Analytical Sciences

A Novel Gold Nanoprobe for a Simple Electrochemiluminescence Determination of a Prostate-specific Antigen Based on a Peptide Cleavage Reaction

Zhejian LI, Shumin WANG, Xuemei FAN, Baoyue CAO, and Chunsheng ZHOU

Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources, College of Chemical Engineering and Modern Materials, Shangluo University, Shangluo, 726000, P. R. China

A novel gold nanoprobe for a sensitive and simple determination of a prostate-specific antigen (PSA) was designed on the basis of homogeneous detection and a peptide cleavage reaction. The gold nanoprobe (AuNPs-peptide-Ru1) consisted of a specific peptide tagged with a ruthenium(II) complex (Ru1) and gold nanoparticles (AuNPs) conjugated with the peptide via the strong Au–S bond between the AuNPs surface and the thiol group of the peptide. The electrochemiluminescence (ECL) enzymatic-cleavage-reaction-based bioanalytic system based on homogeneous detection has overcome shortcomings from a complicated fabrication process of traditional electrodes. In the presence of the target PSA, it specifically cleaved the peptide of the AuNPs-peptide-Ru1, and the ECL signal substance (Ru1) part dissociated from AuNPs-peptide-Ru1. This resulted in an increase in the ECL intensity. The ECL biosensor could detect PSA concentrations in the range from 1.0 × 10⁻¹² to 1.0 × 10⁻⁹ g/mL, the detection limit was 4.0 × 10⁻¹³ g/mL. The assay with the advantages of a simple method for PSA was selective and fast. It is superior to the immunoassay, and is a promising strategy to develop biosensors based on enzymatic cleavage including electrochemistry and optics.

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