In the present work, Se0 and Te0-based nanoparticles were bio-synthesized employing the selenite and tellurite-reducing capability different bacterial strains. By regulating culture conditions and exposition time, we were able to produce nanoparticles of different dimensions, between 50 and 200nm. Our results indicate that both Se0 and Te0 nanoparticles possess antimicrobial and biofilm eradication activity against Escherichia coli JM109, Pseudomonas aeruginosa PAO1 and Staphylococcus aureus ATCC 25923. Preliminary data suggests that the activity seemed to be dependent on the dimension of the nanoparticles: indeed, the highest activity was shown by the nanoparticles smaller in size. The key observation is that bacteria growth in biofilm mode didn\u2019t exhibit a higher level of resistance against the nanoparticles antimicrobial action. - See more at: http://2014.nanotechitaly.it/abstracts/se-and-te-nanoparticles-biosynthesized-by-bacteria-as-antimicrobial-agents-against-human-pathogens/#sthash.aCTfsSEX.dpu