Gold nanoparticles as a promising treatment for diabetes and its complications: Current and future potentials

Diabetes and its complications represent a major cause of morbidity and mortality in diabetes patients. This review is aimed to find the potential of gold nanoparticles (AuNPs) to act as therapeutic agents for diabetes and its complications. Here, we outline the literature related to the self-therapeutic effects of AuNPs. The first goal of this review is to highlight and summarize some of the existing studies (10 years ago) in terms of several parameters such as the size of AuNPs, dose, administration route, experimental model, experimental analysis, and findings. The second goal is to describe the self-therapeutic effects of AuNPs against the pathogenesis determinants of diabetic complications. AuNPs have been found to have inhibitory effects on transforming growth factor-ß, antiglycation, antiangiogenic, anti-hyperglycemic, anti-inflammatory, and antioxidant effects. AuNPs treatment effectively disrupts multiple pathogenesis determinants in an animal model of diabetes and diabetic complications. The present review provides insight into the potential applications of AuNPs, which may help reduce the incidence of diabetes and its complications

Green synthesis of bioactive polysaccharide-capped gold nanoparticles for lymph node CT imaging.

The development of biologically targeted contrast agents for X-ray computed tomography (CT) imaging remains a major challenge. Here, we investigated a green chemistry-based synthesis of lymph node-targeted mannan-capped gold nanoparticles (M-GNPs) as a CT contrast agent. In this study, mannan was used as a reducing and stabilizing agent for gold nanoparticles (AuNPs). M-GNPs were readily internalized by antigen-presenting cells (APCs) through mannose receptors-mediated endocytosis. The M-GNPs, which had a spherical morphology, had an average diameter of 9.18±0.71nm and surface plasmon resonance (SPR) absorption spectra with maximal absorption at 522nm. The M-GNPs displayed a concentration-based X-ray attenuation property with a maximum Hounsfield unit (HU) value of 303.2±10.83. The local administration of M-GNPs led to significantly enhanced X-ray contrast for the imaging of popliteal lymph nodes. These findings demonstrated that M-GNPs can be used as biologically targeted contrast agents for CT imaging.

Synthesis, characterization and biological activity of a gold(I) triazenide complex against chronic myeloid leukemia cells and biofilm producing microorganisms

ABSTRACT The enhancement of anti-leukemia therapy and the treatment of infections caused by multidrug-resistant pathogens are major challenges in healthcare. Although a large arsenal of drugs is available, many of these become ineffective, and as a result, the discovery of new active substances occurs. Notably, triazenes (TZCs) have been consolidated as a promising class of compounds, characterized by significant biological activity, especially antiproliferative and antimicrobial properties. The aim of this study is the synthesis and characterization of a new triazenide complex of gold (I), as well as the in vitro assessment of its antiproliferative activity against the K562 cell line (Chronic Myeloid Leukemia), and antibacterial activity against bacterial isolates of biofilm-producing coagulase-negative staphylococci. The combination of TZC with gold metal tends to have a synergistic effect against all biofilm-producing isolates, with Minimum Inhibitory Concentration values (MIC) between 32 and 64 µg mL-1. It has also shown activity against K562 cell line, getting an IC50=4.96 µM. Imatinib mesylate (Glivec) was used as reference, with IC50=3.86 µM. To the best of our knowledge, this study represents the first report of the activity of a TZC complexed with gold ion in the oxidation state (I) against microorganisms that produce biofilm and K562 cells.

The mode of action of anticancer gold-based drugs: a structural perspective.

The interactions between a few representative gold-based drugs and hen egg white lysozyme were studied by X-ray crystallography. High resolution crystal structures solved for three metallodrug-protein adducts provide valuable insight into the molecular mechanism of these promising metal compounds and the inherent protein metalation processes.

Toxicity and metal speciation characterisation of waste water from an abandoned gold mine in tropical northern Australia.

The decommissioned Mount Todd gold mine, located in the wet-dry tropics of northern Australia, consists of a large waste water inventory and an acid rock drainage problem, which has the potential to impact upon freshwater ecosystems of the Edith River catchment. The toxicity of retention pond 1 (RP1) water was determined using six local freshwater species (duckweed, alga, cladoceran, snail, hydra and a fish). RP1 water was very toxic to all species, with the percentage dilution of RP1 water inhibiting 10% of organism response (IC10), or lethal to 5% of individuals (LC5), ranging from 0.007 to 0.088%. The percentage dilution of RP1 water inhibiting 50% of organism response (IC50), or lethal to 50% of individuals (LC50), ranged from 0.051% to 0.58%. Based on chemical analyses and geochemical speciation modelling of the test waters, Cu, Zn and Al were the most likely toxic components at acidic dilutions (i.e. > or =1%), while Cu and Zn were the most likely toxic components at 0.1% RP1 water, where pH was 6.5. Species sensitivity distributions (SSDs) were used to predict dilutions of RP1 water that would protect or unacceptably affect the downstream aquatic ecosystems. A dilution ratio of 1 part RP1 water to 20000 parts Edith River water (0.005% RP1 water) was calculated to be required for the protection of at least 95% of species. This information can be used in conjunction with field chemical and biological data to better predict the ecological risks of RP1 waste water downstream of the Mount Todd mine.

Biomimetic creation of hierarchical surface structures by combining colloidal self-assembly and Au sputter deposition.

Surfaces of hexagonally packed silica spheres have been functionalized with silanes containing different hydrocarbon or fluorocarbon chains. The resulting chemical and physical structures were studied to establish the effect of surface hydrophobicity on the measured contact angles on the rough surfaces. The results were used to assess the effects of surface modifications on the parameters in the Cassie equation. To achieve superhydrophobicity via a biomimetic approach, we created two-scale structures by first forming hexagonally packed SiO2 spheres, followed by Au deposition on the spheres and heat treatment to form Au nanoparticles on sphere surfaces. Contact angles over 160 degrees were achieved. This work provides improved understanding of the effect of the surface roughness and solid surface fraction on superhydrophobicity.

Dental devices; dental noble metal alloys and dental base metal alloys; designation of special controls. Final rule.

The Food and Drug Administration is amending the identification and classification regulations of gold-based alloys and precious metal alloys for clinical use and base alloys devices in order to designate a special control for these devices. FDA is also exempting these devices from premarket notification requirements. The agency is taking this action on its own initiative. This action is being taken under the Federal Food, Drug, and Cosmetic Act (the act), as amended by the Safe Medical Devices Act of 1990 (SMDA), and the Food and Drug Administration Modernization Act of 1997 (FDAMA). Elsewhere in this issue of the Federal Register, FDA is announcing the availability of the draft guidance documents that would serve as special controls for these devices.