Self assembly of nanostructured hexagonal cobalt dendrites: an efficient anti-coliform agent

Abstract

Highly crystalline self assemblies of three dimensional cobalt nanostructures are successfully synthesized by an electrochemical method without any template and surfactants. The cobalt nanostructures obtained by using two precursors, cobalt chloride (CoCl₂) and cobalt acetate [(CH₃–COO)₂Co], shows similar dendritic structure, but with different hierarchical architecture. The architecture of cobalt dendrites (Co-DNDs) prepared by using CoCl₂ consists of a long central trunk with hierarchical nanostructures of well aligned dendrites of length in the range 15–20 μm and sub branch is in the range 100–200 nm, while Co-DNDs prepared by using (CH₃–COO)₂Co additionally shows unique feature of hexagonal nanopoles orthogonal to main trunk. Well defined and highly crystalline Co-DNDs were obtained within thirty seconds at 15 V. Architecture of such well aligned and highly crystalline Co-DNDs with hexagonal fixtures within 30 seconds reaction is hitherto unattempted. The as-synthesized Co-DNDs showed an efficient antibacterial activity against model organisms, Bacillus subtilis NCIM 2063, Escherichia coli NCIM 2931, and fecal coliforms in a sewage waste. The inactivation of bacterial growth is due to the generation of reactive oxygen species (ROS) mediated rupture of cell membrane. An inactivation of fecal coliforms in the sewage wastewater is significant in eradicating water-borne diseases. This is an economical approach as compared to conventional and expensive metal nanoparticles like silver and gold.