Immunomodulatory Nanofibrous Modular Aerogels for Chronic Wound Healing - PROJECT SUMMARY Chronic wounds (CWs) affect ~6.5 million Americans and cost the U.S. healthcare system over ~$25 billion annually. Unlike acute wounds, CWs such as diabetic, venous, and pressure ulcers, are characterized by a prolonged inflammatory phase due to an overabundance of M1 macrophage activation and elevated pro- inflammatory cytokines, leading to poor healing outcomes. There is a pressing need for effective programming of macrophages from the M1 (pro-inflammatory) to M2 (pro-healing) phenotype to shorten the inflammation phase and accelerate healing in CWs. Our team’s recent studies have shown that the proteoglycan-4 (PRG-4) protein can modulate macrophage polarization; however, its large molecular weight (~460 kDa) limits its wound penetration, stability, and therapeutic efficacy. Our preliminary data demonstrate that PRG-4-derived peptides (C-terminal PRG4 motifs) possess improved stability and bioactivity for immunomodulation from M1 to M2 over PRG-4 protein. In addition, a lack of oxygen can cause prolonged hypoxia, affecting CWs and stalling the macrophage polarization from M1 to M2. Generally, hyperbaric oxygen therapy (HBOT) has been used to treat CWs to avoid hypoxia, systemic oxygen toxicity, and poor control over oxygen release, which remain significant limitations of HBOT treatments. To address this, we have recently developed a next-generation oxygen- generating system (OGs) composed of zein/calcium peroxide(CaO₂)/cerium oxide (CeO₂) that enables controlled, sustained oxygen release for over one month. Furthermore, current wound dressings often lack the necessary porosity for effective granulation and cell migration, which can accelerate healing. Our newly engineered porous nanofibrous microspheres (NMs) have shown >80% granulation tissue formation in a murine model within 14 days. Inspired by this, we hypothesize that a multimodal approach combining extracellular matrix-mimicking porous NMs, sustained oxygenation over one month, and a PRG-4 peptide-driven immunomodulation strategy can synergistically enhance macrophage programming from M1 to M2, thereby shortening inflammation, cell migration, vascularization, and re-epithelization in CWs within one month. The proposed work will be executed with the following aims. In Aim 1, we will engineer NMs-laden modular aerogels (NLMA) using porous NMs embedded in photo-crosslinked GelMA through simple freeze casting, resulting in tunable porosity and degradation profiles. In Aim 2, we will incorporate OGs and PRG-4 peptide into NLMA and evaluate the capability of macrophage polarization (M1 to M2) and cell compatibility under varying oxygen and PRG-4 peptide concentrations. In Aim 3, we will assess the in vivo efficacy of immunomodulatory NLMA in a murine CW model by analyzing inflammation, granulation, angiogenesis, and reepithelialization. This study aims to establish a next-generation, immunomodulatory wound dressing platform that overcome critical challenges in CW healing by resolving inflammation, sustaining oxygenation, promoting angiogenesis, and facilitating cell migration to accelerate tissue regeneration.
