Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of Azoimidazoles

The combination of two or more agents capable of acting in synergy has been reported as a valuable tool to fight against pathogens. Silver nanoparticles (AgNPs) present a strong antimicrobial action, although their cytotoxicity for healthy cells at active concentrations is a major concern. Azoimidaz...

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Main Authors: Ana Isabel Ribeiro, Bárbara Vieira, Daniela Dantas, Bárbara Silva, Eugénia Pinto, Fátima Cerqueira, Renata Silva, Fernando Remião, Jorge Padrão, Alice Maria Dias, Andrea Zille
Format: Article
Language:English
Published: MDPI AG 2023-03-01
Series:Pharmaceutics
Subjects:
Online Access:https://www.mdpi.com/1999-4923/15/3/926
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author Ana Isabel Ribeiro
Bárbara Vieira
Daniela Dantas
Bárbara Silva
Eugénia Pinto
Fátima Cerqueira
Renata Silva
Fernando Remião
Jorge Padrão
Alice Maria Dias
Andrea Zille
author_facet Ana Isabel Ribeiro
Bárbara Vieira
Daniela Dantas
Bárbara Silva
Eugénia Pinto
Fátima Cerqueira
Renata Silva
Fernando Remião
Jorge Padrão
Alice Maria Dias
Andrea Zille
author_sort Ana Isabel Ribeiro
collection DOAJ
description The combination of two or more agents capable of acting in synergy has been reported as a valuable tool to fight against pathogens. Silver nanoparticles (AgNPs) present a strong antimicrobial action, although their cytotoxicity for healthy cells at active concentrations is a major concern. Azoimidazole moieties exhibit interesting bioactivities, including antimicrobial activity. In this work, a class of recently described azoimidazoles with strong antifungal activity was conjugated with citrate or polyvinylpyrrolidone-stabilized AgNPs. Proton nuclear magnetic resonance was used to confirm the purity of the compounds before further tests and atomic absorption spectroscopy to verify the concentration of silver in the prepared dispersions. Other analytical techniques elucidate the morphology and stability of AgNPs and corresponding conjugates, namely ultraviolet–visible spectrophotometry, scanning transmission electron microscopy and dynamic light scattering analysis. The synergistic antimicrobial activity of the conjugates was assessed through a checkerboard assay against yeasts (<i>Candida albicans</i> and <i>Candida krusei</i>) and bacteria (<i>Staphylococcus aureus</i> and <i>Escherichia coli</i>). The conjugates showed improved antimicrobial activity against all microorganisms, in particular towards bacteria, with concentrations below their individual minimal inhibitory concentration (MIC). Furthermore, some combinations were found to be non-cytotoxic towards human HaCaT cells.
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spelling doaj.art-f611657a48cd4dfbad08ece0625d05202023-11-17T13:16:20ZengMDPI AGPharmaceutics1999-49232023-03-0115392610.3390/pharmaceutics15030926Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of AzoimidazolesAna Isabel Ribeiro0Bárbara Vieira1Daniela Dantas2Bárbara Silva3Eugénia Pinto4Fátima Cerqueira5Renata Silva6Fernando Remião7Jorge Padrão8Alice Maria Dias9Andrea Zille10Centre for Textile Science and Technology (2C2T), Department of Textile Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, PortugalCentre for Textile Science and Technology (2C2T), Department of Textile Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, PortugalDepartment of Chemistry, Chemistry Centre of University of Minho (CQUM), University of Minho, Campus of Gualtar, 4710-057 Braga, PortugalLaboratory of Microbiology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, 4050-313 Porto, PortugalLaboratory of Microbiology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, 4050-313 Porto, PortugalMolecular Oncology and Viral Pathology Group, Research Center of IPO Porto (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO Porto)/Porto Comprehensive Cancer Center (Porto.CCC), 4200-072 Porto, PortugalUCIBIO—Applied Molecular Biosciences Unit, REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira n° 228, 4050-313 Porto, PortugalUCIBIO—Applied Molecular Biosciences Unit, REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira n° 228, 4050-313 Porto, PortugalCentre for Textile Science and Technology (2C2T), Department of Textile Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, PortugalDepartment of Chemistry, Chemistry Centre of University of Minho (CQUM), University of Minho, Campus of Gualtar, 4710-057 Braga, PortugalCentre for Textile Science and Technology (2C2T), Department of Textile Engineering, University of Minho, Campus of Azurém, 4800-058 Guimarães, PortugalThe combination of two or more agents capable of acting in synergy has been reported as a valuable tool to fight against pathogens. Silver nanoparticles (AgNPs) present a strong antimicrobial action, although their cytotoxicity for healthy cells at active concentrations is a major concern. Azoimidazole moieties exhibit interesting bioactivities, including antimicrobial activity. In this work, a class of recently described azoimidazoles with strong antifungal activity was conjugated with citrate or polyvinylpyrrolidone-stabilized AgNPs. Proton nuclear magnetic resonance was used to confirm the purity of the compounds before further tests and atomic absorption spectroscopy to verify the concentration of silver in the prepared dispersions. Other analytical techniques elucidate the morphology and stability of AgNPs and corresponding conjugates, namely ultraviolet–visible spectrophotometry, scanning transmission electron microscopy and dynamic light scattering analysis. The synergistic antimicrobial activity of the conjugates was assessed through a checkerboard assay against yeasts (<i>Candida albicans</i> and <i>Candida krusei</i>) and bacteria (<i>Staphylococcus aureus</i> and <i>Escherichia coli</i>). The conjugates showed improved antimicrobial activity against all microorganisms, in particular towards bacteria, with concentrations below their individual minimal inhibitory concentration (MIC). Furthermore, some combinations were found to be non-cytotoxic towards human HaCaT cells.https://www.mdpi.com/1999-4923/15/3/926antifungalantibacterialsynergismsilver nanoparticlesstabilizing agents
spellingShingle Ana Isabel Ribeiro
Bárbara Vieira
Daniela Dantas
Bárbara Silva
Eugénia Pinto
Fátima Cerqueira
Renata Silva
Fernando Remião
Jorge Padrão
Alice Maria Dias
Andrea Zille
Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of Azoimidazoles
Pharmaceutics
antifungal
antibacterial
synergism
silver nanoparticles
stabilizing agents
title Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of Azoimidazoles
title_full Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of Azoimidazoles
title_fullStr Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of Azoimidazoles
title_full_unstemmed Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of Azoimidazoles
title_short Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of Azoimidazoles
title_sort synergistic antimicrobial activity of silver nanoparticles with an emergent class of azoimidazoles
topic antifungal
antibacterial
synergism
silver nanoparticles
stabilizing agents
url https://www.mdpi.com/1999-4923/15/3/926
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