Biogenic Metallic Nanoparticles. from Microbiological Biofactories to Nanometric Trojan Horses

Antimicrobial resistance to antibiotics (AMR) and cancer and two of the main concerns that the healthcare system should face nowadays. New alternatives are needed, and nanotechnology is rising as a powerful solution over time. Green nanotechnology is presented as a suitable answer, allowing the generation of nanostructures in a cost-effective and environmentally-friendly approach employing living organisms, such as bacteria, and biomolecules.

In this research, pathogenic bacteria and human cells were used for the synthesis of different metallic and metalloid nanoparticles with sizes between 5 and 120 nm surrounding by an organic-derived coating. The extensive characterization of the nanoparticles showed the presence of organic molecules coming from the living organisms. Bacterial tests showed an unusual selective behavior in the antimicrobial effect of bacteria-mediated nanoparticles, indicating a dose-dependent inhibition when a particular bacterial strain was treated with nanoparticles made by the same bacteria. Besides, the nanoparticles showed a robust anticancer effect while remaining biocompatible towards the healthy cell lines.

On the other hand, noble mono- and bimetallic nanoparticles synthesized by human cells were able to inhibit the growth of different cell lines. Interestingly, it was observed that after synthesis of NPs, the cells were fixed, which allowed them to resist extreme environmental conditions, like starvation for several weeks, extreme high and low pH, heat, frozen and so on. Therefore, it was observed that the production of nanoparticles allow the cells to become extremely resistant to the environment.

Therefore, it was demonstrated that microbiological agents are successfully used as a synthetic machine for the generation of different metallic/metalloid nanoparticles of different compositions with biomedical properties.