Tough and antifouling polyampholyte hydrogels via photopolymerization of equivalent ionic monomers with poly(ethylene glycol) diacrylate

Tough and antifouling polyampholyte hydrogels can be prepared through the photopolymerization of the equivalent [2-(acryloyloxy)ethyl]trimethylammonium chloride([TMA][Cl]) and 2-acrylamido-2-methyl-1-propanesulfonic acid sodium([Na][AMPS]) with poly(ethylene glycol) diacrylate (PEGDA). Fourier-transform infrared spectra evidenced the linkage between PEGDA and TMA/AMPS. With the different ratios of TMA to AMPS, the copolymers presented the different morphological surfaces and also exhibited different swelling ratios. Among all copolymers, the equivalent ionic hydrogel A50S50 ([TMA] = [AMPS]) demonstrated the highest mechanical properties with toughness of 230.98 kJm^-1 and compressive strain of 100%. Hydrogel A50S50 also presented the optimal protein fouling ability for both Bovine-serum-albumin (BSA, anionic protein) and Lysozyme (LYZ, cationic protein). On the other hand, A50S50 also showed the biocompatibility (low cytotoxicity and hemolytic ratio), being certified by MTT assay and hemolysis test. A polyampholyte A50S50 with equivalent ionic monomers possessed both tough and antifouling properties, being highly promising for load-bearing and antifouling biomedical applications.