Antibacterial and antifungal properties of dendronized silver and gold nanoparticles with cationic carbosilane dendrons

Abstract

Water soluble silver nanoparticles (AgNPs) capped with cationic carbosilane dendrons have been synthesized by direct reaction in water of dendrons, silver precursor and a reducing agent. These nanoparticles have been characterized by nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), ultraviolet spectroscopy (UV), elemental analysis, and zeta potential (ZP). The antibacterial and antifungal properties of the cationic dendrons and dendronized AgNPs and AuNPs with these dendrons have been evaluated against Gram-negative and Gram-positive bacterial -including resistant strains- and yeast strains, respectively. The results stand out for the activity of AgNPs covered with first generation dendron compared with this free dendron and corresponding dendronized AuNPs.

Dendronization of gold nanoparticles decreases their effect on human alpha-1-microglobulin

“…Thus, increased dendronization has led to a decrease in the interaction of NP with A1M, and a decrease of the effect of metal part of AuNP on protein secondary structure. This trend between nanoparticles surface and number of stabilizing dendrons has been seen with silver nanoparticles decorated with these carbosilane dendrons, where those stabilized with dendrons of first generation (smaller dendrons) released Ag ions more easily than higher generations, becoming more active as bactericides and more unstable, leading faster degradation [30].…”

Mesoporous silica nanoparticles decorated with polycationic dendrimers for infection treatment

“…Since a generation dependent cytotoxicity has been observed when dealing with polycationic dendrimers, in this approach we have selected a low non-toxic third generation [29]. Moreover, to overcome the drawback of the limited surface charges of low generation dendrimers the attachment of several dendritic molecules to the same nanoparticle is accomplished [30][31][32]. The positive charge of this nanosystem behaves as internalization agent able to penetrate the negatively charged bacteria wall.…”

Role of cationic carbosilane dendrons and metallic core of functionalized gold nanoparticles in their interaction with human serum albumin

“…Moreover, smaller dendrons would probably hamper to a lesser extent, the approach to the AuNPs surface. This trend between nanoparticle surface and number of stabilizing dendrons was seen with silver nanoparticles decorated with these carbosilane dendrons, where those stabilized with dendrons of the first generation (smaller dendrons) released Ag ions more easily than higher generations, becoming more active as bactericides and more unstable, leading to faster degradation [38]. At different pHs, 2 main transitions are observed for serum albumins [16]: normal-fast migrating at pH 3.0-4.5 (N\ \F) and normal-base at pH 6.5-8.5 (N\ \B).…”