Potential Environmental Application of Self-Assembled Protein Hydrogel Based on Elastin-like Protein Sequences

U. Loi Lao1, Philip Hehn1, Gabriela Jenikova1, Ashok Mulchandani2, and Wildred Chen1. (1) Chemical and Environmental Engineering, University of California, 900 University Avenue, Riverside, CA 92521, (2) University of California, Riverside, Bourns Hall B317, Riverside, CA 92521

Recombinant DNA methods have enabled the creation of protein-based block copolymers with programmable sequences, desired properties and predictable three-dimensional structures. These advantages over conventional polymer counterparts facilitate the utility of this new class of biomaterials in a wide range of applications.

In this project, we exploit the potential environmental application of protein-based block copolymers based on elastin-like protein (ELP) sequences. Triblock copolymers containing charged and hydrophobic segments were synthesized. Chain lengths of each segment were manipulated in order to maintain a gelation point below room-temeperature. Polyhistidine sequences were successfully incoporated into the hydrophilic segment without disruption of the self-assembled hydrogel formation. The microscopic structure was investigated by Laser Confocal Microscopy to evaluate the robustness of gel formation under different conditions.

The metal binding capability and capacity of resulting hydrogel was studied to demonstrate the functionality of polyhistidine and potential application of this genetically engineered hydrogel as a permeable barrier material for underground water treatment. Reversibility of metal binding was demonstrated, indicating the cost-effectiveness of this hydrogel barrier system.