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Ratiometric ultrasensitive electrochemical immunosensor based on redox substrate and immunoprobe
1Department of Chemistry, Capital Normal University, Beijing 100048, China.
Insights
This study introduces a novel ratiometric electrochemical immunosensor for detecting human immunoglobulin G (IgG). The sensor utilizes unique nanocomposites, achieving high sensitivity and a wide linear range for potential clinical diagnosis applications.
Area of Science:
- Electrochemistry
- Nanotechnology
- Biomedical Engineering
Background:
- Development of sensitive and reliable biosensors is crucial for early disease detection.
- Electrochemical immunosensors offer advantages in sensitivity and cost-effectiveness.
- Ratiometric detection strategies can enhance sensor stability and accuracy.
Purpose of the Study:
- To develop a novel ratiometric electrochemical immunosensor for the sensitive detection of human immunoglobulin G (IgG).
- To synthesize and characterize novel carboxymethyl cellulose-Au-Pb2+ (CMC-Au-Pb2+) and carbon-Au-Cu2+ (C-Au-Cu2+) nanocomposites for redox substrate and immunoprobe applications.
- To evaluate the analytical performance of the proposed immunosensor, including its linear range and limit of detection.
Main Methods:
- Synthesis of CMC-Au-Pb2+ and C-Au-Cu2+ nanocomposites.
- Fabrication of a sandwich-type electrochemical immunosensor.
- Ratiometric measurement of current signals (Iprobe/Issubstrate) at specific potentials (-0.45 V and 0.15 V).
- Analysis of human immunoglobulin G (IgG) using the developed sensor.
Main Results:
- The synthesized nanocomposites exhibited strong current signals, suitable for redox substrate and immunoprobe functions.
- A linear relationship was observed between the signal ratio (Iprobe/Issubstrate) and the logarithm of IgG concentration (Lg C(IgG)).
- The immunosensor demonstrated a wide linear range (1 fg mL-1 to 100 ng mL-1) and a low limit of detection (0.26 fg mL-1).
- Results obtained from human serum samples showed good agreement with the enzyme-linked immunosorbent assay (ELISA).
Conclusions:
- The developed ratiometric electrochemical immunosensor offers high sensitivity and a broad detection range for IgG.
- The use of CMC-Au-Pb2+ and C-Au-Cu2+ nanocomposites provides a robust platform for electrochemical detection.
- This immunoassay shows significant potential for accurate and sensitive clinical diagnosis.
Abstract:
In this work, we presented a ratiometric electrochemical immunosensor based on redox substrate and immunoprobe. Carboxymethyl cellulose-Au-Pb2+ (CMC-Au-Pb2+) and carbon-Au-Cu2+ (C-Au-Cu2+) nanocomposites were firstly synthesized and implemented as redox substrate and immunoprobe with strong current signals at -0.45 V and 0.15 V, respectively. Human immunoglobulin G (IgG) was used as a model analyte to examine the analytical performance of the proposed method. The current signals of CMC-Au-Pb2+ (Isubstrate) and C-Au-Cu2+ (Iprobe) were monitored. The effect of redox substrate and immunoprobe behaved as a better linear relationship between Iprobe/Isubstrate and Lg CIgG (ng mL-1). By measuring the signal ratio Iprobe/Isubstrate, the sandwich immunosensor for IgG exhibited a wide linear range from 1 fg mL-1 to 100 ng mL-1, which was two orders of magnitude higher than other previous works. The limit of detection reached 0.26 fg mL-1. Furthermore, for human serum samples, the results from this method were consistent with those of the enzyme linked immunosorbent assay (ELISA), demonstrating that the proposed immunoassay was of great potential in clinical diagnosis.
