A Robust, Resilient, and Multi-Functional Soy Protein-Based Hydrogel

Soy protein is one of the most abundant plant protein in nature. Despite numerous studies on soy protein-based materials, the applications of soy protein hydrogel are still extremely limited because of its cumbersome gelation process and poor mechanical properties. Herein, we present a facile method to prepare robust soy protein hydrogels by the introduction of oxidized dextran, a natural polysaccharide derivative, as a macromolecular cross-linking agent. The preparation conditions such as pH value of reaction system and the mass ratio of soy protein to oxidized dextran have been extensively investigated. The resultant soy protein hydrogels exhibit better mechanical properties than the previously reported soy protein-based hydrogels. The best formulated hydrogel shows the compressive modulus of 4.3 kPa and fracture stress of 401 kPa at 87% compression. Also, the hydrogels demonstrate an excellent flexibility to withstand high compression with minimal hysteresis. Owing to the protein and polysaccharides nature of soy protein and dextran, the soy protein hydrogels maintain a good biocompatibility along with excellent mechanical properties. Finally, we show the possibility to design such a soy protein hydrogel as a tolerant multifunctional platform for fluorescence imaging, photothermal therapy, drug carrier, and antibacterial agent. The developed soy protein-based hydrogel is natural, sustainable, robust, and biocompatible and hence has great potential as a multifunctional material for various applications.