Selenite-Incorporated Amorphous Calcium–Magnesium Carbonate Nanoparticles Reduce Bacterial Growth

Amorphous calcium carbonate (ACC) is a nontoxic and degradable nanomaterial. ACC can be synthesized using the coprecipitation technique, which enables the incorporation of ions into its amorphous structure. Although ACC has been investigated for various applications, such as wastewater treatment, in vivo imaging, and drug delivery, its antibacterial properties have not been explored. Considering the extraordinary capability of bacteria to adapt antimicrobial strategies, as well as the extensive burden of bacteria-induced problems on healthcare systems and the world economy, the need for effective antibacterial agents is becoming a pressing issue. Herein, we introduced selenite-incorporated magnesium-stabilized amorphous calcium carbonate (ACMC) nanoparticles as a sustainable antibacterial material. For the first time, we demonstrated that selenite ions could be incorporated into ACMC nanoparticles while preserving the amorphous structure. Antibacterial activity analysis showed that selenite-incorporated ACMC (Se-ACMC) nanoparticles at 1 g/L concentration could significantly reduce the growth of Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria strains within 24 h of interaction. As an important observation, even the lowest selenite incorporation (4.38 ± 0.19 mg selenium per g of nanoparticles) led to a more than 3-log reduction in the number of S. epidermidis colonies. Additionally, the antibacterial activity was enhanced with an increase in the amount of incorporated selenite. These results indicated that ion-incorporated ACMC nanoparticles can pave the way for applications as antibacterial agents.