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Proceedings Paper

Comparison of Fe2O3 and Fe2CoO4 core-shell plasmonic nanoparticles for aptamer mediated SERS assays
Author(s): Haley Marks; Samuel Mabbott; Po-Jung Huang; George W. Jackson; Jun Kameoka; Duncan Graham; Gerard L. Coté
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Paper Abstract

Conjugation of oligonucleotides or aptamers and their corresponding analytes onto plasmonic nanoparticles mediates the formation of nanoparticle assemblies: molecularly bound bundles of nanoparticles which cause a measurable change in the colloid’s optical properties. Here, we present further optimization of a “SERS off” competitive binding assay utilizing plasmonic and magnetic nanoparticles for the detection of the toxin bisphenol A (BPA). The assay involves 1) a ‘target’ silver nanoparticle functionalized with a Raman reporter dye and PEGylated BPA-binding DNA aptamers, and 2) a version of the toxin BPA, bisphenol A diglycidyl ether (BADGE), PEGylated and immobilized onto a silver coated magnetic ’probe’ nanoparticle. When mixed, these target and probe nanoparticles cluster into magnetic dimers and trimers and an enhancement in their SERS spectra is observed. Upon introduction of free BPA in its native form, target AgNPs are competitively freed; reversing the nanoparticle assembly and causing the SERS signal to “turn-off” and decrease in response to the competitive binding event. The assay particles were housed inside two types of optofluidic chips containing magnetically active nickel pads, in either a straight or spotted pattern, and both Fe2O3 and Fe2CoO4 were compared as magnetic cores for the silver coated probe nanoparticle. We found that the Ag@ Fe2O3 particles were, on average, more uniform in size and more stable than Ag@ Fe2CoO4, while the addition of cobalt significantly improved the collection time of particles within the magnetic chips. Using 3D Raman mapping, we found that the straight channel design with the Ag@ Fe2O3 particles provided the most uniform nanoparticle organization, while the spotted channel design with Ag@ Fe2CoO4 demonstrated a larger SERS enhancement, and thus a lower limit of detection.

Paper Details

Date Published: 22 April 2016
PDF: 8 pages
Proc. SPIE 9722, Colloidal Nanoparticles for Biomedical Applications XI, 97220N (22 April 2016); doi: 10.1117/12.2213735
Show Author Affiliations
Haley Marks, Texas A&M Univ. (United States)
Univ. of Strathclyde (United Kingdom)
Samuel Mabbott, Univ. of Strathclyde (United Kingdom)
Po-Jung Huang, Texas A&M Univ. (United States)
George W. Jackson, BioTex, Inc. (United States)
Base Pair Biotechnologies, Inc. (United States)
Jun Kameoka, Texas A&M Univ. (United States)
Duncan Graham, Univ. of Strathclyde (United Kingdom)
Gerard L. Coté, Texas A&M Univ. (United States)


Published in SPIE Proceedings Vol. 9722:
Colloidal Nanoparticles for Biomedical Applications XI
Wolfgang J. Parak; Marek Osinski; Xing-Jie Liang, Editor(s)

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