Sandwich-Type Electrochemiluminescence Immunosensor Based on CDs@dSiO₂ Nanoparticles as Nanoprobe and Co-Reactant

Area of Science:

• Electrochemiluminescence (ECL) biosensing
• Nanomaterial-based diagnostics
• Green chemistry in analytical methods

Background:

• Efficient electrochemiluminescence (ECL) systems typically rely on co-reactants.
• Conventional co-reactants often pose toxicity concerns, necessitating environmentally friendly alternatives.
• Developing sustainable co-reactants is crucial for advancing ECL technology.

Purpose of the Study:

• To synthesize and characterize carbon dots (CDs) integrated with dendritic silica nanospheres (CDs@dSiO2 NPs) as a novel, eco-friendly co-reactant.
• To construct a highly sensitive and selective sandwich electrochemiluminescence (ECL) immunosensor for human chorionic gonadotropin (HCG) detection.
• To evaluate the performance of the developed immunosensor, including its limit of detection, stability, and selectivity.

Main Methods:

• Synthesis of carbon dots (CDs) and their assembly with dendritic silica nanospheres (dSiO2 NPs).
• Construction of a sandwich immunosensor utilizing CDs@dSiO2 NPs as co-reactants and Ru(bpy)32+ as a luminophore.
• Electrochemical and ECL measurements for HCG detection and sensor performance evaluation.

Main Results:

• The synthesized CDs@dSiO2 NPs demonstrated excellent performance as co-reactants for Ru(bpy)32+ in ECL systems.
• The developed ECL immunosensor achieved a remarkably low limit of detection (LOD) of 0.00019 mIU/mL for HCG.
• The immunosensor exhibited superior stability and selectivity, outperforming traditional methods.

Conclusions:

• Carbon dots (CDs) integrated with dendritic silica nanospheres offer a low-toxic, efficient, and environmentally friendly alternative co-reactant for ECL applications.
• The developed ECL immunosensor shows significant potential for sensitive and reliable clinical detection of HCG.
• This work paves the way for greener and more effective biosensing platforms in diagnostics.