Upcycling E-Waste: Mn/ZnO-NCs for Antibacterial and Anticancer Applications

Abstract

Manganese/zinc oxide nanocomposites (Mn/ZnO-NCs) were derived from electronic waste, utilizing Borassus flabellifer (toddy palm) and metals extracted from discarded batteries. Using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and UV-visible spectroscopy characterization of synthesized nano crystals was done to understand the structural and optical properties. UV-visible spectroscopy exhibited surface plasmon absorption peaks at 272 nm and 394 nm, confirming the formation of NCs. SEM analysis showed a uniform distribution with spherical morphology, and TEM analysis confirmed an average particle size of 20 nm, with particles ranging from 18.5 nm to 22.3 nm. EDX analysis indicated the presence of Zn, O, and Mn elements within the NCs, and XRD patterns revealed the crystalline nature with peaks corresponding to the wurtzite structure of ZnO. The antibacterial activity of Mn/ZnO-NCs was assessed against clinically relevant pathogens, including Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. The NCs exhibited significant antibacterial efficacy, with zones of inhibition ranging from 20 to 33 mm against different bacterial strains, demonstrating their potential as effective antimicrobial agents. Furthermore, using cell lines MDA-MB (triple-negative breast cancer), SKOV-3 (ovarian cancer), OVCAR-3 (ovarian adenocarcinoma), and BxPC-3 (pancreatic cancer), the antitumor potential of NCs was investigated. These NCs demonstrated notable antitumor activity, with IC₅₀ values ranging from 65.08 nM to 195.5 nM against different cancer cell lines, highlighting their promising role in cancer therapy. Overall, the results highlight the feasibility of sustainable synthesis of Mn/ZnO-NCs from electronic waste and underscore their potential applications in combating bacterial infections and cancer. This research showcases the versatility and biomedical efficacy of eco-friendly nanomaterials derived from e-waste, paving the way for future developments in green nanotechnology for healthcare applications.