Journal de la nanomédecine et de la nanotechnologie

Abstrait

Nanosilver-Mediated Change in Human Intestinal Microbiota

Pranab Das, Julie AK McDonald, Elaine O Petrof, Emma Allen-Vercoe and Virginia K Walker

The widespread use of silver nanoparticles (AgNPs) has prompted studies on different species and at various trophic levels, however, little is known about possible toxicological impacts on their corresponding microbiota. Here the effects of AgNPs on a defined bacterial community established from the collected stool of a healthy donor have been investigated. The anaerobic consortium was exposed to several concentrations (0 – 200 mg/L) of AgNPs (capped; 10 nm) for 48 h. Nanosilver had a negative impact on the bacterial community as evidenced by a significant reduction (~22%) in culture-generated gas production at the two highest AgNP concentrations compared to controls, as well as significant (p<0.05) changes in fatty acid methyl ester profiles even at the lowest concentration. DNA analysis confirmed these observations showing a shift in the community structure as demonstrated by cluster analysis of PCR-denaturing gradient gel electrophoresis (DGGE) profiles, as well by phylogenetic distributions obtained from 454 pyrotag 16S rRNA gene sequencing. The bacterial assemblage was significantly (p<0.01) different in the AgNP- treatment groups compared to controls. As expected, ionic silver (AgCl; 25-200 mg/L) was also antibacterial, as shown by all four assessment methods, but its effects were distinct from the AgNP-mediated changes. Thus, nano size-dependent impacts were evident. Taken together, these experiments suggest that AgNP ingestion, either deliberate or inadvertent, could have negative consequences on our intestinal microbiota.