James Bardill

Hemorrhage and bacterial infection can have significant clinical consequences in the wound healing process. Here, we synthesized a zwitterionic-functionalized poly(ether-co-octylamine) (Z-pEOA) and evaluated its biocompatibility, hemostatic performance, antibacterial activity, and wound repair–relevant outcomes. Polymer structure was confirmed by 1H NMR and FTIR spectroscopy, and the polymeric nature of Z-pEOA was established by gel permeation chromatography. Zeta potential measurements demonstrated a positively charged surface with reduced net cationicity following sulfobetaine functionalization, and protein adsorption assays showed markedly attenuated nonspecific BSA binding, consistent with antifouling behavior. Extract-based biocompatibility testing demonstrated ≥70% L929 fibroblast viability in accordance with ISO 10993-5 cytotoxicity criteria, and hemolysis remained below 1%, indicating excellent hemocompatibility. Z-pEOA-impregnated gauze significantly reduced the whole-blood clotting index compared with untreated controls, indicating enhanced clot formation in vitro. Dynamic antibacterial contact testing (ASTM E2149) showed a ≥3-log reduction of Staphylococcus aureus, methicillin-resistant S. aureus, and Escherichia coli within 30 min, with sustained killing over 120 min. Live/Dead fluorescence staining supported a predominantly bactericidal, membrane-disruptive mechanism under these conditions. In a murine full-thickness wound model, topical Z-pEOA treatment did not impair macroscopic wound closure and was associated with increased epithelial thickness at both early and late time points relative to PBS controls. Collectively, these findings identify Z-pEOA as a cytocompatible, hemocompatible, broad-spectrum antibacterial, and hemostatic biomaterial in vitro, and as a nondisruptive wound-contact material in vivo, supporting its further evaluation as a multimodal wound dressing for bleeding control and infection risk reduction.

Wound infection, inadequate local hemostasis, and delayed healing remain major complications following surgery and in chronic wounds, contributing to substantial morbidity and healthcare costs. Effective wound management requires materials that simultaneously prevent infection, support hemostasis, promote tissue repair, and maintain biocompatibility. Here, we synthesized Z-pQAM, a zwitterionic-quaternary ammonium microparticle combining bactericidal and hemostatic functionalities, and evaluated its biocompatibility, antimicrobial efficacy, hemostatic performance, and wound healing effects. Fourier-transform infrared spectroscopy confirmed stepwise synthesis and quaternization. Z-pQAM exhibited >7-log10 reduction against Escherichia coli and Staphylococcus aureus and >5-log10 reduction against methicillin-resistant S. aureus at 200 mg/mL, while maintaining 50% at day 3, and enhanced collagen deposition and organization by day 12. Collectively, these findings support Z-pQAM as a cytocompatible and hemocompatible microparticle with integrated antimicrobial and hemostatic activity that improves wound healing, highlighting its potential as a multifunction topical wound dressing for clinical wound management.

Background: Diabetes mellitus is common and associated with numerous complications including diabetic foot ulcers (DFU), which affect a third of patients and are associated with high morbidity and mortality. There are limited pharmacologic treatment options available with mixed efficacy. We have developed a novel therapeutic targeting inflammation and oxidative stress by conjugating microRNA-146a to cerium oxide nanoparticles to create CNP-miR146a and have found that injectable CNP-miR146a is associated with improved wound healing in a diabetic murine model. We hypothesized that a topical formulation of CNP-miR146a would be associated with equivalent improvements in wound healing. Methods: Release tests of CNP conjugated to fluorescein isothiocyanate were performed to determine the optimal gel base for sustained release. Diabetic (db/db) mice were cutaneously wounded and treated with topical CNP-miR146a, empty gel, injectable CNP-miR146a, or injectable phosphate-buffered saline (PBS). Wound healing over time was compared between groups. Histological samples were collected and analyzed for CD45 and CD31 positivity at multiple timepoints. Results: CNP-miR146a in a topical pluronic lecithin organogel (PLO) base was associated with significantly improved wound healing compared to empty gel or injected PBS and equivalent to injected CNP-miR146a. Treatment with CNP-miR146a was also associated with decreased CD45 positivity and increased CD31 positivity, suggesting decreased inflammation and improved angiogenesis. Conclusions: Topical delivery of CNP-miR46a in a PLO base holds significant promise as a potential therapeutic for DFU and may improve patient compliance due to ease of delivery.

