells from growing into the defective tissue zone while the loose face is rough

which is helpful to cells growth and blood clot. In order to improve the physicochemical properties of the membranes

EDC/NHS was used as a cross-linking agent for the membranes. And the effects of cross-linking agent dosage on the physicochemical properties of membranes were investigated. The measurements of DSC

SEM were used to test the structure and properties of the membranes. The properties of water absorption

collagen resistance were also tested. According to the study

0.5 mol/L EDC/NHS

cross-linking 24 h in the pH of 5.5 are the best processing conditions. Increasing further the concentration of EDC can not improve the physicochemical properties of the membranes. The research shows that the physicochemical properties of collagen membranes are improved significantly after being cross-linked. The denaturation temperature

anti-collagen activities are both increased

and the bi-layer structure is kept well.