Adsorption, antimicrobial and wound healing activities of biosynthesised zinc oxide nanoparticles

Using plant extracts has been interesting as possible eco-friendly methods to synthesis and stabilize different types of nanoparticles. Zinc oxide nanoparticles (ZnO-NPs) can be used as effective adsorbent due to their high surface area to volume ratio and high spontaneous adsorption properties. In this research, ZnO-NPs were synthesized and stabilized to use as an effective adsorbent material for removing two carcinogenic azo dyes: Malachite green and Congo red. It is also used as an antibacterial active material to enhance mouse skin wound healing. The fabrication and stabilization of ZnO-NPs were performed using Aloe barbadensis leaf extract. The morphology and structure of the as-synthesized ZnO-NPs were investigated by X-ray diffraction, scanning electron microscopy, Fourier transforms infrared spectroscopy and UV–Vis spectroscopy. The fabricated ZnO-NPs were applied as an adsorbent for the removal of Malachite green, a cationic azo dye, and Congo red, an anionic azo dye. The ZnO-NPs achieved adsorption efficiency of 90.7% for Malachite green azo dye within 90 min at the maximum amount of 70 mg/ml. Congo red dye was adsorbed at the efficiency of 92.30% within 120 min at 80 mg/ml maximum concentration of ZnO-NPs. Using the batch process, different parameters (time, pH, amount of adsorbent) during the adsorption process were elucidated. The results confined the applicability of ZnO-NPs as an efficient adsorbent for Malachite green and Congo red dyes. Also, the synthesised ZnO-NPs demonstrated a powerful antimicrobial activity against four types of bacterial strains of Bacillus subtilis , Klebsiella pneumonia , Bacillus licheniformis and Escherichia coli , and two types of fungi strains of Aspergillus niger and Candida albicans . The healing efficiency of mouse wound was studied using ZnO-NP/silica gel (ZnO-NP/SG) dressings due to its extensive evidence on healing property. The microscopic investigations of the wound area are reduced significantly using ZnO-NP/SG-30 ppm dressings within 11 days of observation as compared to ZnO-NPs of the control sample. These findings elaborated that as-synthesized dressing enhanced the skin repairing on the wound surface and support its usage in the future.