High strength biocompatible PEG single-network hydrogels

Abstract

In this work, PEG-based single-chain hydrogels with extremely high strength were successfully prepared via precise design and control over the molecular topology of the polymeric network. Initially, well-defined PEG macromolecules with uniformly dispersed pendant alkynyl groups (PEG_n(CCH))_m on their main chains were synthesized via amine-epoxy chain extension reaction of α,ω-diepoxy PEG and propargylamine. The subsequent copper(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition (CuAAC) of (PEG_n(CCH))_m and α,ω-diazido PEG_n (PEG_n(N₃)₂) gave rise to tough PEG-based hydrogels (Gel-PEG_n(N₃)₂-(PEG_n(CCH))_m). The lattice size of the Gel-PEG_n(N₃)₂-(PEG_n(CCH))_m networks can be tailored by varying chain lengths of PEG repeating segments in (PEG_n(CCH))_m and PEG_n(N₃)₂. Different from traditional PEG hydrogels prepared by CuAAC, such as hydrogels from tetrakis(2-propynyloxymethyl)methane and PEG_n(N₃)₂, the current novel hydrogels possess not only a high mechanical strength up to 62.5 MPa, but are also biodegradable favored by the presence of triethylamine groups in the (PEG_n(CCH))_m macromolecules. Furthermore, excellent biocompatibility of the Gel-PEG_n(N₃)₂-(PEG_n(CCH))_m was demonstrated according to the in vitro cytotoxicity assay. Hence, it can be ascertained that Gel-PEG_n(N₃)₂-(PEG_n(CCH))_m has promising potential for artificial medical devices or scaffolding materials for regenerative medicine.