Highly sensitive detection of thrombin

Abstract

This paper reports a highly sensitive detection of thrombin using a surface-enhanced Raman scattering (SERS)-based aptasensor. Here, magnetic beads and gold nanoparticles (Au NPs) were used as supporting substrates and sensing probes, respectively. For this purpose, 15-mer thrombin-binding aptamers (TBA15) were immobilized onto the surface of magnetic beads, and then thrombin antigen solutions and 29-mer thrombin-binding aptamer (TBA29)-conjugated Au NPs were sequentially added for the formation of sandwich immunocomplexes. Quantitative analysis was performed by monitoring the intensity variation of a characteristic SERS signal of Raman reporter molecules. Because all of the reactions occur in solution, this SERS-based immunoassay technique can solve the diffusion-limited kinetic problems on a solid substrate. The limit of detection (LOD) of thrombin, determined by SERS-based aptasensor, was estimated to be 10 pg/mL, and this low detection limit was increased by two to three orders of magnitude compared to conventional ELISA. This proposed method is expected to be a good clinical tool for the diagnosis of a thrombotic disease.