This invention of new biomaterials of alternating block polyurethanes (AltPU) based on biodegradable polyester blocks and hydrophilic blocks such as polyethers are created through a selectively coupling reaction between aliphatic polyester diols and diisocyanate-terminated hydrophilic polyethers or between aliphatic polyester diols and diisocyanate-terminated aliphatic polyester blocks under catalysis of organic tin compounds. AltPU possess well-controlled and defined chemical structures as well as regular polymer chain architecture and surface microstructures. The alternating block polyurethane designs endow materials with more special and intriguing properties, such as better biocompatibility, higher hydrophilicity, and favorable mechanical and material processing properties. Medical devices made of AltPU biomaterials show outstanding performance in peripheral nerve repair. In peripheral nerve repair (NGC), NGCs made of AltPU exhibit even better repair results than autograft, without adding any additional growth factors or proteins on SD rat model. The NGCs can also contain bioactive substances. The AltPU biomaterials can be widely used for many medical and non-medical applications including but not limited to tissue regeneration of soft and hard tissues, medical tubings and catheters, device coatings, and other applications.