Detail:
Abstract: Plasmonic biochips typically consist of metallic gold or silver nanostructures on substrates through which they exhibit highly sensitive collective electromagnetic oscillations depending on the surrounding dielectric materials. These biochips are known as localized surface plasmon resonance (LSPR) sensors . From a diagnostics perspective, plasmonic-enabled methodologies for routine use and high-throughput detection of disease biomarkers at low concentrations could potentially move from proof-of-principle experiments to point-of-care (POC) clinical evaluation in the near future. Herein, we introduce gold nanoparticle-cluster immunoassay that target molecules are captured via antibody-specific recognition within the hot-spot AU-LSPR biochips. By LSPR coupling of gold nanoparticle-clusters, we demonstrate an effective plasmonic protocol for conducting label-free immunoassays to detect anti-α-synuclein (anti-α-syn), which is believed to be an important pathological biomarker of Parkinson’s disease. For the early detection and screening of this Parkinson’s marker, clinical diagnosis requires a straightforward immunoassay method that can clearly discriminate between anti-α-syn levels on the order of 3.8 ng/mL (0.2 nM; molecular weight 19 KD).
