Composite Hyaluronic Acid Gas-Entrapping Materials to Promote Wound Healing

Abstract

Tissue repair is often impaired in pathological states, highlighting the need for innovative wound-healing technologies. This study introduces composite hyaluronic acid gas-entrapping materials (GEMs) delivering carbon monoxide (CO) to promote wound healing in pigs. These composite materials facilitate burst release followed by sustained release of CO over 48 h. In a porcine full-thickness wound model, CO-GEMs significantly accelerated wound closure compared to the standard-of-care dressing (Tegaderm). Wound area closure with CO-GEMs was 68.6% vs 56.8% on day 14, 41.0% vs 25.1% on day 28, and 26.9% vs 11.8% on day 42, effectively reducing healing time by 14 days. Histological analysis revealed increased epithelialization and neovascularization with reduced inflammation. These findings demonstrate the potential of CO-GEMs as a topical therapeutic to enhance tissue repair in clinically relevant models, supporting further testing for wound-healing applications.

Figure 1

Carbon monoxide gas-entrapping materials (CO-GEM) were engineered for prolonged gas release to promote wound healing. (A) Schematic for the treatment of wounds using topical application of a composite foam and hydrogel GEM. Created in BioRender. Byrne, J. (2024) https://BioRender.com/r84h334. (B) Foam and hydrogel GEMs were combined to create a composite GEM placed on a full thickness porcine wound and covered with Tegaderm.

Figure 2

Foam and hydrogel CO-GEM formulations have distinct CO release kinetics. (A) Macroscopic and microscopic images of CO-GEMs. (B) CO release kinetics from each GEM as analyzed by gas chromatography (n = 3/time point).

Figure 3

CO-GEMs promote wound healing in full thickness wounds on the dorsum of pigs. (A) Treatment outline for the study where purple arrows indicate treatment with composite CO-GEMs (foams and hydrogels) and yellow-orange arrows indicate treatment with foam CO-GEMs. The treatments were transitioned from composite CO-GEMs to foam CO-GEMs due to residual hyaluronic acid hydrogel remaining and integrating into the wound. Made with BioRender.com. (B) Images of all eight wounds on control pig and pig treated with CO-GEMs at day 38. There is a visible reduction in wound size and new skin over the CO-GEM-treated animals. (C) Single images of wounds from the same position for control and CO-GEM-treated animals. (D) Quantification of wound area remaining using ImageJ for wounds on control pig and CO-GEM-treated pig (n = 8 wounds/arm). p values were quantified by unpaired t test at the specified time point. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.

Figure 4

Histologic assessment of wounds at day 42 demonstrated improvement in epithelialization and neovascularization and reduction in inflammation. (A) Representative H&E histologic sections from CO-GEM-treated and control Tegaderm-treated animals. # indicates epithelialization with keratinization, ^ indicates epithelialization without keratinization and underlying scarring, and * indicates neovascularization. The neovascularization in the control group was less mature. (B) Scoring of epithelialization, neovascularization, and inflammation for tissue sections from all 8 wounds for each animal (n = 16 sections/arm). CO-GEM-treated wounds had significantly increased epithelialization and neovascularization scores and significantly reduced inflammation scores. p values were quantified by unpaired t test.