Phytofabrication of biocompatible zinc oxide nanoparticle using Gymnema sylvestre and its potent in vitro antibacterial, antibiofilm, and cytotoxicity against human breast cancer cells (MDA-MB-231).

Abstract

The increasing incidence of breast cancer and bacterial biofilm in medical devices significantly heightens global mortality and morbidity, challenging synthetic drugs. Consequently, greener-synthesized nanomaterials have emerged as a versatile alternative for various biomedical applications, offering new therapeutic avenues. This study explores the synthesis of biocompatible zinc oxide (ZnONPs) nanoparticles using Gymnema sylvestre and its antibacterial, antibiofilm, and cytotoxic properties. Characterization of ZnONPs inferred that UV-Vis spectra exhibited a sharp peak at 370 nm. Fourier transform infrared spectroscopical analysis revealed the presence of active functional groups such as aldehyde, alkyne, cyclic alkene, sulfate, alkyl aryl ether, and Zn-O bonds. X-ray diffraction analysis results confirmed the crystalline nature of the nanoparticle. Scanning electron microscope analysis evidenced hexagonal morphology, and energy-dispersive X-ray analysis confirmed zinc content. High-resolution transmission electron microscope analysis showed hexagonal and rod-shaped ZnONPs with a size of 5 nm. Zeta potential results affirmed the stability of nanoparticles. The ZnONPs effectively inhibited gram-positive (18-20 mm) than gram-negative (12-18 mm) bacterial pathogens with lower bacteriostatic and higher bactericidal values. Biofilm inhibitory property inferred ZnONPs were more effective against gram-positive (38-94%) than gram-negative bacteria (27-86%). The concentration of ZnONPs to exert 50% biofilm-inhibitory is lower against gram-positive bacteria (179.26-203.95 μg/mL) than gram-negative bacteria (201.46-236.19 μg/mL). Microscopic visualization inferred that at 250 μg/mL, ZnONPs strongly disrupted biofilm formation, as evidenced by decreased biofilm density and altered architecture. The cytotoxicity of ZnONPs against breast cancer cells showed a dose-dependent reduction in cell viability with an IC₅₀ value of 19.4 µg/mL. AO/EB staining indicated early and late apoptotic cell death of breast cancer cells under fluorescence microscopy. The results of hemolytic activity validated the biocompatibility of the ZnONPs. Thus, the unique properties of the green-synthesized ZnONPs suggest their potential as effective drug carriers for targeted delivery in cancer therapy and the treatment of biofilm-related infections.