Label-free immunosensor based on gold nanoparticle silver enhancement

Highly sensitive immunoassay based on Raman reporter-labeled immuno-Au aggregates and SERS-active immune substrate

“…Thus, taking into account the higher stability, many researchers have to carry out the SERS-based immunoassay with small gold nanoparticles, meanwhile an additional treatment (e.g. silver stain) for SERS activation must be executed to insure the immunoassay with a higher sensitivity (Cao et al, 2003;Xu et al, 2004;Manimaran and Jana, 2007;Han et al, 2008;Li et al, 2008b;Su et al, 2009;Yang and Wang, 2009).…”

Optical detection enhancement in porous volumetric microfluidic capture elements using refractive index matching fluids

“…18 In this method, micrometre-scale silver clusters are grown on AuNP labelled biomolecular probes, resulting in large absorbance signals for the resulting assay. This approach has been previously demonstrated for enhanced optical detection of many biological targets including nucleic acids 19,20 as well as antibodies 21–24 and other proteins 25,26 with detection relying on colorimetric readers 20 , scanometric methods 19,22,26 , CCD cameras 23,24 , or direct visual inspection 27 with the naked eye to detect silver aggregate formation 18 . However, many optical immunoassays employing silver enhancement are presently limited in their utility for near-patient use.…”

Sensitive electrochemical immunosensor for platelet-derived growth factor in serum with electron transfer mediated by gold nanoparticles initiated silver enhancement

“…For the fabrication of the immunosensor, the gold electrode was first modified with an insulating SAM to block the electrode from solution with electron transfer between redox probe, Fe 3 ðCNÞ 3À 6 and the electrode. After the formation of the sandwich immuno-structure onto the electrode surface, the AuNPs could initiate silver enhancement when treated in growth solution containing Ag irons and reduction agents, such as hydroquinone [15,23]. The deposited metal silver in return, could mediate efficient electron transfer between electrode and the redox probe in the solution, resulting in a strong redox current dependent upon the concentration of analytes detected [21].…”