(577g) Molecular Design of Underwater Adhesives Using DOPA and Amyloid-Forming Peptide Conjugates

Adhesives capable of sticking to multiple types of surfaces in underwater and high moisture conditions are required for a large array of applications such as marine coatings, sealants, medical devices, and wet living tissue repair. Most typical industrial adhesives, however, are either developed primarily for dry applications and perform poorly in wet environments or are highly specific to particular surface types and not suitable for broad use. A viable and cost-effective strategy to address this issue is to develop generic adhesives that can be used for various surfaces in water or high moisture conditions.

One approach researchers have taken to develop new adhesives for these applications is to draw inspiration from the natural glues produced by aquatic organisms capable of strong, moisture-resistant adhesion to many different surfaces. Analysis of these natural marine glues has shown that these organisms’ abilities to adhere to a multitude of surfaces involve L-3,4-dihydroxyphenylalanine (DOPA) or functional amyloid nanostructures.

The objective of this project is to computationally design bio-inspired underwater adhesives by analyzing and combining the adhesive capabilities of DOPA and amyloid-forming peptides in wet conditions. Explicit solvent atomistic simulations can give insight into the interactions underlying surface adhesion in the presence of water and implicit coarse-grained simulations can show the formation of peptide structures, which can then be used to guide the design of DOPA-amyloid conjugates for underwater adhesion.

In this study, we begin the process of designing a DOPA-amyloid conjugate capable of generic underwater adhesion by examining the interactions between DOPA and a model surface and then by testing various DOPA-amyloid conjugate designs for their amyloid forming propensity. We first investigated the basic interactions between DOPA at a model underwater silica surface and found that DOPA readily adsorbed onto the model surface. In our DOPA-amyloid conjugate designs, the amyloid-forming peptide KLVFFAE was chosen for the initial design as it is known to self-assemble into functional amyloid nanostructures. Simulations of the conjugated DOPA-amyloid chains showed that the DOPA motifs did not interact with the rest of the chain, which leaves them free to bind to the surface. After several designs were tested for their amyloid-forming propensity, it was found that the sequence KLVFFAE-G-ddGddGdd (where d represents DOPA) was the most favorable of the currently tested designs. Future work will focus on furthering understanding of the behavior of DOPA-amyloid chains at model surfaces and how changes in the backbone of the DOPA-containing chain and in the sequence of the amyloid-forming peptide affect adhesion on the model surfaces.