Development and Validation of Prostate Specific Antigen Immunoassay Platform based on Surface Enhanced Raman Spectroscopic Nanoprobe

Abstract

SERS (Surfaced-enhanced Raman Scattering) based immunoassay have drawn significant attention as the diagnostic tools for the detection of biochemical targets because of their high sensitivity, lower photobleaching and multiplexing capability. However, some troubles have been existed when diverse SERS-based immunoassay platforms are applied to practical or commercial use due to lack of validation and optimization study about each immunoassay step. In this research, we try to validate and develop a SERS-based immunoassay platform for getting reproducible and reliable assay results using sandwich immunocomplex concept with chip-based platform. Experiments were carried out by three approaches for validating immunoassay platform: (1) synthesis about three different kinds of SERS Dots and characterization with SERS signal for validating uniformity and stability of SERS Dots by single particle detection. (2) validation of nanoprobes: optimization of antibody conjugation technique and evaluating of bioactivity (3) chip substrate validation: optimization of capture antibody onto substrate, evaluating of bioactivity and non-specific binding control test. To confirm our validation approaches, we performed SERS-based immunoassay with prostate specific antigen (PSA) as a target biomarker, and then PSA could be detected high sensitivity (ca. 0.05 pg/mL LOD) with a wide dynamic range (0.0001 – 1 ng/mL). Our validated and developed SERS-based immunoassay platform will be applied to other types of biomarkers detection with any other different platforms for its step-by-step validation data.