Electrochemical Immunosensor Using Hydroxyl-Rich Reduced Graphene Oxide

Ultrasensitive Electrochemical Immunoassay Based on HRGO and Functional Polymer-Modified Electrodes

This technology is an electrochemical immunosensor that performs sandwich ELISA-based immunoassays by forming hydroxyl-rich reduced graphene oxide (HRGO) on an electrode surface and attaching a Poly(TMSMA-r-PEGMA-r-NAS) polymer for antibody immobilization. The hydroxyl groups of the HRGO bond with the silane groups of the polymer, which then covalently immobilizes the primary antibody.

Immunosensors have been used to selectively measure trace substances by converting changes from antigen-antibody complex formation into electrical signals. However, conventional graphene or graphene oxide-based immunosensors have struggled to significantly lower detection limits due to insufficient electrochemical catalytic activity.

By combining the high electrochemical catalytic activity of HRGO with stable antibody immobilization via polymers, this technology lowers the target antigen detection limit to 100 ag/mL while ensuring specific selectivity. Applicable to in vitro diagnostics, precision disease biomarker testing, and protein quantification for drug development, it can detect trace antigens that optical ELISA methods often miss.

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Key Features:

• Electrochemical immunosensor with hydroxyl-rich reduced graphene oxide formed on the electrode surface and coated with Poly(TMSMA-r-PEGMA-r-NAS) polymer
• Synthesizing hydroxyl-rich reduced graphene oxide by introducing hydroxyl groups to graphene oxide with a persulfate oxidizing agent, followed by reduction
• Sandwich ELISA immunoassay process involving sequential primary antibody immobilization, target antigen binding, and HRP-labeled secondary antibody binding
• Detecting target antigens at a 100 ag/mL limit by measuring benzoquinone generated from enzymatic reactions in hydrogen peroxide and hydroquinone electrolytes via cyclic voltammetry

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