Sulfidation of silver nanoparticles decreases Escherichia coli growth inhibition.

Sulfidation of metallic nanoparticles such as silver nanoparticles (AgNPs) released to the environment may be an important detoxification mechanism. Two types of AgNPs-an engineered polydisperse and aggregated AgNP powder, and a laboratory-synthesized, relatively monodisperse AgNP aqueous dispersion-were studied. The particles were sulfidized to varying degrees and characterized to determine the effect of initial AgNP polydispersity and aggregation state on AgNP sulfidation, and then exposed to Escherichia coli to determine if the degree of sulfidation of pristine AgNPs affects growth inhibition of bacteria. The extent of sulfidation was found to depend on the HS(-)/Ag ratio. However, for the same reaction times, the more monodisperse particles were fully transformed to Ag(2)S, and the polydisperse, aggregated particles were not fully sulfidized, thus preserving the toxic potential of Ag(0) in the aggregates. A higher Ag(2)S:Ag(0) ratio in the sulfidized nanoparticles resulted in less growth inhibition of E. coli over 6 h of exposure. These results suggest that the initial properties of AgNPs can affect sulfidation products, which in turn affect microbial growth inhibition, and that these properties should be considered in assessing the environmental impact of AgNPs.

[Diabetes and kidneys]. / Diabetes und Niere.

Diabetic nephropathy is the leading cause of end-stage renal disease all over the world. Diagnosis is confirmed by measuring urin albumin excretion and calculated renal function (eGFR). Once the diagnosis is confirmed there should be a search for confounding cardiovascular risk factors and even established cardiovascular disease because of the associated high cardiovascular risk. In type 1 diabetes metabolic control is the main issue. In case of renal impairment and in patients with type 2 diabetes a multifactorial approach is necessary, which consists of dietary advise, metabolic control, lowering elevated blood-pressure, cessation of smoking, ASS and lipid-lowering drug-therapy. Special drugs for the treatment of diabetes-induced renal disease are not available.