Shear-Induced Fibrillation and Adhesion Quantification of Protein Hydrogels: Case of BSA and Lysozyme

Quantifying adhesion in protein-based systems remains challenging, particularly for bioinspired materials, such as barnacle cement, where adhesion emerges from the hierarchical assembly of proteins into amyloid like fibrillar networks and sample availability is inherently limited. Here, we developed an in situ shear-controlled approach to trigger fibrillation-driven gelation and measure adhesion, by controlling temperature, humidity and shear while using relative small sample volumes (∼180 μL). The approach was validated using model proteins, Bovine Serum Albumin and Lysozyme at different pH and ionic strengths, which exhibit distinct fibrillation pathways. Gel formation was monitored under oscillatory shear measurements, followed by in situ adhesion measurements through normal force-displacement analysis. Complementary techniques for structure analysis enabled correlations between initial protein conformation, fibrillar network structure formed, mechanical and adhesive properties. These results provide new insights into how protein self-assembly governs the macroscopic behavior of amyloid-based hydrogels while introducing a practical framework for investigating complex bioinspired adhesive systems.