A comprehensive study and comparison of four types of zwitterionic hydrogels

Zwitterionic materials have been attracting significant attentions due to their excellent non-fouling and biocompatible properties and thus have been widely used in many biomedical applications. However, differences among different types of zwitterionic materials have rarely been investigated and compared. In this work, four types of zwitterionic monomers were systematically studied and compared by testing the properties of the hydrogels. Their hydration, diffusion coefficient of water and mechanical properties were evaluated and analyzed. It was found that poly(carboxybetaine methacrylate) (PCBMA) hydrogel possessed the strongest compressive modulus, while poly(carboxybetaine acrylamide) (PCBAA) hydrogel showed the highest diffusion coefficient of water and highest hydration of water. Compared with other hydrogels, the mesh size of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) hydrogel was the largest. Furthermore, poly(sulfobetaine methacrylate) (PSBMA) hydrogel with disulfide crosslinker degraded faster than the others. Findings in this work provided insights and guidance for the selection of different zwitterionic polymers to suit different applications.