Self-Healing Hydrogel Scaffolds through PET-RAFT Polymerization in Cellular Environment

Abstract

Photo electron/energy transfer-reversible addition–fragmentation chain transfer (PET-RAFT) has emerged as a powerful reversible-deactivation radical polymerization technique, enabling oxygen-tolerant polymerizations with exquisite spatiotemporal control through irradiation with visible light. In contrast to traditional free radical photo-polymerization, which often requires the use of DNA-damaging UV irradiation, PET-RAFT offers a more cytocompatible alternative for the preparation of polymeric materials in cell culture environments. Herein, we report the use of PET-RAFT for the fabrication of self-healing hydrogels using commercially available monomers, reaching high monomer conversions and cell encapsulation efficiencies. Our hydrogels showed the expected rheological and mechanical properties for the systems considered, together with excellent cytocompatibility and spatiotemporal control over the polymerization process. Moreover, hydrogels prepared through this method could be cut and healed again by simply adding further monomer and irradiating the system with visible light, even in the presence of mammalian cells. This study demonstrates for the first time the potential of PET-RAFT polymerization as a viable methodology for the synthesis of self-healing hydrogel scaffolds for cell encapsulation.

Oxygen-Tolerant Fabrication of Large-Area Hydrogel Films via Photoinduced Electron/Energy Transfer-Reversible Addition–Fragmentation Chain Transfer Polymerization

“…Recently, photoinduced electron/energy transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization, a controlled/living radical polymerization, has been employed owing to its oxygen tolerance as well as good control over reaction kinetics. − PET-RAFT polymerization requires a combination of a thiocarbonylthio-based RAFT agent, a photoredox catalyst (PC), and a light source with suitable wavelength for the chosen PC, which could range from visible-light − to near-infrared regions . The photoexcited PC reduces and fragments the RAFT agent into anion species and radicals. − The radicals propagate across the media, extending the polymer chain before being reunited with the RAFT agent.…”