Synthesis and Stabilization of Gold Nanoparticles Using Water-Soluble Synthetic and Natural Polymers

Abstract

Gold nanoparticles (AuNPs) were synthesized and stabilized using the one-pot method and growth seeding, through utilization of synthetic polymers, including poly(N-vinylpyrrolidone) (PVP), poly(ethylene glycol) (PEG), and poly(vinylcaprolactame) (PVCL), as well as natural polysaccharides, including gellan, welan, pectin, and κ-carrageenan. The absorption spectra, average hydrodynamic size, ζ-potential, and morphology of the gold nanoparticles were evaluated based on various factors, such as polymer concentration, molecular mass of polymers, temperature, and storage time. The optimal polymer concentration for stabilization of AuNPs was found to be 4.0 wt % for PVP, 0.5 wt % for gellan, and 0.2 wt % for pectin, welan, and κ-carrageenan. The values of the ζ-potential of polymer-stabilized AuNPs show that their surfaces are negatively charged. Most of the AuNPs are polydisperse particles, though very monodisperse AuNPs were detected in the presence of a 0.5 wt % gellan solution. At a constant polymer concentration of PVP (4 wt %), the average size of the PVP–AuNPs decreased with the decrease of molecular weight, and in the following order: PVP 350 kDa (~25 nm) > PVP 40 kDa (~8 nm) > PVP 10 kDa (~4 nm). The combination of Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy revealed that the functional groups of polymers that are responsible for stabilization of AuNPs are lactam ring in PVP, carboxylic groups in gellan and welan, esterified carboxylic groups in pectin, and SO2 groups in κ-carrageenan. Viscometric and proton nuclear magnetic resonance (1H NMR) spectroscopic measurements showed that the temperature-dependent change in the size of AuNPs, and the gradual increase of the intensity of AuNPs at 550 nm in the presence of gellan, is due to the rigid and disordered conformation of gellan that affects the stabilization of AuNPs. The AuNPs synthesized in the presence of water-soluble polymers were stable over a period of 36 days. Preliminary results on the synthesis and characterization of gold nanorods stabilized by polymers are also presented.

Evaluation of the Antioxidant Capacities of Antarctic Macroalgae and Their Use for Nanoparticles Production

“…The Z potential values obtained for the samples are collected in Table 2 , where it can be seen that the particles carry a negative electrostatic surface charge. This result suggests the involvement of the anionic polysaccharides present in the extract in the stabilization process of the nanoparticles, since the negative values obtained are in accordance with other studies where marine polysaccharides were employed for the synthesis of nanoparticles [ 25 , 26 ]. It is interesting to highlight the values obtained for the nanoparticles synthesized since, according to Z potential guidelines, nanoparticle dispersions with Z potential values ˃±30 mV are highly stable [ 27 ].…”

A Comparison of the Genotoxic Effects of Gold Nanoparticles Functionalized with Seven Different Ligands in Cultured Human Hepatocellular Carcinoma Cells

“…GNP characterization showed that spherical 18 nm GNPs were successfully synthesized and capped with the various ligands [ 37 , 38 ]. Studies have shown that the interaction of GNPs with polymers impacts the size, stability, and distribution of GNPs; therefore, the particle stability was assessed in possible various cell culture conditions [ 38 , 39 ]. The obtained results showed that the particles were stable in cell culture environments allowing for chronic GNP-ligand exposure to the HepG2 cells.…”

Hybrid Hydrogels with Stimuli-Responsive Properties to Electric and Magnetic Fields

“…Au NP have been successfully synthesized within many natural (e.g., pectin and κ-carrageenan) and synthetic (e.g., poly(N-vinylpyrrolidone) (PVP), PEG, etc.) hydrogels following the in situ method [47]. Incorporation of CP inside a hydrogel can also be achieved by in situ polymerization.…”