title: Antibacterial activity of glutathione-coated silver nanoparticles against Gram positive and Gram negative bacteria.
abstract: In the present paper, we study the mechanism of antibacterial activity of glutathione (GSH) coated silver nanoparticles (Ag NPs) on model Gram negative and Gram positive bacterial strains. Interference in bacterial cell replication is observed for both cellular strains when exposed to GSH stabilized colloidal silver in solution, and microbicidal activity was studied when GSH coated Ag NPs are (i) dispersed in colloidal suspensions or (ii) grafted on thiol-functionalized glass surfaces. The obtained results confirm that the effect of dispersed GSH capped Ag NPs (GSH Ag NPs) on Escherichia coli is more intense because it can be associated with the penetration of the colloid into the cytoplasm, with the subsequent local interaction of silver with cell components causing damages to the cells. Conversely, for Staphylococcus aureus, since the thick peptidoglycan layer of the cell wall prevents the penetration of the NPs inside the cytoplasm, the antimicrobial effect is limited and seems related to the interaction with the bacterial surfaces. Experiments on GSH Ag NPs grafted on glass allowed us to elucidate more precisely the antibacterial mechanism, showing that the action is reduced because of GSH coating and the limitation of the translational freedom of NPs.
authors.affiliation: Dipartimento di Chimica, Sezione di Chimica Generale, Università di Pavia, Pavia, Italy. angelo.taglietti@unipv.it
authors.forename: Angelo
authors.initials: A
authors.lastname: Taglietti
authors.forename: Yuri A
authors.initials: YA
authors.lastname: Diaz Fernandez
authors.forename: Elvio
authors.initials: E
authors.lastname: Amato
authors.forename: Lucia
authors.initials: L
authors.lastname: Cucca
authors.forename: Giacomo
authors.initials: G
authors.lastname: Dacarro
authors.forename: Pietro
authors.initials: P
authors.lastname: Grisoli
authors.forename: Vittorio
authors.initials: V
authors.lastname: Necchi
authors.forename: Piersandro
authors.initials: P
authors.lastname: Pallavicini
authors.forename: Luca
authors.initials: L
authors.lastname: Pasotti
authors.forename: Maddalena
authors.initials: M
authors.lastname: Patrini
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects*; D005978:Glutathione / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D010316:Particle Size; D012834:Silver / Q000737:chemistry / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013499:Surface Properties
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver; D005978:Glutathione