Zinc oxide nanoparticle inhibits the biofilm formation of Candida glabrata: a sustainable approach to use an agro-waste of cashew apple juice.

The study describes the synthesis of zinc oxide (ZnO) nanoparticles using Anacardium occidentale cashew apple juice. The synthesized ZnO nanoparticles were characterized by UV–vis spectroscopy, FTIR spectroscopy, X-ray diffraction spectroscopy, and scanning electron microscopy. The unsophisticated observation revealed bio-reduction of Zn²⁺ by dark reddish Zn⁰ formation that settled down. The dark reddish precipitate was turned into white precipitates of ZnO nanoparticles while treated with NaOH. UV–visible spectroscopy represented the formation of ZnO nanoparticles, with an absorption band optimized at 284 nm. FTIR analysis shows the functional groups of biomolecules (protein, carbohydrate, and polyphenol) and their bio-reduction and capping processes. XRD analysis confirms the nanoparticles are highly crystalline, with poly-crystalline zinc oxides and hexagonal wurtzite types. SEM analyses revealed the flower shape of the ZnO nanoparticle's size ranges from 106.7 to 169.2 nm. The anticandidal and antibiofilm activity of ZnO nanoparticles against fluconazole-resistant clinical isolates of C. glabrata were evaluated. The ZnO nanoparticle revealed strong anticandidal activity against C. glabrata with an MIC of 48 µg/mL. The sub-MIC doses (4, 8, and 16 µg/mL) of ZnO nanoparticles showed significant antibiofilm activity against fluconazole-resistant clinical isolates of C. glabrata, with maximum biofilm reduction obtained at 16 µg/mL. Thus, the present study concludes that ZnO nanoparticles are a potential agent for the prevention of C. glabrata biofilm, especially the biofilm formed surface of a prosthetic device. [ABSTRACT FROM AUTHOR]