Colloidal gold nanoparticles (AuNPs) are widely used as colorimetric sensors based on their surface plasmon resonance (SPR) properties. Researchers have been dedicated to improving the sensitivity of these colorimetric assays for decades. Here, we report a novel optical sensing strategy involving AuNPs, in which the formation of a coffee-ring deposit acts as the signal response and greatly improves the sensitivity of the assay. The mechanism of coffee-ring formation process is examined through experimental characterizations and computational simulations. Furthermore, AuNPs modified with gelsolin are applied as a coffee-ring effect assay for the selective detection of amyloid β (1-42), a typical biomarker of Alzheimer’s disease, as a proof-of-concept target. Combined with a fluorescent staining technique, the coffee-ring effect assay can be further employed in amyloid β detection and fibrillation evaluation in rat cerebrospinal fluids. Connections between the amyloid β concentration and fibrillation level in different courses of brain ischaemia are also studied.

Smart optical sensor for amyloid β detection and fibrillation evaluation on the basis of nanoparticle assemblies

251st National Meeting (2016)

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