Protein-Based Hydrogels and Their Biomedical Applications.

Hydrogels made from proteins are attractive materials for diverse medical applications, as they are biocompatible, biodegradable, and amenable to chemical and biological modifications. Recent advances in protein engineering, synthetic biology, and material science have enabled the fine-tuning of protein sequences, hydrogel structures, and hydrogel mechanical properties, allowing for a broad range of biomedical applications using protein hydrogels. This article reviews recent progresses on protein hydrogels with special focus on those made of microbially produced proteins.

Bi-terminal fusion of intrinsically-disordered mussel foot protein fragments boosts mechanical strength for protein fibers.

Microbially-synthesized protein-based materials are attractive replacements for petroleum-derived synthetic polymers. However, the high molecular weight, high repetitiveness, and highly-biased amino acid composition of high-performance protein-based materials have restricted their production and widespread use. Here we present a general strategy for enhancing both strength and toughness of low-molecular-weight protein-based materials by fusing intrinsically-disordered mussel foot protein fragments to their termini, thereby promoting end-to-end protein-protein interactions.

Microbial Synthesis of High-Molecular-Weight, Highly Repetitive Protein Polymers.

High molecular weight (MW), highly repetitive protein polymers are attractive candidates to replace petroleum-derived materials as these protein-based materials (PBMs) are renewable, biodegradable, and have outstanding mechanical properties. However, their high MW and highly repetitive sequence features make them difficult to synthesize in fast-growing microbial cells in sufficient amounts for real applications. To overcome this challenge, various methods were developed to synthesize repetitive PBMs.

Injectable, photoresponsive hydrogels for delivering neuroprotective proteins enabled by metal-directed protein assembly.

Axon regeneration constitutes a fundamental challenge for regenerative neurobiology, which necessitates the use of tailor-made biomaterials for controllable delivery of cells and biomolecules. An increasingly popular approach for creating these materials is to directly assemble engineered proteins into high-order structures, a process that often relies on sophisticated protein chemistry. Here, we present a simple approach for creating injectable, photoresponsive hydrogels via metal-directed assembly of His6-tagged proteins.