Green production of microalgae-based silver chloride nanoparticles with antimicrobial activity against pathogenic bacteria

Publication date: Available online 29 October 2016 Source:Enzyme and Microbial Technology Author(s): Veronica da Silva Ferreira, Mateus Eugenio Ferreira Conz, Luís Maurício T.R. Lima, Susana Frasés, Wanderley de Souza, Celso Sant’Anna Silver nanoparticles are powerful antimicrobial agents. Here, the synthesis of silver chloride nanoparticles (AgCl-NPs) was consistently evidenced from a commercially valuable microalgae species, Chlorella vulgaris. Incubation of C. vulgaris conditioned medium with AgNO3 resulted in a medium color change to yellow/brown (with UV–vis absorbance at 415nm), indicative of silver nanoparticle formation. Energy-dispersive X-ray spectroscopy (EDS) of purified nanoparticles confirmed the presence of both silver and chlorine atoms, and X-ray diffraction (XRD) showed the typical pattern of cubic crystalline AgCl-NPs. Transmission electron microscopy (TEM) showed that most particles (65%) were spherical, with average diameter of 9.8±5.7nm. Fourier transform infrared spectroscopy (FTIR) of purified nanoparticle fractions suggested that proteins are the main molecular entities involved in AgCl-NP formation and stabilization. AgCl-NPs (from 10μg/ml) decreased by 98% the growth of Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae bacterial pathogens, and had a dose-dependent effect on cell viability, which was measured by automated image-based high content screening (HCS). Ultrastructural analysis of treated bacteria ...
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research