Underwater Adhesives Produced by Chemically Induced Protein Aggregation

Barnacles convert hydrophilic proteins into an insoluble, yet aqueous, material that functions as a permanent underwater adhesive. Here, it is demonstrated that a common hydrophilic protein, bovine serum albumin, can be chemically triggered underwater to aggregate into a similar aqueous adhesive that mimics the formation of the natural adhesive. The combined action of multiple chemical denaturants initiates rapid gelation followed by further curing over time in artificial seawater. The adhesive strengths of this waterborne adhesive measured by lap shear are comparable to many bioinspired adhesives that use organic solvents and a high fraction of hydrophobic components. This approach establishes a bioinspired adhesive that can be deployed at practical scales in marine environments, produced sustainably, and sourced from low-cost materials. Applying lessons from the marine barnacle, a chemical method is developed to process commonplace proteins into insoluble materials similar to how the organism produces their permanent cement. Like in nature, control over protein aggregation enables manipulation of physical properties and ultimately underwater curing adhesives. Underwater bonds bear significant loads while using a simple solution of unmodified commercial proteins in water.image