Conjugation of Methacrylamide Groups to a Model Protein via a Reducible Linker for Immobilization and Subsequent Triggered Release from Hydrogels

Abstract

An efficient strategy is reported to introduce methacrylamide groups on the lysine residues of a model protein (lysozyme) for immobilization and triggered release from a hydrogel network. A novel spacer unit was designed, containing a disulfide bond, such that the release of the protein can be triggered by reduction. The modified proteins were characterized by MALDI-TOF MS, titration of free NH(2) residues and spectral analysis. The modification reaction is well controlled, and the number of introduced functions can be tailored by changing the reaction conditions. Gel electrophoresis experiments showed that the methacrylamide modified protein can be immobilized in a polyacrylamide hydrogel and subsequently released by reduction of the spacer by which the protein was grafted to the polymeric network.

Microstructured dextran hydrogels for burst-free sustained release of PEGylated protein drugs

“…Although burst release can be reduced to some extent, raising the degree of crosslinking often causes incomplete release via the permanent entrapment of proteins in regions of the hydrogel where the mesh size is smaller than the size of the protein drug [21]. Alternatively, burst release can be suppressed by tethering protein drugs to the hydrogels via a cleavable linker [22,23], or by incorporating protein-loaded poly(lactic-co-glycolic acid) micro/nanospheres in a bulk hydrogel matrix [24,25].…”

Reduction‐Sensitive Dextran Nanogels Aimed for Intracellular Delivery of Antigens

“…This method was recently used by Verheyen et al with bulk hydrogels and by Matsumoto et al with nanogels. [ 13 ] The disulfi de bonds between proteins and nanogels are stable in the extracellular environment but are degraded in the cytosol of cells, because of relatively high intracellular levels of glutathione as compared with the extracellular space, [ 14 ] so that triggered release of the loaded antigen can be achieved after their internalization by DCs ( Scheme 1 ). This study focuses on developing antigen-nanogel conjugates, using ovalbumin (OVA) as the model protein antigen, which show triggered release of their payload in a reductive environment.…”

Protein–Hydrogel Interactions in Tissue Engineering: Mechanisms and Applications

“…For example, genipin, a naturally occurring crosslinker, has toxicity levels 10,000-fold lower than glutaraldehyde. 80 Further, the acrylate functionality, which is responsible for photopolymerization of PEG-diacrylate gels, is utilized for several protein-hydrogel crosslinking reactions, including cleavable protein hydrogel crosslinkers (2-(2pyridin-2-yldisulfanyl)ethyl 2-(methacrylamido)acetate in Table 1) 81,82 and degradable hydrogels, where redox poly-merization strategies allows for in-situ cell encapsulation. 83 HA has been similarly modified with methacrylate to obtain gels that encompass the range of physiologically relevant mechanical properties, while maintaining HA cell receptors.…”