Gold nanoparticles stabilized by cationic carbosilane dendrons: synthesis and biological properties

Abstract

Gold nanoparticles (AuNPs) and polycationic macromolecules are used as gene carriers. Their behaviour is dependent on several factors, such as the size and type of the framework, charge, etc. We have combined both types of systems and prepared AuNPs covered with cationic carbosilane dendrons with the aim to evaluate their biocompatibility. Water soluble dendronized cationic AuNPs were prepared following a straightforward procedure from dendrons, a gold precursor and a reducing agent in water and were characterized by H NMR, transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), ultraviolet spectroscopy (UV), and zeta potential (ZP). The biological properties of dendrons and AuNPs were determined by hemolysis, platelet aggregation and lymphocyte proliferation. These assays reflect modification of dendron properties when covering nanoparticles. For dendrons, hemolysis and platelet aggregation are generation dependent whilst, for AuNPs these properties are related to the bigger size of NPs. On the other hand, none of the systems induced lymphocyte proliferation. Selected cationic dendrons and AuNPs were chosen for gene delivery experiments employing a small interference RNA (siRNA Nef) against human immunodeficiency virus (HIV).

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

“…There was no signal from the À ÀCH 2 S group at the focal point of dendron (Figs. S3, S5 and S6), in a similar way to other cationic NPs (Peña-González et al, 2017). Finally, the zeta potential measured in aqueous solution at neutral pH attested to the stability of NPs 1Ag-3Ag at this pH, since values higher than 40 mV were observed for the three systems.…”

“…Comparison of AgNPs and AuNPs capped with the same type of dendron and synthesized following the same procedure and starting M/dendron relationship (1/1) (Peña-González et al, 2017), shows smaller sizes for AuNPs but first generation derivatives 1Ag and 1Au, which were of similar size. The size histograms also indicate higher dispersity for AgNPs (Fig.…”

“…Dendronized AgNPs were easily produced in water by the direct reaction of AgNO 3 , cationic carbosilane dendrons with a thiol moiety at the focal point HSG n (S-NMe 3 + ) m (n = 1, m = 2 (1); n = 2, m = 4 (2); n = 3, m = 8 (3)) ( Fig. S1) (Peña-González et al, 2017), and NaBH 4 acting as reducing agent (Scheme 1, Fig. 1), using a Ag/ dendron ratio of 1/1.…”

“…Herein, we report the synthesis of AgNPs capped with cationic carbosilane dendrons with the aim of exploring the combination of two microbicides systems. Their antibacterial and antifungal activity were explored and compared with those observed for free dendrons and also with analogous AuNPs covered with the same type of dendrons (Peña-González et al, 2017). For this purpose, four Gram-positive and two Gram-negative bacterial strains (including two multiresistant strains) and two strains of yeasts were selected.…”

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

“…Human serum albumin (HSA) was obtained from Sigma-Aldrich (USA) and was additionally purified by dialysis [32]. Dendronized gold nanoparticles (named 13, 14, 15) and corresponding dendrons (named 7, 8, 9, respectively) were synthesized as previously described [33]. Table 1 and Fig.…”