Gellan gum-based composites hydrogel membranes with geranium and lemongrass oils for enhanced antibacterial and wound...

Currently, medical science is facing several issues such as microbial growth, prevalence of infections at wound site and resistance of common pathogens of wounds such as Staphylococcus aureus and Escherichia coli against synthetic molecules. Essential oils (EOs) are considered as promising alternative to synthetic molecules owing to antibacterial, antifungal, and antiinflammatory properties. Gellan gum based composite hydrogel membranes containing essential oils of geranium and lemongrass were prepared by solution-casting inotropic gelation method for effective wound healing. Hydrogel membranes were tested for their physicochemical properties, swelling index, in vitro antioxidant, and antibacterial potential. Solid-state characterization of prepared membranes elucidated the successful encapsulation of essential oils within the hydrogel matrix without any noticeable interaction. Scanning electron microscopy revealed smooth, uniform surface of blank ((gellan gum (G2) and gellan gum/collagen (GC7)) membrane while oil encapsulated formulations (Gellan gum/geranium oil (GG4), gellan gum/lemongrass oil (GL1), gellan gum/collagen/geranium oil (GCG4), and gellan gum/collagen/lemongrass oil (GCL1)) showed heterogeneous morphology. The antioxidant activity measured by DPPH free radical scavenging indicate that the GG4, GCL1 possessed strong % inhibition due to the presence of flavonoids and phenolic components. The GG4, GCL1 formulations revealed higher antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) (14 mm zone of inhibition) when compared to blank formulation by disc diffusion method. Furthermore, in-vivo study showed that GG4 & GCL1 membranes dramatically decrease the size of full-thickness wounds in rat models. Histological test revealed re-epithelialization, collagen and fibroblast formation along with angiogenesis. The findings from an ELISA further evidenced the wound healing potential of optimized membranes by the down regulation of pro-inflammatory cytokines i.e. (Interleukin-6) IL-6 and TNF-α (Tumor Necrosis Factor alpha). Thus, gellan gum based composite hydrogel membranes has great potential for effective wound healing and skin regeneration capacity.