UV-polymerizable methacrylated gelatin (GelMA)-based hydrogel containing tannic acids for wound healing.

Gelatin-based photopolymerizable methacrylate hydrogel (GelMA) is a promising biomaterial for in situ drug delivery, while aqueous extract of Punica granatum (AEPG) peel fruit rich in gallic acid and ellagic acid is used to improve wound healing. The aim of this study was to develop and analyze the healing properties of GelMA containing AEPG, gallic acid, or ellagic acid in a rodent model. GelMA hydrogels containing 5% AEPG (GelMA-PG), 1.6% gallic acid (GelMA-GA), or 2.1% ellagic acid (GelMA-EA) were produced and their mechanical properties, enzymatic degradation, and thermogravimetric profile determined. Wound closure rates, healing histological grading, and immunohistochemical counts of myofibroblasts were assessed over time. The swelling of hydrogels varied between 50 and 90%, and GelMA exhibited a higher swelling than the other groups. The GPG samples showed higher compression and Young's moduli than GelMA, GGA, and GAE. All samples degraded around 95% in 48 h. GPG and GGA significantly accelerated wound closure, improved collagenization, increased histological grading, and hastened myofibroblast differentiation in comparison to the control, GelMA, and GEA. GelMA containing AEPG (GPG) improved wound healing, and although gallic acid is the major responsible for such biological activity, a potential synergic effect played by other polyphenols present in the extract is evident.

Development and Characterization of Biointeractive Gelatin Wound Dressing Based on Extract of Punica granatum Linn.

Punica granatum Linn (pomegranate) extracts have been proposed for wound healing due to their antimicrobial, antioxidant, and anti-inflammatory properties. In this work, we designed biointeractive membranes that contain standard extracts of P. granatum for the purpose of wound healing. The used standard extract contained 32.24 mg/g of gallic acid and 41.67 mg/g of ellagic acid, and it showed high antioxidant activity (the concentration of the extract that produces 50% scavenging (IC50) 1.715 µg/mL). Compared to the gelatin-based membranes (GEL), membranes containing P. granatum extracts (GELPG) presented a higher maximal tension (p = 0.021) and swelling index (p = 0.033) and lower water vapor permeability (p = 0.003). However, no difference was observed in the elongation and elastic modulus of the two types of membranes (p > 0.05). Our wound-healing assay showed that a GELPG-treated group experienced a significant increase compared to that of the control group in their wound contraction rates on days 3 (p < 0.01), 7 (p < 0.001), and on day 14 (p < 0.001). The GELPG membranes promoted major histological changes in the dynamics of wound healing, such as improvements in the formation of granular tissue, better collagen deposition and arrangement, and earlier development of cutaneous appendages. Our results suggest that a biointeractive gelatin-based membrane containing P. granatum extracts has a promising potential application for dressings that are used to treat wounds.