Sensitive analysis of α-synuclein by nonlinear laser wave mixing coupled with capillary electrophoresis

Abstract

Multi-photon nonlinear laser wave-mixing spectroscopy is a novel absorption-based technique that offers excellent detection sensitivity for biomedical applications, including early diagnosis and investigation of neurodegenerative diseases. α-Synuclein is linked to Parkinson's disease (PD), and characterization of its oligomers and quantification of the protein may contribute to understanding PD. The laser wave-mixing signal has a quadratic dependence on analyte concentration, and hence the technique is effective in monitoring small changes in concentration within biofluids. A wide variety of labels can be employed for laser wave-mixing detection due to its ability to detect both chromophores and fluorophores. In this investigation, two fluorophores and a chromophore are studied and used as labels for the detection of α-synuclein. Wave-mixing detection limits of PD-related protein conjugated with fluorescein isothiocyanate, QSY 35 acetic acid, succinimidyl ester, and Chromeo P503 were determined to be 1.4 × 10(-13) M, 1.4 × 10(-10) M, and 1.9 × 10(-13) M, respectively. Based on the laser probe volume used, the corresponding mass detection limits were determined to be 1.1 × 10(-23) mol, 1.1 × 10(-20) mol, and 1.5 × 10(-23) mol. This study also presents molecular-based separation and quantification of α-synuclein by laser wave mixing coupled with capillary electrophoresis.

α-Synuclein Oligomer Detection with Aptamer Switch on Reduced Graphene Oxide Electrode

“…To date, various efforts have been made to develop new techniques to sensitively detect α-Syn oligomers as a biomarker for PD diagnosis. These techniques include methods 2 of 11 based on mass spectrometry [17,18], capillary electrophoresis [19,20], nuclear magnetic resonance spectroscopy [21,22], fluorescence spectroscopy [23,24], and surface plasmon resonance [25]. Many of these techniques require costly and complex instruments and suffer from time-consuming and multistep sample preparation.…”

Ultrabright Fluorescent Silica Nanoparticles for Dual pH and Temperature Measurements

“…The number of FITC, Rb and Nb molecules encapsulated per particle is 180 ± 10, 390 ± 30 and 2500 ± 200, respectively. FRET efficiency and distance between dye molecules are given in Table S4 [25,26].…”

Capillary Electrophoresis: Trends and Recent Advances

“…Iwabuchi et al developed a CGE method for α-synuclein using nonlinear laser wave-mixing detection, which has a quadratic dependence on analyte concentration, allowing small changes in concentration to be monitored. 152 Various fluorescently labeled protein oligomers could be separated and detected down to sub-pM concentrations, making the method potentially suitable for Parkinson’s Disease diagnostics. In another method, prostate specific antigen (PSA) was isolated from serum in a way that is compatible for further analysis with CZE.…”