Bacillus subtilis assisted assembly of gold nanoparticles into long conductive nodous ribbons

Gold nanopraticles with diameters of about 20 nm were assembled onto the surfaces of Bacillus subtilis by keeping the mixture of the nanoparicles and the bacteria in the dark without disturbance for over a month. During the aging process, the bacteria connected to each other end- to- end to form long wires and gold nanoparticles were coated compactly onto the surfaces of the wires simultaneously. The resulting composite wires were collapsed into ribbons with a width of about 1 mu m after drying in air. The ribbons present a novel structure with nodes on their backbones and have lengths of several millimeters. They are conductive and showed Ohmic behavior, which provides potential applications in the fabrication of electronic nanodevices.