Ferric plasmonic nanoparticles, aptamers, and magnetofluidic chips: toward the development of diagnostic surface-enhanced Raman spectroscopy assays

Abstract

plasmonic nanoparticles, aptamers, and magnetofluidic chips: toward the development of diagnostic surface-enhanced Raman spectroscopy assays," J. Abstract. Conjugation of aptamers and their corresponding analytes onto plasmonic nanoparticles mediates the formation of nanoparticle assemblies: molecularly bound nanoclusters that cause a measurable change in the colloid's optical properties. The optimization of a surface-enhanced Raman spectroscopy (SERS) competitive binding assay utilizing plasmonic "target" and magnetic "probe" nanoparticles for the detection of the toxin bisphenol-A (BPA) is presented. These assay nanoclusters were housed inside three types of optofluidic chips patterned with magnetically activated nickel pads, in either a straight or array pattern. Both Fe 2 O 3 and Fe 2 CoO 4 were compared as potential magnetic cores for the silver-coated probe nanoparticles. We found that the Ag@Fe 2 O 3 particles were, on average, more uniform in size and more stable than Ag@Fe 2 CoO 4 , whereas the addition of cobalt significantly improved the collection time of particles. Using Raman mapping of the assay housed within the magnetofluidic chips, it was determined that a 1 × 5 array of 50 μm square nickel pads provided the most uniform SERS enhancement of the assay (coefficient of variation ∼25%) within the magnetofluidic chip. Additionally, the packaged assay demonstrated the desired response to BPA, verifying the technology's potential to translate magnetic nanoparticle assays into a user-free optical analysis platform.

From Raman to SESORRS: moving deeper into cancer detection and treatment monitoring

“…109 This nanoparticle assembly approach can be applied to various biomolecules and has thus been exploited extensively for the development of biological detection assays. [110][111][112][113][114] Additionally, this method can be used to study biomolecular interactions, yielding significant information that may be useful in understanding cancer pathways. For example, the tumour suppressor protein, p53, plays a key role in many cancers and is regulated by mouse double minute (MDM2) protein.…”