Detection of Silver Nanoparticles by Electrochemically Activated Galvanic Exchange.

Here we report on the seemingly simple process of galvanic exchange (GE) between electrogenerated AuCl and silver nanoparticles (AgNPs). The results were obtained in the specific context of using AgNPs as labels for bioassays in paper fluidic devices. Results obtained from a combined electrochemistry and microscopy study indicate that the GE process results in recovery of only ∼5% of the total equivalents of Ag present in the system.

Paper diagnostic device for quantitative electrochemical detection of ricin at picomolar levels.

We report a paper-based assay platform for detection of ricin a chain. The paper platform is assembled by simple origami paper folding. The sensor is based on quantitative, electrochemical detection of silver nanoparticle labels linked to a magnetic microbead support via a ricin immunosandwich.