Citric acid cross-linked honey and aloe vera gel loaded chitosan hydrogels for wound dressing applications

Abstract

Chronic wounds pose a global challenge, often requiring the use of multifunctional materials that facilitate healing while protecting against infection. The present study develops porous, biodegradable and antibacterial composite hydrogels from chitosan and polyvinyl alcohol (PVA) incorporating honey and aloe vera gel as antimicrobial agents for healing chronic wounds. Hydrogels were prepared by freeze gelation methodology, and further crosslinked with citric acid. FTIR spectra confirmed the presence of characteristic functional groups and showed a reduction in the peak intensities of O–H, N–H, and amide bands in crosslinked hydrogels. Scanning electron micrographs illustrated the clear morphological changes; citric acid crosslinked hydrogels (GG-05, GG-06, GG-08) exhibited more porous, sponge-like structures, with GG-08 achieving the highest porosity, having an average pore size of 21.28 μm. The hydrogel GG-08 demonstrated the greatest water retention capacity, reaching up to 218%, while GG-04 showed the highest degradation of 93% ± 3. The developed hydrogels exhibited better antibacterial properties, especially GG-03, GG-04, GG-07 and GG-08 had excellent activity against Gram-positive Staphylococcus aureus (S. aureus). Similarly, GG-01 and GG-05 showed excellent activities against Gram-negative bacterial strains, i.e. Escherichia coli (E. coli) and Klebsiella pneumonia (K. pneumonia). Anti-hemolytic testing confirmed the biocompatibility and non-toxic nature of hydrogels. The results demonstrated that citric acid addition has significantly improved the antibacterial potential against E. coli and K. pneumonia and also enhanced solution absorption, water retention and moisture content. Overall, these hydrogels demonstrated potential as advanced wound dressings, owing to their better moisture retention, broad-spectrum antibacterial properties and excellent biocompatibility.