Silver colloidal nanoparticles: effect on matrix composition and structure of C andida albicans and C andida glabrata biofilms

Aim The aim of this study was to assess the effect of different silver nanoparticles ( SN ) concentrations on the matrix composition and structure of C andida albicans and C andida glabrata biofilms. Methods and Results C andida biofilms were developed in 6‐well microtiter plates during 48 h. After, these biofilms were exposed to 13·5 or 54 μg  SN  ml −1 for 24 h. Then, extracellular matrices were extracted from biofilms and analysed chemically in terms of proteins, carbohydrates and DNA . To investigate the biofilm structure, scanning electron microscopy ( SEM ) and epifluorescence microscopy were used. SN interfered with the matrix composition of C andida biofilms tested in terms of protein, carbohydrate and DNA , except for the protein content of C . albicans biofilm. By SEM , C andida biofilms treated with SN revealed structural differences, when compared with the control groups. Further, SN showed a trend of agglomeration within the biofilms. Epifluorescence microscopy images suggest that SN induced damage on cell walls of the C andida isolates tested. Conclusions In general, irrespective of concentration, SN affected the matrix composition and structure of C andida biofilms and these findings may be related to the mechanisms of biocide action of SN . Significance and Impact of the Study This study reveals new insights about the behaviour of SN when in contact with C andida biofilms. SN may contribute to the development of therapies to prevent or control C andida infections.