Engineering Multifunctional Flowable Skin Matrices for Regeneration, Immunorestoration, and Infection Control in Hard-to-Heal Wounds - ABSTRACT Infected hard-to-heal wounds (ihws) remain a major cause of morbidity, amputation, and mortality in diabetes, driven by chronic inflammation, impaired immunity, and dominant antimicrobial-resistant pathogens Staphylococcus aureus (Sa) and Pseudomonas aeruginosa (Pa). Existing products address either healing or infection, whereas antimicrobial agents often cause toxicity, unsuitable for > 2 wk use, and prolonged antibiotics promote resistance. Royal jelly (RJ) and medical-grade honey (MGH) heal diverse wounds, hda/hdaa drive the pharmacology. RJ/MGH have hypervariable efficacies and allergic risk. Their key reparative components (ReCs)−queen-bee acid (hda), 10-hydroxydecanoic acid (hdaa), and five amino acids (R, I, L, K, D)−have short in vivo half-lives and highly variable efficacy. We recently invented multifunctional flowable scaffolds−regenerative, immunorestorative, antimicrobial skin matrices (riaMs)−self-assembles from an amphiphilic hydrogelator covalently bonding a RJ/MGH ReC [queen bee acid (hda) or 10-hydroxyl-decanoic acid (hdaa)] and a gelling-aid tripeptide of 3 amino acids (aas) selected from 5 ReC aas of wounds and RJ/MGH. riaM hydrogels are ECM-like with controlled viscoelasticity, shear-thinning, rapid liquefaction/gelation, and sustained ReC delivery. Pilot data show that select riaMs outperform RJ, MGH, and riaM moieties by promoting keratinocyte/fibroblast/endothelial survival/regeneration, restoring macrophage (Mɸ) efferocytosis and HGF production, reducing late-phase TNFα, eradicating Sa/Pa and disrupting biofilms, and rescuing diabetic ihw healing while remaining biodegradable and non-toxic. Our objective is to design, synthesize, and validate riaMs that couple regeneration, immune restoration, and infection eradication to restore diabetic ihw healing. Aim 1 discovers additional riaM leads with optimized gelation kinetics, viscoelasticity, flowability, and shear-thinning for spreadable/injectable delivery. Aim 2 identifies the best multifunctional riaMs using regenerative, immunologic, and antimicrobial assays, defines tissue penetration, biodegradation, and sustained ReC release, assesses host immune responses and immunogenicity, and validates top candidates in diabetic rat ihws and ex vivo human ihws model. Overall Impact: Successful completion will deliver biodegradable, biocompatible, multifunctional flowable skin matrices that restore healing, provide mechanistic insights into chemical/mechanical drivers of efficacy, and establish a broadly applicable platform that converts short-lived bioactives into long-acting therapeutics with strong translational potential for ihws and AMR Sa/Pa. Our team integrates complementary expertise in riaM design/synthesis and in wound-healing, antimicrobial, and immunologic assessments.
