Structure-Property Relationships of Protein-based Block Copolymer Nanocomposites

Non-technical Abstract

This project envisions a future in which synthetic biology enables the production of tailored, biocompatible, and environmentally friendly adhesives with properties beyond those currently attainable by synthetic chemistry. This future is now possible thanks to recent breakthroughs in the preparation of recombinant protein-based biomaterials and cellulose nanocrystal reinforced nanocomposites.

The team will develop these technologies, and demonstrate them by finding adhesive solutions for the surgical reattachment of tendon to bone, a problem of significant importance to public health. For example, as many as 94% of rotator cuff repairs fail in some populations. By assembling expertise in synthetic biology, biomaterial engineering, material characterization, biomechanics, and interfaces and adhesion, the team will design and synthesize these novel surgical adhesives, with properties that no biocompatible material currently has.

Beyond broad dissemination through traditional avenues and training and education of graduate and undergraduate researchers, this work will partner with Washington University's Institute for School Partnership to translate knowledge and the excitement of discovery in this emerging area through outreach via STEM experiences and education for local K-12 teachers, students, and families.

Technical Abstract

The proposed work will demonstrate the transformative potential of a new class of recombinant protein-based biomaterials for applications requiring a complex combination of properties. The outcome of this will be sequence-structure property relationships that determine the performance of protein-based block copolymers (PBCPs) and their cellulose nanocrystals (CNCs) nanocomposites.

This project will advance the science of designing nanocomposite hydrogels and more generally the field of biomaterials by creating a generalizable platform technology for harnessing DNA templates and bacteria to produce well-defined block copolymers with desired properties from bioinspired protein motifs. In addition, this work will advance the field of nanocomposite materials design by developing (1) moieties capable of tunable interactions between nanofillers and polymer matrix chains and (2) homogenization tools that account for nanofiller surface energy and possible interactions and recrystallization of the polymer matrix in the prediction of nanocomposite mechanical properties.

Project aims include the synthesis of PBCPs where each block has a well-defined monomer sequence and structure to form (1) crystalline domains that are rigid and provide enhanced strength, (2) amorphous domains that are flexible and provide enhanced toughness, and (3) adhesive domains that allow for tunable intermolecular interactions and adhesion to surfaces. Synthetic biology allows for control of the length and sequence of each block in the copolymer.

By simultaneously tuning the chemistry of CNC surfaces and PBCP sequence, PBCP properties and interactions between CNCs and PBCPs can be controlled, thus transforming the synthesis of adhesives through the development of fully tunable nanocomposite material properties.

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.