Degradable Polyurethane with a Zwitterionic Precursor for Healthy Healing

Implanted synthetic elastomers fail to promote healthy healing due to foreign body reactions and disruptions caused by degraded byproducts. In this work, a degradable polyurethane incorporating carboxybetaine ester (CBE) analogues and polylactide (PLA) was synthesized to offer excellent resistance to nonspecific adsorption and to maintain a balanced physiological pH after hydrolysis. Histological analysis revealed no collagen deposition and accelerated fur regrowth after 6 weeks of subcutaneous implantation of the optimized formulation (PLA/CBE = 1:1), compared to significant fibrous encapsulation observed in PLA controls. This optimal healing outcome results from the regeneration of surface zwitterions to sustain protein resistance and the reduction of acidification in the implanted microenvironment by weakly basic CBE analogues, which effectively address immunogenicity challenges and inflammation caused by tissue acidification during PLA degradation. This research demonstrates the potential for healthy healing after implanting degradable synthetic elastomers, addressing a critical issue in the field of synthetically degradable polymers.