Size-dependent antibacterial activities of silver nanoparticles against oral anaerobic pathogenic bacteria

Abstract

Dental caries and periodontal disease are widespread diseases for which microorganism infections have been identified as the main etiology. Silver nanoparticles (Ag Nps) were considered as potential control oral bacteria infection agent due to its excellent antimicrobial activity and non acute toxic effects on human cells. In this work, stable Ag Nps with different sizes (~5, 15 and 55 nm mean values) were synthesized by using a simple reduction method or hydrothermal method. The Nps were characterized by powder X-ray diffraction, transmission electron microscopy and UV-vis absorption spectroscopy. The antibacterial activities were evaluated by colony counting assay and growth inhibition curve method, and corresponding minimum inhibitory concentration (MIC) against five anaerobic oral pathogenic bacteria and aerobic bacteria E. coli were determined. The results showed that Ag Nps had apparent antibacterial effects against the anaerobic oral pathogenic bacteria and aerobic bacteria. The MIC values of 5-nm Ag against anaerobic oral pathogenic bacteria A. actinomycetemcomitans, F. nuceatum, S. mitis, S. mutans and S. sanguis were 25, 25, 25, 50 and 50 μg/mL, respectively. The aerobic bacteria were more susceptible to Ag NPs than the anaerobic oral pathogenic bacteria. In the mean time, Ag NPs displayed an obvious size-dependent antibacterial activity against the anaerobic bacteria. The 5-nm Ag presents the highest antibacterial activity. The results of this work indicated a potential application of Ag Nps in the inhibition of oral microorganism infections.

Biogenic selenium nanoparticles synthesized by Stenotrophomonas maltophilia SeITE02 loose antibacterial and antibiofilm efficacy as a result of the progressive alteration of their organic coating layer

“…Despite this variable antimicrobial efficacy of untreated SeNPs towards the different bacterial strains tested, as a general rule MIC values increased with the progressive denaturation of the organic coating layer. These findings suggest that antimicrobial activity of SeNPs is size‐dependent, with higher inhibiting effects associated with the smallest ones, as already reported in previous studies (Lu et al ., 2013; Chudobova et al ., 2014; Zonaro et al ., 2015). Indeed, denaturation of the external organic cap which leads to a progressive increase in particle dimensions coincides with a gradual drop in antibacterial efficacy.…”

“…In conclusion, factors that are likely to concur in influencing the antimicrobial potential of biogenic metal/metalloid nanoparticles can be summarized as follows: (i) the nature of constitutive elements (Natan and Banin, 2017); (ii) the size (Lu et al ., 2013; Zonaro et al ., 2015) and (iii) the surface architecture (Verma and Stellacci, 2010). Much is still to be clarified, however, in order to elucidate in detail the nature of the external organic coating of biogenic metal nanoparticles for an actual interpretation of the intimate biocidal mechanisms.…”

Radiopacity, pH and antimicrobial activity of Portland cement associated with micro- and nanoparticles of zirconium oxide and niobium oxide

“…When added to PC, ZrO2 nanoparticles change the microstructure of the material during the hydration reaction, improving cellular proliferation and adhesion 19) . Nb2O5 nanoparticles demonstrated bioactivity and biocompatibility 20) and the capacity to increase material resistance 21) . Besides, the use of nanoparticles may increase the antibacterial activity of different materials 22) .…”

Assessment of antibacterial activity of two different sizes of colloidal silver nanoparticle (cAgNPs) against Vibrio harveyi isolated from shrimp Litopenaeus vannamei

“…Therefore, to deal with this challenge (bacterial resistance) new therapeutic strategies, such as nanoparticles, can be useful. The use of AgNPs as antibacterial agent is relatively new, and the antibacterial potential of silver nanoparticles has already been proved by many researchers (Morones et al 2005;Kim et al 2007;Sanpui et al 2008;Martínez-Castañón et al 2008;Rai et al 2009;Lago et al 2011;Chudobova et al 2013;Zhong et al 2013;Ivask et al 2014). The aim of present study was to assess the antibacterial effects of two different sizes of cAgNPs against V. harveyi.…”