Immunoassay of plasmonic gold‐nanoparticle clusters: Plasmon coupling effects for Parkinson biomarker detection

Abstract

A simple signal‐on plasmonic optical assay for the detection of the Parkinson biomarker using gold‐nanoparticle clusters (AuNCs) for signal amplification is presented. This approach is based on the improvement of the optical density (OD) change of the plasmonic band of a localized surface plasmon resonance (LSPR) Au nanoparticle (AuNP) sensor interface using Au NCs conjugated antibodies. The amplification results in a 260‐fold improvement in concentration detection, from 1,000 ng/mL (unlabeled antibody) to 3.8 ng/mL (antibody‐conjugated AuNCs). The sensitivity enhancement can be ascribed to the further plasmonic coupling between the antibody‐conjugated AuNCs and the AuNPs on the LSPR interface and the enhanced amount of target molecule bound to the bioassay. This AuNCs‐assisted signal amplification strategy allows for improving the sensitivity of the plasmon‐based bioassays and can be extended to other optical‐based diagnostic technologies. Importantly, the simple detecting procedure and protocol assembly make it competitive with other existing sensing technologies such as ELISA, allowing for practical usage in clinical diagnostics.

Noninvasive Detection of Bladder Cancer Markers Based on Gold Nanomushrooms and Sandwich Immunoassays

“…The comparison with the other LSPR-based sandwich immunoassay sensing studies is shown in Table . Various types of LSPR sensors (the X part shown in the table), including the AuNPs immobilized on a glass surface, , the FO-LSPR biosensor, and the Au nanostrip, were compared with the AuNM chip. The AuNM chip possesses an ordered nanostructure array on a flexible PC substrate and shows excellent LODs.…”

Recent progress in plasmonic nanoparticle‐based biomarker detection and cytometry for the study of central nervous system disorders

“…The progressive neurodegenerative disease Parkinson's disease (PD) is the second most common neurological disorder after AD and leads to symptoms including tremors, autonomic disorders, muscle rigidity, and dyskinesia due to loss of dopaminergic neurons in the substantia nigra [75][76][77][78][79]. Sensitive and accurate PD biomarker detection may be critical for tracking PD progression, prognosis, and treatment response.…”

“…Sensitive and accurate PD biomarker detection may be critical for tracking PD progression, prognosis, and treatment response. As an example, Ko et al developed a simple and rapid plasmonic immunoassay for the detection of the PD biomarker α‐synuclein antibody in 2019 [79]. In their project, the authors developed AuNP clusters as label‐free biosensors that provided signal amplification for sensitive biomarker detection.…”

Gold Nanoparticle-Decorated Polymer Particles for High-Optical-Density Immunoassay Probes

“…To address the above challenges, efforts have been made to increase optical density by self-assembly of Au NPs. For example, immunoassay probes with enhanced optical density have been reported by forming clusters of Au NPs, , adsorbing Au NPs onto the surface of silica, magnetic particles, and polystyrene particles, , and depositing Au NPs by electrodeless plating. However, in these reports, sufficiently enhancing optical density has been challenging as a result of the sparse distribution of Au NPs on the particle surfaces.…”