Collagen is the most abundant and widely distributed functional protein in mammals, accounting for 25 % to 30 % of total protein. Collagen is a natural protein of the muscle, which has greater affinity for protein molecules on the skin surface, weaker antigenicity, good biocompatibility and biodegradation safety. Therefore collagen has gained wide application in food, medicine, tissue engineering, cosmetics and other fields. https://www.3dmicroflu.com/pro....tein-based-bioinks.h