International Journal of Biological Macromolecules 251 (2023) 126243 Available online 13 August 2023 0141-8130/© 2023 Elsevier B.V. All rights reserved. Ascorbic acid-loaded gellan-g-poly(ethylene glycol) methacrylate matrix as a wound-healing material Dharavath Ravi a , G.P. Rajalekshmy a , M.R. Rekha a, * , Roy Joseph b a Division of Biosurface Technology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Poojappura, Thiruvananthapuram, Kerala, India b Polymeric Medical Devices, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Poojappura, Thiruvananthapuram, Kerala, India A R T I C L E INFO Keywords: Gellan gum Wound healing Ascorbic acid Poly (ethylene glycol) methacrylate (PEGMA) Wound care matrix ABSTRACT Ascorbic acid (AA) is one of the important biomolecules involved in all phases of wound healing. The aim of this study was to develop a new hydrogel system that offers topical delivery of ascorbic acid to wounds during wound care management. In this work, we grafted poly (ethylene glycol) methacrylate onto a renewable biopolymer gellan, and the graft copolymer (GPMA) formed was crosslinked covalently and ionically, and used as a matrix for delivering AA to the wounds. By the processes of grafting and crosslinking, the mechanical properties of the gellan increased several fold compared to mechanically weak native gellan. In vitro cytotoxicity evaluation showed that GPMA was non-cytotoxic to fbroblast cells. GPMA hydrogel matrix allowed the sustained release of AA. When AA was incorporated in GPMA, a signifcant improvement in wound closure was observed in scratch wound assay performed with keratinocytes. Since AA acts as a cofactor in collagen synthesis, the controlled delivery of AA to the wound microenvironment favors the up-regulation of colα1 gene expression. This study revealed that ascorbic acid, at a concentration of 150 μM, has a favorable impact on wound healing when tested in vitro. Overall results indicate that the GPMA matrix could be a promising material for wound healing applications. 1. Introduction A variety of renewable biopolymers are receiving greater attention than synthetic petrochemical-based polymers due to environmental concerns. Gellan gum (GG) is such a low-cost polysaccharide produced on an industrial scale with high reproducible quality. GG is a microbial anionic heteropolysaccharide produced by the bacterium Pseudomonas elodea and Sphingomonas elodea during aerobic fermentation [1,2]. The structure of GG is a straight-chain or parallel double-helix chain of four monosaccharides, 1,3-β-D-glucose, 1,4-β-D-glucuronic acid, 1,4-β-D- glucose, 1,4-α-L-rhamnose, as repeating units of each single carboxyl group or monosaccharide polymerizations [3–5]. It is commercially available in two forms, high acyl (HA) or acetylated GG and low acyl (LA) or deacetylated GG, both forming thermo-reversible gels with different mechanical properties. HA gellan gum upon cooling at a tem- perature of 65 ◦ C forms fexible or elastic hydrogel, and LA gellan gum upon cooling at 40 ◦ C forms a brittle hydrogel. The gel characteristics depend mainly on the pH, concentration, temperature, strength, and degree of substitution. The substituted form produces soft gels whilst the unsubstituted form produces hard gels [6,7]. A heterogeneous gel structure with amorphous and crystalline regions is presumed to be the aggregates and helices respectively. The best properties of GG are its malleability, stability, gelling property, textures, and high effciency [8]. GG has the characteristic to form a strong gel at low concentrations (0.01 to 0.20 %) in the presence of divalent cations (Ca 2+ , Mg 2+ ), as compared to monovalent cations such as (Na + and K + ) and its usage has expanded [9]. Gellan gum (GG) is widely used in biomedical research and many pharmaceutical applications such as gene transfection, pro- tein carrier, guided bone-regeneration material, and biological signaling [10]. Gellan gum and its combination with synthetic and natural com- pounds or polymers has been explored widely for drug delivery and wound healing owing to its non-toxic nature, gelation nature and biocompatibility [11,12]. It can be blended with a number of polymers, both natural and synthetic types. However, poor mechanical strength limits the applications of gellan gum as a matrix or as a wound healing material. Mainly, for wound healing applications gellan flms are * Corresponding author. E-mail address: rekhamr@sctimst.ac.in (M.R. Rekha). Contents lists available at ScienceDirect International Journal of Biological Macromolecules journal homepage: www.elsevier.com/locate/ijbiomac https://doi.org/10.1016/j.ijbiomac.2023.126243 Received 17 January 2023; Received in revised form 24 July 2023; Accepted 7 August 2023