Objective: Elevated protease activity impairs wound healing. Cathepsin K is a cysteine protease with potent collagenolytic and elastolytic activity. This study examined the effects of odanacatib, a cathepsin K inhibitor, on wound healing in a diabetic porcine model. Additionally, it assessed whether the genetic deletion of cathepsin K improves wound healing in diabetic mice. Approach: Three cohorts of three-month-old female Yorkshire pigs (eight to ten pigs per cohort) were rendered diabetic via intravenous injections of streptozotocin (STZ, 75 mg/kg). After 4 weeks, ten full-thickness (∼300 μm) excisional skin wounds, each measuring one square inch, were created on the dorsal surface of each animal. The wounds were treated with either vehicle or odanacatib (30 or 300 ng/mm²) via intradermal injection on days 0, 3, 7, and 14. For mouse studies, diabetes was induced in cathepsin K knockout (Ctsk^–/–) and wild-type C57BL/6 mice via STZ injections, and a single full-thickness excisional wound was created on each mouse. The wounds were photographed and assessed on days 0, 7, 14, 21, and daily until complete closure. Wound healing progression was evaluated by measuring wound closure rates, CD31 expression, and histology. An in vitro scratch assay was utilized to assess the effect of odanacatib on the migration of cultured skin fibroblasts and keratinocytes under high-glucose conditions. Results: Odanacatib treatment significantly accelerated wound closure in diabetic pigs, promoting epithelialization and ECM stability. Similarly, diabetic Ctsk^–/– mice exhibited improved healing compared to wild-type controls. In vitro, odanacatib increased the migration of fibroblasts and keratinocytes under hyperglycemic conditions. Innovation and Conclusion: This study is the first to demonstrate that inhibiting cathepsin K, either genetically or pharmacologically, improves diabetic wound healing. These findings position cathepsin K as a promising therapeutic target for the treatment of chronic wounds.

Diabetes and its complications, including impaired wound healing, present a critical clinical challenge and burden for the U.S. healthcare system, with costs of over USD 13 billion annually. Hyperglycemia and chronic inflammation in diabetic wounds increase reactive oxygen species (ROS) production, inducing oxidative stress and perpetuating inflammation, which delays healing. This study investigates inflammation, oxidative stress, and the roles of cellular populations in a diabetic wound healing mouse model (db/db). Given that diabetes leads to persistent inflammation and impaired fibroblast function, we also examined how diabetes influences superoxide production in dermal fibroblasts. Blood, dermal fibroblasts, and wound tissue were collected from 12-week-old female diabetic (Db) and heterozygous (Hz) mice. Electron paramagnetic resonance (EPR) spectroscopy revealed higher superoxide levels in diabetic blood, dermal fibroblasts, and wounds compared to controls. In diabetic wounds, immunohistochemistry and flow cytometry showed increased leukocyte infiltration and reduced macrophage presence, with a higher proportion of pro-inflammatory Ly6C^hi macrophages. These results suggest that elevated superoxide production and persistent inflammation contribute to impaired fibroblast function and delayed wound healing in diabetes. By identifying the contributions of ROS and Ly6C^hi macrophages to oxidative stress and chronic inflammation, this study offers insights into therapeutic strategies. These findings highlight the importance of addressing systemic oxidative stress alongside localized inflammation to improve wound healing outcomes in diabetic patients and advance diabetic wound care strategies.

