Antibacterial and Cytotoxicity Analysis of Tellurium-Based Nanocomposites

Two major concerns that the healthcare system faces nowadays include cancer and antimicrobial resistance (AMR) to antibiotics. Nanotechnology appears as a solution, which might overcome some limitations from current medical treatments. Moreover, despite advances in nanoscale fabrication, there is a need to find alternatives to the traditional synthesis of nanomaterials, which provide a threat to both the environment and society. In this context, Green Nanotechnology is presented, with cost-effective and environmentally friendly approaches for nanoparticle synthesis. In this project, starch-mediated tellurium nanowires (TeNWs) were employed as templates for the in-situ growth of palladium and platinum oxide nanoparticles for cancer and antimicrobial applications. Specifically, the noble metal-chalcogen nanocomposites were characterized, showing antibacterial activity against AMR bacterial strains, Multidrug resistant Escherichia coli and Methicillin-resistant Staphylococcus aureus bacteria at concentrations ranging from 10 to 100 µg mL^-1 over a 24h period. Moreover, cell studies were completed with human dermal fibroblasts and melanoma cells for five days, showing no significant cytotoxic effect at nanocomposite concentrations up to 25 µg mL^-1, while triggering a dose-dependent anticancer effect in the same range. The combination of reactive oxygen species and nanocomposite shape were identified as main mechanism of action of the nanostructures.