Issue 6, 2020

A ratiometric electrochemiluminescence method using a single luminophore of porous g-C3N4 for the ultrasensitive determination of alpha fetoprotein

Abstract

In this work, we report a simple ratiometric electrochemiluminescence (ECL) method for ultra-sensitive immunoanalysis. A glassy carbon electrode (GCE) was modified by a mixture of porous g-C3N4 nanosheets and carbon nanotubes (CNTs). Secondary antibodies were labeled using CuS nanoparticles as the tags. After immune recognition, CuS nanoparticles in the immunocomplex were dissolved as Cu2+, which can quench the ECL of g-C3N4. The amount of Cu2+ was determined to quantify the concentration of the target antigen. To enhance the sensitivity, Cu2+ ions were firstly enriched and reduced to Cu on the surface of GCE/CNTs-g-C3N4, and the cathodic ECL of g-C3N4 was measured as the reference signal in the ratiometric ECL measurements. After applying a potential of 0.6 V (vs. Ag/AgCl) for 6 s, Cu was dissolved as Cu2+, which can quench the ECL of g-C3N4 with much higher efficiency because the freshly dissolved Cu2+ ions were distributed mainly within the Helmholtz layer of GCE/CNTs-g-C3N4. By using the ECL intensity ratio of GCE/CNTs-g-C3N4 (Cu2+) to GCE/CNTs-g-C3N4 (Cu) measured under the potentiostatic model as the signal indictor, the ratiometric ECL method was used to detect a biomarker of alpha fetoprotein with the limit of detection of 0.1 fg mL−1. It was shown that the influence of the difference in electrode modification and ECL measurement conditions on the determination of Cu2+ is suppressed greatly in the ratiometric ECL method. The combination of ratiometric ECL with electrochemical enrichment and biometallization is a useful strategy to enhance the sensitivity and reproducibility in immunoanalysis.

Graphical abstract: A ratiometric electrochemiluminescence method using a single luminophore of porous g-C3N4 for the ultrasensitive determination of alpha fetoprotein

Supplementary files

Article information

Article type
Paper
Submitted
07 Dec 2019
Accepted
14 Jan 2020
First published
15 Jan 2020

Analyst, 2020,145, 2389-2397

A ratiometric electrochemiluminescence method using a single luminophore of porous g-C3N4 for the ultrasensitive determination of alpha fetoprotein

L. Chen, X. Wang, Q. Zhang, Z. Li, Q. Kang and D. Shen, Analyst, 2020, 145, 2389 DOI: 10.1039/C9AN02470K

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