Silver nanoparticles: influence of stabilizing agent and diameter on antifungal activity against Candida albicans and Candida glabrata biofilms

Abstract

Aim: The purpose of this work was to evaluate the size‐dependent antifungal activity of different silver nanoparticles (SN) colloidal suspensions against Candida albicans and Candida glabrata mature biofilms. Methods and Results: The research presented herein used SN of three different average sizes (5, 10 and 60 nm), which were synthesized by the reduction of silver nitrate through sodium citrate and which were stabilized with ammonia or polyvinylpyrrolidone. Minimal inhibitory concentration (MIC) assays were performed using the microdilution methodology. The antibiofilm activity of SN was determined by total biomass quantification (by crystal violet staining) and colony forming units enumeration. MIC results showed that all SN colloidal suspensions were fungicidal against the tested strains at very low concentrations (0·4–3·3 μg ml−1). With regard to biomass quantification, SN colloidal suspensions were very effective only against C. glabrata biofilms, achieving biomass reductions around 90% at a silver concentration of 108 μg ml−1. In general, all SN suspensions promoted significant log10 reduction of the mean number of cultivable biofilm cells after exposure to silver concentrations at or higher than 108 μg ml−1. Moreover, the results showed that the particle size and the type of stabilizing agent used did not interfere in the antifungal activity of SN against Candida biofilms. Conclusions: This study suggests that SN have antifungal therapeutic potential, but further studies are still required namely regarding formulation and delivery means. Significance and Impact of the Study: SN may contribute to the development of new strategies for the improvement of oral health and quality of life particularly of the complete denture wearers.

Green synthesis of silver nanoparticles mediated by Pulicaria glutinosa extract

“…22,23 Apart from these antimicrobial activities, Ag NPs are also known to possess antifungal, anti-inflammatory, antiviral, anti-angiogenesis, and antiplatelet properties. [24][25][26] Additionally, more recent developments have seen Ag NPs used in room spray, laundry detergent, and wall paint formulations as well as in the textile industry for clothing manufacturing. [27][28][29][30] The fascinating properties of Ag NPs mostly depend on the size and shape of the NPs.…”

Silver and gold nanoparticles synthesized from Streptomyces sp. isolated from acid forest soil with special reference to its antibacterial activity against pathogens

“…The unusual physiochemical properties of nanoparticles are attributed to their small size (\10 nm), surface structure, reactive groups and coatings [17]. AgNPs are one of the most widely used nanoparticles and notably serving as an antimicrobial agent for medical applications [18][19][20][21][22].…”

Silver Nanoparticles to Fight Candida Coinfection in the Oral Cavity

“…The effect of silver nanoparticles (SNs) with different diameters (5, 10, and 60 nm) stabilized with two types of agents, ammonia (NH 3 ) and polyvinylpyrrolidone (PVP), against C. albicans and C. glabrata mature biofilms was assessed by Monteiro et al (2012b). Although NH 3 stabilizes SNs by the formation of soluble diammine silver complexes, which trap free silver ions responsible for nanoparticle growth , the polymers of the PVP group bond on the SN surfaces through the nitrogen atom in their molecule (Kvítek et al, 2008), resulting in flocculation.…”