CTAB stabilized cubic and spherical gold nanoparticles as highly sensitive extrinsic Raman labels (ERLs) for SERS readout in sandwich immunoassays

ANYL 134

Radha Narayanan, Radha.Narayanan@utah.edu1, Robert J. Lipert, blipert@ameslab.gov2, and Marc D. Porter, Marc.Porter@utah.edu1. (1) Center for Nanobiotechnology, University of Utah, Department of Chemistry, 315 South 1400 East, Salt Lake City, UT 84112-0850, (2) Institute for Combinatorial Discovery, USDOE-Ames Laboratory, Iowa State University, Ames, IA 50011
This presentation describes results from the first extension of particle shape in the construction of extrinsic Raman labels (ERLs) in heterogeneous sandwich immunoassays. ERLs, applied in the last step of the assay, are sensitive tags for captured antigens, with detection limits at low femtomolar levels in early disease detection (cancer biomarkers)1 and bioterrorism prevention (viruses).2 This presentation compares the detection limit obtained for ERLs based on standard spherical citrate capped gold nanoparticles (sp-cit-Au) with those for CTAB-stabilized spherical (sp-CTAB-Au) and cubic gold nanoparticles (cu-CTAB-Au) in the SERS readout for human IgG. With respect to sp-cit-Au, the detection limit is 41 times lower with sp-CTAB-Au and 336 times lower with the cu-CTAB-Au. These findings, along with assessments of underlying factors that contribute to these differences, will be discussed.

1) D. Grubisha, R. Lipert, H.Park, J. Driskell, M. Porter, Anal. Chem. 2003 75, 5936.

2) J. Driskell, K. Kwarta, R. Lipert, M. Porter, J. Neill, J. Ridpath, Anal. Chem. 2005, 19, 6147.

 

Nanomaterials in Analytical Chemistry
8:25 AM-12:25 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 335, Oral

Division of Analytical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008