RII Track-4:NSF: Bioactive Surfaces Through Affinity Tag Protein-Polymer Conjugation

University Of Southern Mississippi, Hattiesburg MS

Investigators

Abstract

The technology addressed in this project has potential to mitigate everyday common challenges associated with interacting with surfaces. Spilling coffee on a shirt at an inconvenient time or having trepidation about touching a door handle during a global pandemic are examples of challenges that this research aims to mitigate. The surfaces that one interacts with on a daily basis are passive, requiring constant cleaning to be convenient and safe. However, interaction with surfaces would be different if surfaces were self-cleaning, antibacterial, protective, or therapeutic. Proteins provide many functions important to health, agriculture, defense, and food processing. Permanent conjugation of polymers to proteins, creating protein-polymer conjugates, is a widely used strategy to enhance protein stability for these many applications. However, challenges remain with this chemistry, including the potential of reducing protein activity through indiscriminate conjugation, or via the polymer disrupting the protein from folding into its active structure. Further, these covalent strategies contribute to material waste. Once the protein is rendered inactive, the protein, polymer, and any surface these are conjugated to will also be lost due to this permanent covalent chemistry. This project aims to develop strategies for achieving protein-polymer conjugation through a simple yet strong non-permanent interaction to produce regenerative, protein decorated ‘bioactive’ surfaces. This Research Infrastructure Improvement Track-4 EPSCoR Research Fellows (RII Track-4) project would provide a fellowship to an Assistant professor and training for a graduate student at the University of Southern Mississippi (USM). Proteins provide a myriad of functions important to health, agriculture, transportation, defense, food processing and many others. This demand for proteins has led to an increase in the desire to find strategies to incorporate these biological catalysts into synthetic systems, while providing stability and longevity of protein activity. Despite some successes in developing covalent protein-polymer conjugates to achieve this, challenges with covalent modification remain, leading to reduced or loss of protein activity resulting from protein denaturation. This project will employ scalable histidine tag (His-tag) affinity ligand chemistries, developed and routinely used for recombinant protein purification, coupled with reversible-addition fragmentation chain transfer (RAFT) polymerization as a strategy to create non-covalent protein-polymer conjugates to coat surfaces and impart bioactivity. Utilizing the His-tag for conjugation will ensure polymer attachment at the site of the N- or C-terminus of the protein, avoiding polymer attachment at the protein active site, preventing denaturation, while being amenable to almost all recombinant proteins purified with this chemistry. The non-covalent coupling chemistry will allow for the construction of protein specific bioactive surfaces, with the ease of wash removal and recoupling of active recombinant protein, creating a regenerative surface, suitable for waste reduction. Successful completion of this proof of principle approach will provide a platform technology suitable for high performing bioactive coatings. PI Clemons will be mentored by Heather Maynard, Professor of Chemistry at the University of California Los Angeles (UCLA), Co-Director of the NSF-funded BioPACIFIC MIP, and a world-leader in protein-polymer conjugation. 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.