Bacterial infection and inflammation caused by excess oxidative stress are serious challenges in chronic wound healing. The aim of this work is to investigate a wound dressing based on natural- and biowaste-derived biopolymers loaded with an herb extract that demonstrates antibacterial, antioxidant, and anti-inflammatory activities without using additional synthetic drugs. Turmeric extract-loaded carboxymethyl cellulose/silk sericin dressings were produced by esterification crosslinking with citric acid followed by freeze-drying to achieve an interconnected porous structure, sufficient mechanical properties, and hydrogel formation in situ in contact with an aqueous solution. The dressings exhibited inhibitory effects on the growth of bacterial strains that were related to the controlled release of the turmeric extract. The dressings provided antioxidant activity as a result of the radical scavenging effect on DPPH, ABTS, and FRAP radicals. To confirm their anti-inflammatory effects, the inhibition of nitric oxide production in activated RAW 264.7 macrophages was investigated. The findings suggested that the dressings could be a potential candidate for wound healing.
Green polymer-based hydrogels have been broadly applied in the pharmaceutical, medical, food and agricultural industries. Alginate/gelatine blended hydrogels loaded with guava leaf extract were prepared using the simple physical crosslinking in situ gelation method. Different blending ratios were investigated in terms of the physico-chemical properties of the hydrogels including morphology, chemical composition, mechanical properties, water absorption and release behaviour. Results indicated that gelatine content had a positive effect on loading capacity and encapsulation efficiency. Increasing gelatine content in the blends significantly improved tensile properties, particularly elongation at fracture, while the ability of the hydrogels to absorb water decreased with increasing gelatine quantity. Extract-loaded hydrogels expressed high antioxidant activity, reaching approximately 70% 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging after 30 min immersion in saline solution. Extract release from the hydrogels was controlled by swelling and polymer relaxation mechanisms according to the Korsmeyer–Peppas kinetic model. Results suggested that antioxidant-loaded alginate/gelatine hydrogels are of interest for biomedical applications.
A spray-on wound dressing has many benefits, including easy and quick administration to broad and uneven wounds, better interface with the wound site, adhesion without additional dressing, and multiple applications in a portable package. By limiting direct contact with the wound site, such a design can prevent wound damage during treatment. This study revealed a simple, one-pot synthesis of spray-on wound dressing relying on polyvinylpyrrolidone solution incorporating silver nanoparticles as a broad-spectrum antibacterial agent and wound-healing antioxidant Phyllanthus emblica extract. Silver nanoparticles were synthesized in situ using Phyllanthus emblica extract as a biogenic reducing agent. Polyvinylpyrrolidone was employed as a film-forming agent to create an adhesive hydrogel-based dressing matrix to provide moisture and establish a shielding barrier for the wound bed as well as to regulate the release of fruit extract. In vitro tests revealed that the produced dressing film had a controlled release of the fruit extract, high antioxidant activity, and a good antibacterial action against S. aureus, P. aeruginosa, E. coli, and MRSA. Additionally, a biocompatibility study has shown that both human fibroblasts and keratinocytes are unaffected by the dressing film. Based on established findings, the current spray-on solution might be a potential option for antibacterial wound dressing.
1 September 2020 in Journal of Science: Advanced Materials and Devices