Preparation, characterization and in vitro evaluation of the antimicrobial and antitumor activity of MnOx nanoparticles

Manganese oxide containing nanoparticles (MnOx NPs) have emerged as promising antimicrobial and anticancer agents due to their unique properties. However, the different initial materials and synthesis techniques often yield nanoparticles with highly different properties which limit their applications especially in the biomedical field. Thus, we aimed to explore the suitability of pyrolusite as a new and sustainable manganese mineral source for MnOx production. Moreover, we examined the effect of various synthesis methods on the physicochemical characteristics and biological activity of MnOx NPs to explore their therapeutic utilization potential against microbes and in cancer treatment. We produced MnOx NPs from a naturally occurring mineral via mechanochemical, chemical, and electrochemical processes, characterized them thoroughly, and assessed their cytotoxicity against bacteria, fungi, and human cancerous and non -cancerous cells. We verified that the synthesis method utilized to obtain MnOx NPs impacted significantly nanoparticle properties leading to distinct structural, morphological, and biological characteristics. Although none of the particles was effective against the tested bacterial strains, electrochemically produced NPs demonstrated significant antifungal activity. These nanoparticles were also the most potent anticancer agents, exhibiting cancer -selective toxicity attributed to apoptosis induction rather than altered cell proliferation or direct necrotic effects. These results are relevant for the development of effective and safe nanotherapeutics and highlight the potential of MnOx nanoparticles - obtained through carefully selected initial mineral source and adequate synthetic approach - in antimicrobial and anticancer therapy.