Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag+, Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium–containing citrate (as sole carbon source) and supplemented with Ag+ and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times higher than the production yield of low-Fe/Ag-EPS NPs, confirming the stimulatory effect of iron. However, relative Ag content and Ag+ ion release were higher in low-Fe/Ag-EPS NPs than in high-Fe/Ag-EPS NPs, as revealed by emission-excitation spectra by luminescent spectrometry using a novel ad hoc established phycoerythrin fluorescence–based assay. Interestingly, high and low-Fe/Ag-EPS NPs showed different and growth medium–dependent minimal inhibitory concentrations against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 15442. In addition, low-Fe/Ag-EPS NPs exert inhibition of staphylococcal and pseudomonal biofilm formation, while high-Fe/Ag-EPS NPs inhibits staphylococcal biofilm formation only. Altogether, these results, highlighting the different capability of Ag+ release, support the idea that Fe/Ag-EPS NPs produced by K. oxytoca DSM 29614 can be considered as promising candidates in the development of specific antibacterial and anti-biofilm agents. Key points • Klebsiella oxytoca DSM 29614 produces bimetal nanoparticles containing Fe and Ag. • Fe concentration in growth medium affects nanoparticle yield and composition. • Phycoerythrin fluorescence–based assay was developed to determine Ag+release. • Antimicrobial efficacy of bimetal nanoparticle parallels Ag+ions release.

Cusimano M.G., Ardizzone F., Nasillo G., Gallo M., Sfriso A., Chillura Martino D., et al. (2020). Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag+ release as determined by a novel phycoerythrin-based assay. APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, 104(14), 6325-6336 [10.1007/s00253-020-10686-w].

Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag+ release as determined by a novel phycoerythrin-based assay

Cusimano M. G.;Ardizzone F.;Nasillo G.;Chillura Martino D.;Schillaci D.;Gallo G.
2020-01-01

Abstract

Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag+, Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium–containing citrate (as sole carbon source) and supplemented with Ag+ and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times higher than the production yield of low-Fe/Ag-EPS NPs, confirming the stimulatory effect of iron. However, relative Ag content and Ag+ ion release were higher in low-Fe/Ag-EPS NPs than in high-Fe/Ag-EPS NPs, as revealed by emission-excitation spectra by luminescent spectrometry using a novel ad hoc established phycoerythrin fluorescence–based assay. Interestingly, high and low-Fe/Ag-EPS NPs showed different and growth medium–dependent minimal inhibitory concentrations against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 15442. In addition, low-Fe/Ag-EPS NPs exert inhibition of staphylococcal and pseudomonal biofilm formation, while high-Fe/Ag-EPS NPs inhibits staphylococcal biofilm formation only. Altogether, these results, highlighting the different capability of Ag+ release, support the idea that Fe/Ag-EPS NPs produced by K. oxytoca DSM 29614 can be considered as promising candidates in the development of specific antibacterial and anti-biofilm agents. Key points • Klebsiella oxytoca DSM 29614 produces bimetal nanoparticles containing Fe and Ag. • Fe concentration in growth medium affects nanoparticle yield and composition. • Phycoerythrin fluorescence–based assay was developed to determine Ag+release. • Antimicrobial efficacy of bimetal nanoparticle parallels Ag+ions release.
2020
Cusimano M.G., Ardizzone F., Nasillo G., Gallo M., Sfriso A., Chillura Martino D., et al. (2020). Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag+ release as determined by a novel phycoerythrin-based assay. APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, 104(14), 6325-6336 [10.1007/s00253-020-10686-w].
File in questo prodotto:
File Dimensione Formato  
Cusimano2020_Article_BiogenicIron-silverNanoparticle.pdf

Solo gestori archvio

Descrizione: Articolo principale
Tipologia: Versione Editoriale
Dimensione 1.41 MB
Formato Adobe PDF
1.41 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/426154
Citazioni
  • ???jsp.display-item.citation.pmc??? 4
  • Scopus 14
  • ???jsp.display-item.citation.isi??? 14
social impact