Electrochemically active biofilm-mediated synthesis of silver nanoparticles in water

Silver nanoparticles 1–7 nm in size were synthesized within 2 h in water by challenging an electrochemically active biofilm (EAB) with a solution containing AgNO₃ as precursor and sodium acetate as an electron donor. The electrochemically active bacteria present on the anaerobic biofilm act as a catalyst to oxidise the sodium acetate by producing electrons for the reduction of Ag⁺ ions. The high monodispersity, rapidity, and extracellular nature of this synthesis, together with the production of smaller nanoparticles that are easily separated, make this protocol highly significant in the area of nanoparticle synthesis.