SERS active colloidal nanoparticles for the detection of small blood biomarkers using aptamers

Haley Marks; Samuel Mabbott; George W. Jackson; Duncan Graham; Gerard L. Cote

doi:10.1117/12.2078869

12 March 2015 SERS active colloidal nanoparticles for the detection of small blood biomarkers using aptamers

Haley Marks, Samuel Mabbott, George W. Jackson, Duncan Graham, Gerard L. Cote

Proceedings Volume 9338, Colloidal Nanoparticles for Biomedical Applications X; 93381C (2015) https://doi.org/10.1117/12.2078869
Event: SPIE BiOS, 2015, San Francisco, California, United States

Abstract

Functionalized colloidal nanoparticles for SERS serve as a promising multifunctional assay component for blood biomarker detection. Proper design of these nanoprobes through conjugation to spectral tags, protective polymers, and sensing ligands can provide experimental control over the sensitivity, range, reproducibility, particle stability, and integration with biorecognition assays. Additionally, the optical properties and degree of electromagnetic SERS signal enhancement can be altered and monitored through tuning the nanoparticle shape, size, material and the colloid’s local surface plasmon resonance (LSPR). Aptamers, synthetic affinity ligands derived from nucleic acids, provide a number of advantages for biorecognition of small molecules and toxins with low immunogenicity. DNA aptamers are simpler and more economical to produce at large scale, are capable of greater specificity and affinity than antibodies, are easily tailored to specific functional groups, can be used to tune inter-particle distance and shift the LSPR, and their intrinsic negative charge can be utilized for additional particle stability.1,2 Herein, a “turn-off” competitive binding assay platform involving two different plasmonic nanoparticles for the detection of the toxin bisphenol A (BPA) using SERS is presented. A derivative of the toxin is immobilized onto a silver coated magnetic nanoparticle (Ag@MNP), and a second solid silver nanoparticle (AgNP) is functionalized with the BPA aptamer and a Raman reporter molecule (RRM). The capture (Ag@MNP) and probe (AgNP) particles are mixed and the aptamer binding interaction draws the nanoparticles closer together, forming an assembly that results in an increased SERS signal intensity. This aptamer mediated assembly of the two nanoparticles results in a 100x enhancement of the SERS signal intensity from the RRM. These pre-bound aptamer/nanoparticle conjugates were then exposed to BPA in free solution and the competitive binding event was monitored by the decrease in SERS intensity.

Citation Download Citation

Haley Marks, Samuel Mabbott, George W. Jackson, Duncan Graham, and Gerard L. Cote "SERS active colloidal nanoparticles for the detection of small blood biomarkers using aptamers", Proc. SPIE 9338, Colloidal Nanoparticles for Biomedical Applications X, 93381C (12 March 2015); https://doi.org/10.1117/12.2078869

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