Studies on the antifungal efficacy of histatin and amphotericin B conjugated silica coated gold nanocomposites

Abstract

Amphotericin B (Amb) is an effective drug for treating invasive fungal infections. However, the formulations currently in the market (surfactant based) elicit toxicity associated with the surfactant. In this study an amine functionalized silica capped gold nanocomposites conjugated with Amb has been designed to enhance the drug cargo to about 70% and enable a sustained release of the drug. Through DLS, zeta potential measurements, FTIR, DSC, TGA and XRD measurements the presence of gold, Si and Amb in the formulation has been established. From haemolysis assays the lowering of toxicity of Amb and to HEK cells has been confirmed. Uptake of the drug and its internalization into the C. albicans was confirmed by FITC tagging to the nanocomposite. To improve the localized delivery and faster internalization into the cell, histatin 5 was conjugated to the nanocomposite, leading to the HpepatAmbatnSips-Gps. Biological evaluation of nanocomposites revealed that Amb present in nanocomposites had MIC50 at 5.42 and#61472;and#61549;M and fluorescence microscopic analysis revealed improved localization. HpepatAmbatnSips-Gps prevented biofilm formation to a greater extent. The biological compatibility of these nanocomposite was revealed by hemolysis and MTT assay. In vivo studies to evaluate the therapeutic efficacy of the nanocomposites in disseminated candidiasis Swiss mice animal model further established the therapeutic efficacy of the nanostructures by inhibiting C.albicans and by reducing the toxic effects of Amb. Interestingly, these animals survived with an improvement in heart function and preserving the structural integrity of the tissues. Experimental in vivo studies further established the role of histatin conjugation in targeted delivery of anti-fungal drug amphotericin B. newlineKeywords: Amphotericin B, silica-gold nanocomposites, conjugation, histatin 5, localisation, In vivo studies, candidiasis, antifungal activity newline newline