Avaliação in vitro do potencial antitumoral e antimicrobiano de nanocristais de óxido de zinco dopados com prata

Abstract

Cancer represents one of the major global public health problems due to its high incidence and mortality. Despite therapeutic advances, conventional oncological treatments still present significant side effects, such as immunosuppression, which compromise the patient’s immune response and increase the risk of opportunistic infections. Thus, the search for therapeutic agents with antimicrobial properties combined with antitumor activity is particularly relevant, as it may enhance clinical efficacy and reduce infectious complications during treatment. In this context, this study evaluated the in vitro antitumor and antimicrobial potential of zinc oxide (ZnO) nanocrystals doped with different silver contents. Cell viability assays demonstrated that the treatments did not reach a selectivity index (SI) ≥ 2, although ZnO:0.3Ag and ZnO:0.7Ag treatments achieved SI values of 1.53 and 1.54, respectively, for the prostate cancer cell line (PC-3). On the other hand, the lung cancer cell line (A549) showed low sensitivity, with no significant reduction in cell viability at most concentrations. Regarding antimicrobial activity, it was observed that only nanocrystals with high silver concentrations exhibited a marked effect. In particular, the formulation with 11% doping showed strong inhibition against all evaluated strains, which included Staphylococcus aureus and its methicillin-resistant mutant strain, Pseudomonas aeruginosa VIM, carbapenem-resistant Klebsiella pneumoniae, Escherichia coli, and Salmonella typhimurium. These results highlight the impact of metallic doping on biological activity, underscoring the potential of ZnO:Ag nanocrystals for integrated therapies in cancer treatment and in combating bacterial infections.