Design and characterization of biofilm-inspired amyloid biomaterials.

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This project is jointly funded by the Biomaterials program and the Established Program to Stimulate Competitive Research (EPSCoR)BMAT: Design and characterization of biofilm-inspired amyloid biomaterials.Non-technical abstractNature produces materials with extraordinary properties, be it high strength spiderweb made of the protein silk fibroin or robust protective coat of a biofilm by fibers of the bacterial protein Curli. One of the strongest and most stable biological materials is the ‘amyloid’, which is formed from the self-association of proteins that produces densely packed, orderly protein molecules with high stability and robust material properties. The unique self-assembly processes, mechanical robustness, thermal and biocompatibility of amyloid proteins provide a rich platform for potential exploitation of bio-inspired synthetic amyloid materials for various applications. However, the relationship between protein amino acid sequence and material properties of amyloid fibers is lacking. This project brings together an interdisciplinary team with expertise in molecular biophysics, synthetic chemistry, and materials science to establish the relationships between structure, function, processing, and properties in a series of de novo peptides designed to mimic specific sequences of Curli amyloids. The fundamental understanding of structure-property relationships in the novel amyloid materials generated will serve as a platform for the development of functional biomaterials for biotechnological and pharmacological applications. As a part of this project, graduate and undergraduate students will be engaged in the research and cross-trained in faculty laboratories. Outreach efforts will be designed to engage the full diversity of Mississippi’s population, which is among the poorest in the nation and represents the highest African American population as a percentage of total population. Technical abstractAlthough amyloids are linked to many pathologies, it is becoming abundantly clear that they also play functional roles required for cellular processes in bacteria, fungi, insects, invertebrates, and humans. In bacteria, the protein CsgA Curli forms amyloid fibers that are important components of extracellular biofilms, coatings under which bacterial colonies thrive evading various environmental insults. Curli amyloids are structurally conserved cross-β-sheet structures that accommodate tightly packed interactions to provide robust material characteristics for biofilms. We hypothesize that based on the CsgA sequence as a template, ¬¬effective variant amyloid antimicrobial materials can be designed through sequence-morphology-bioactivity correlations. The proposed research will test this hypothesis and will address the question of how type and positional biases of amino acid in the sequence correlate to biochemical, morphology, and mechanical properties of the aggregates. These will be accomplished with two specific aims: The first aim will focus on the rational design, synthesis and biophysical characterization of peptides and peptide mimics along with their cellular and anti-microbial activities from cues derived from Curli. The second aim will focus on material properties such as morphology and nanomechanical stability, porosity, and ability to form hydrogels. Together, the proposed iterative approach will lay a foundation for designing amyloid materials inspired by Curli, based on sequence, structure, morphology, and microbial activity. This will enhance our current understanding of de novo amyloids in fundamental cellular processes and facilitate the development of biomaterials for pharmaceutical and biotechnology applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.