Background: Dysregulated inflammation and oxidative stress are strongly implicated in the pathogenesis of inflammatory bowel disease. We have developed a novel therapeutic that targets inflammation and oxidative stress. It is comprised of microRNA-146a (miR146a)-loaded cerium oxide nanoparticles (CNPs) (CNP-miR146a). We hypothesized that oral delivery of CNP-miR146a would reduce colonic inflammation in a mouse model of established, chronic, T cell-mediated colitis. Methods: The stability of CNP-miR146a and mucosal delivery was assessed in vitro with simulated gastrointestinal fluid and in vivo after oral gavage by quantitative real-time RT-PCR. The efficacy of orally administered CNP-miR146a was tested in mice with established colitis using the model of adoptive naïve T-cell transfer in recombinant activating gene 2 knockout (Rag2^−/−) mice. Measured outcomes included histopathology; CD45⁺ immune cell infiltration; oxidative DNA damage (tissue 8-hydroxy-2′-deoxyguanosine; 8-OHdG); expression of IL-6 and TNF mRNA and protein, and flow cytometry analysis of lamina propria Th1 and Th17 cell populations. Results: miR146a expression remained stable in simulated gastric and intestinal conditions. miR146a expression increased in the intestines of mice six hours following oral gavage of CNP-miR146a. Oral delivery of CNP-miR146a in mice with colitis was associated with reduced inflammation and oxidative stress in the proximal and distal colons as evidenced by histopathology scoring, reduced immune cell infiltration, reduced IL-6 and TNF expression, and decreased populations of CD4⁺Tbet⁺IFNg+ Th1, CD4⁺RorgT⁺IL17⁺ Th17, as well as pathogenic double positive IFNg⁺IL17⁺ T cells. Conclusions: CNP-miR146a represents a novel orally available therapeutic with high potential to advance into clinical trials.

Inflammation and oxidative stress are implicated in the pathogenesis of Crohn’s disease. Cerium oxide nanoparticle (CNP) conjugated to microRNA 146a (miR146a) (CNP-miR146a) is a novel compound with anti-inflammatory and antioxidative properties. We hypothesized that local administration of CNP-miR146a would improve colitis in a 2,4,6-Trinitrobenzenesulfonic acid (TNBS) mouse model for Crohn’s disease by decreasing colonic inflammation. Balb/c mice were instilled with TNBS enemas to induce colitis. Two days later, the mice received cellulose gel enema, cellulose gel with CNP-miR146a enema, or no treatment. Control mice received initial enemas of 50% ethanol and PBS enemas on day two. The mice were monitored daily for weight loss and clinical disease activity. The mice were euthanized on days two or five to evaluate their miR146a expression, inflammation on histology, and colonic IL-6 and TNF gene expressions and protein concentrations. CNP-miR146a enema successfully increased colonic miR146a expression at 12 h following delivery. At the end of five days from TNBS instillation, the mice treated with CNP-miR146a demonstrated reduced weight loss, improved inflammation scores on histology, and reduced gene expressions and protein concentrations of IL-6 and TNF. The local delivery of CNP-miR146a in a TNBS mouse model of acute Crohn’s colitis dramatically decreased inflammatory signaling, resulting in improved clinical disease.

Acute respiratory distress syndrome (ARDS) has approximately 40% in-hospital mortality, and treatment is limited to supportive care. Pneumonia is the underlying etiology in many cases with unrestrained inflammation central to the pathophysiology. We have previously shown that CNP-miR146a, a radical scavenging cerium oxide nanoparticle (CNP) conjugated to the anti-inflammatory microRNA(miR)-146a, reduces bleomycin- and endotoxin-induced acute lung injury (ALI) by decreasing inflammation. We therefore hypothesized that CNP-miR146a would decrease inflammation in murine infectious ALI. Mice were injured with intratracheal (IT) MRSA or saline followed by treatment with IT CNP-miR146a or saline control. Twenty-four hours post-infection, bronchoalveolar lavage fluid (BALF) and whole lungs were analyzed for various markers of inflammation. Compared to controls, MRSA infection significantly increased proinflammatory gene expression (IL-6, IL-8, TNFα, IL-1β; p < 0.05), BALF proinflammatory cytokines (IL-6, IL-8, TNFα, IL-1β; p < 0.01), and inflammatory cell infiltrate (p = 0.03). CNP-miR146a treatment significantly decreased proinflammatory gene expression (IL-6, IL-8, TNFα, IL-1β; p < 0.05), bronchoalveolar proinflammatory protein leak (IL-6, IL-8, TNFα; p < 0.05), and inflammatory infiltrate (p = 0.01). CNP-miR146a decreases inflammation and improves alveolar–capillary barrier integrity in the MRSA-infected lung and has significant promise as a potential therapeutic for ARDS.