title: Green production of microalgae-based silver chloride nanoparticles with antimicrobial activity against pathogenic bacteria.
abstract: 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 AgNO3resulted 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 by TEM revealed the abnormal arrangement of the chromosomal DNA. Our findings strongly indicated that the AgCl-NPs from C. vulgaris conditioned medium is a promising 'green' alternative for biomedical application as antimicrobials.
authors.affiliation: Laboratory of Microscopy Applied to Life Science - Lamav, National Institute of Metrology, Quality and Technology - Inmetro, Duque de Caxias, RJ 25250-020, Brazil; Post-graduation Program on Translational Biomedicine - Biotrans, Duque de Caxias, RJ 25071-202, Brazil.
authors.forename: Veronica
authors.initials: V
authors.lastname: da Silva Ferreira
authors.affiliation: Laboratory of Microscopy Applied to Life Science - Lamav, National Institute of Metrology, Quality and Technology - Inmetro, Duque de Caxias, RJ 25250-020, Brazil; Post-graduation Program on Translational Biomedicine - Biotrans, Duque de Caxias, RJ 25071-202, Brazil.
authors.forename: Mateus Eugenio
authors.initials: ME
authors.lastname: ConzFerreira
authors.affiliation: Laboratory of Pharmaceutical Biotechnology, School of Pharmacy, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ 21949-900, Brazil.
authors.forename: Luís Maurício T R
authors.initials: LM
authors.lastname: Lima
authors.affiliation: National Institute of Science and Technology for Structural Biology and Bioimaging, Rio de Janeiro, RJ 21949-900, Brazil; Laboratory of Cellular Ultrastructure Hertha Meyer, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ 21949-900, Brazil.
authors.forename: Susana
authors.initials: S
authors.lastname: Frasés
authors.affiliation: National Institute of Science and Technology for Structural Biology and Bioimaging, Rio de Janeiro, RJ 21949-900, Brazil; Laboratory of Cellular Ultrastructure Hertha Meyer, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ 21949-900, Brazil; Post-graduation Program on Translational Biomedicine - Biotrans, Duque de Caxias, RJ 25071-202, Brazil.
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
authors.affiliation: Laboratory of Microscopy Applied to Life Science - Lamav, National Institute of Metrology, Quality and Technology - Inmetro, Duque de Caxias, RJ 25250-020, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging, Rio de Janeiro, RJ 21949-900, Brazil; Post-graduation Program on Translational Biomedicine - Biotrans, Duque de Caxias, RJ 25071-202, Brazil. Electronic address: celso.santanna@gmail.com.
authors.forename: Celso
authors.initials: C
authors.lastname: Sant'Anna
mesh_terms: D000890:Anti-Infective Agents / Q000378:metabolism* / Q000494:pharmacology*; D048408:Chlorella vulgaris / Q000378:metabolism; D055772:Green Chemistry Technology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000648:ultrastructure; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D058086:Microalgae / Q000378:metabolism; D036103:Nanotechnology; D018030:Silver Compounds / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000648:ultrastructure
chemical_list: D000890:Anti-Infective Agents; D018030:Silver Compounds; C037548:silver chloride
keywords: Antimicrobial activity; Chlorella vulgaris; Green synthesis; Microalgae; Silver chloride nanoparticles