Fabrication Of High Performance PEG-PVDT Hydrogels And Investigation Of Their Nucleoside Responsiveness

Hydrogels have been extensively investigated as biomedical materials because oftheir similar structure and properties with natural soft tissues. However, theirapplication was always limited by its inadequate strength. Although strong hydrogelshad been prepared through many different methods, a hydrogel with excellentcomprehensive mechanical performance was rarely reported. Herein, we fabricatedPEG-PVDT hydrogels with excellent comprehensive mechanical properties via thephotoinitiated free radical copolymerization of2-vinyl-4,6-diamino-1,3,5-triazine(VDT) and chain length modulable polyethylene glycol diacrylates (PEGDA). Theintermolecular hydrogen bonding efects from diaminotriazine were shown to increaseboth the tensile and compressive strengths of the gels up to MPa levels, and longerPEG chains could increase the gel’s elongation toover700%as well as elasticity andfatigue resistance. These high strength and elastic hydrogels with antifatigue abilitymay serve as soft tissue engineering scafolds. In addition, considering that thehydrogen bond between VDT residual groups can be selectively dissociated by someguest molecules, we fabricated a smart hydrogel system with nucleoside as the guestmolecules. The hydrogen bonded hydrogels became increasingly swollen in responseto thymidine due to much stronger competition of DAT-thymidine with DAT-DAThydrogen bonding. The thymidine induced swelling of hydrogels could be exploitedto tune drug release behavior. This proof of concept study offers a new avenue todesign and construct smart vectors capable of delivering target drug by virtue ofnucleosides potentially from endogenously synthesized or indigested diet.