All biomass bovine serum albumin/alginate hydrogels: robust mechanical strength and excellent shape memory performance regardless of protein denaturation

Shape memory materials made from biomacromolecules are eco-friendly but often display low mechanical strength and inferior shape memory performance. This study innovatively created a shape memory hydrogel (SMH) using bovine serum albumin (BSA) and alginate. Through a protein-unfolding-chemical coupling strategy, the prepared hydrogel achieved outstanding mechanical strength that made it mechanically robust enough to be handled in practical applications. The hydrogel showed excellent shape memory performance, with a shape fixing ratio of 93.8% and a shape recovery ratio of 100%. The complexation between alginate and Fe3+ made the shape memory performance insensitive to the secondary structure of BSA, remaining consistent even after extreme denaturation treatment. Composed entirely of biomacromolecules, the SMH was fully biodegradable and sustainable. In summary, the BSA/alginate-based SMH, with high mechanical strength, excellent shape memory performance, and biodegradability, holds great potential as sustainable and versatile shape memory hydrogels.