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

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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

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Supplementary files

Article information


Submitted
07 Dec 2019
Accepted
14 Jan 2020
First published
15 Jan 2020

Analyst, 2020, Advance Article
Article type
Paper

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, Advance Article , DOI: 10.1039/C9AN02470K

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