Programmable Keratinous Bio-adhesives for Recalcitrant Wound Recovery

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PROJECT SUMMARY Chronic, recalcitrant wounds and ulcers pose significant challenges to treating diabetic, obese, and elderly patients. New treatment options are needed to address rising rates; requiring a targeted approach to re-initiate the normal healing cascade. Tissue adhesives are widely used alternatives to staples and sutures. These rapidly curing polymer gels, when applied to wounds, reduce scarring, hospital time, and infection compared to standard sutures, while eliminating the need for needles and suture removal. Unfortunately, these wound treatment options offer little bioactivity; unsuitable for treating chronic wounds. Extracellular matrix (ECM) dressings (e.g. keratin) are bioactive, but offer little adhesive strength and rely on animal extractions that reduce efficacy in biocompatibility and bioactivity. Aimed at broadening available treatment options for diabetic and aging patients, this research seeks to design, build, and test novel genetically functionalized recombinant proteins with innate therapeutic bioactivity as a foundation for configurable drug delivery devices; starting with the construction of a bioactive, biocompatible tissue adhesive for early wound care in patients at high risk of wound recalcitrance. Currently, there are no engineered ECM protein tissue adhesives. As a foundational design, I will employ established genomically recoded organism polymer synthesis technologies for multiple site-specific incorporations of two non-standard amino acids (nsAAs), muco-adhesive L-dihydroxyphenylalanine (L-DOPA) and photo-cross-linkable norbornene amino acid (NorAA), each into separate epithelialization-inducing, recombinant human hair keratin heterodimer subunits, K85 and K35, respectively. Native and nsAA-keratins will be assembled into scaffolds, either via slow thiol-mediated filament assembly or rapid, on-site norbornene crosslinking, and subjected to structural characterization and cell viability assays. NorAA-DOPA-keratin scaffolds are expected to rapidly cure in seconds and present significantly enhanced adhesive strength, comparable to available dermal adhesives. In vivo characterizations of designed adhesive scaffold variants will be performed on C57BL/6J diabetic mice; e.g. healing rates, adhesive strength, morphometric analyses, and histopathological assays; comparing results to currently available tissue adhesives. I hypothesize that applying these novel keratin adhesives to recalcitrant dermal wounds will significantly enhance healing rates, block bleeding, and reduce scarring in diabetic mice.