MgB2 powders and bioevaluation of their interaction with planktonic microbes, biofilms, and tumor cells

Antimicrobial Activity of MgB2 Powders Produced via Reactive Liquid Infiltration Method

“…It can be observed that, from a general point of view, in the range of concentrations we tested (i.e., from 0.5 to 0.0009 mg/mL), the highest antimicrobial activity is recorded against S. aureus, followed in order by P. aeruginosa, E. coli, and C. albicans. Moreover, with the partial exception of C. albicans only, it can be highlighted that all of the MIC values obtained for the present samples produced via the RLI method are lower than the ones recently reported in an analogous experiment performed using commercially available MgB2 powders [37]. In the specific case of P. aeruginosa (ATCC 27853), the RLI sample with the best antimicrobial activity shows an MIC value of 0.062 mg/mL that is 5 times lower than the corresponding best value (0.31 mg/mL) obtained for commercial powders.…”

“…The data concerning the remaining samples and strains are plotted in Figure 7. These data show that the MBIC values are exactly the same as the MIC ones for S. aureus and C. albicans, confirming the good activity of MgB2 against both kinds of bacterial growth [37]. Additionally, the MBIC and MIC values of P. aeruginosa are practically identical, with a small increase in MBIC for samples MBNB04 and MNB05 only (see Figure7a).…”

“…On the contrary, in the case of E. coli biofilms, the inhibitory activity of all of the samples is highly reduced, with most of the MBIC values laying out of the concentration range we have explored. When compared to the commercial powders, our results show a lower antimicrobial activity against C. albicans (by a factor of 2-3) and a higher one against P. aeruginosa (by the same factor) [37]. The relationship between the MBIC results and the MgB2 phase content (see Figure 7b) supports the existence of a general correlation between high MgB2 wt.…”

“…On the other hand, it is known that an excessive B amount could interfere with the quorum sensing mechanism that is responsible for the regulation of some phenotypes (such as biofilm formation, motility, and expression of virulence factors), all of them depending on the coordination of the bacterial behavior at the population level in a density-dependent manner [35,36]. Additionally, from the point of view of MgB 2 interaction with tumor cells (HeLa and HT-29 lines), it has been recently demonstrated that this material can induce apoptosis and arrests the tumor cells in the S phase, suggesting an interference with the DNA synthesis and, consequently, with the cellular proliferation [37]. Whatever the mechanisms are at the cellular level, the anti-infectious action of MgB 2 has also been revealed in vivo, where a significant decrease in the pathogenic Escherichia coli charge in liver, spleen, and peritoneal liquid has been detected after treatments of the infected mice with this material [37,38].…”

“…Additionally, from the point of view of MgB 2 interaction with tumor cells (HeLa and HT-29 lines), it has been recently demonstrated that this material can induce apoptosis and arrests the tumor cells in the S phase, suggesting an interference with the DNA synthesis and, consequently, with the cellular proliferation [37]. Whatever the mechanisms are at the cellular level, the anti-infectious action of MgB 2 has also been revealed in vivo, where a significant decrease in the pathogenic Escherichia coli charge in liver, spleen, and peritoneal liquid has been detected after treatments of the infected mice with this material [37,38]. Finally, MgB 2 powders have been shown to be effective also against planktonic and biofilm fungi cells involved in the bio-deterioration of heritage buildings and objects [39].…”