Functionalized Graphene Quantum Dots (GQDs) based Label-Free Optical Fluorescence Sensor for CD59 Antigen Detection...

Area of Science:

• Biomaterials Science
• Nanotechnology
• Immunology

Background:

• Cluster of differentiation (CD59) is a cell surface glycoprotein regulating the complement system.
• Altered CD59 expression in cancer aids tumor immune evasion, growth, and immunotherapy resistance.
• Targeting CD59 offers potential for enhancing anti-cancer immune responses.

Purpose of the Study:

• To synthesize and characterize Polyethyleneimine (PEI) functionalized graphene quantum dots (Lf-GQDs) from natural sources.
• To develop a novel immunosensor for the quantitative detection of CD59 antigen.
• To investigate the impact of oriented antibody conjugation on immunosensor sensitivity and selectivity.

Main Methods:

• One-step synthesis of Lf-GQDs from weathered lemon leaf extract.
• Fabrication of an immunosensor using oriented conjugation of Anti-CD59 antibodies onto Lf-GQDs.
• Quantitative detection of CD59 antigen and bioimaging studies of Lf-GQDs cellular uptake in A549 cells.

Main Results:

• Successfully synthesized and characterized Lf-GQDs.
• The Anti-CD59@Lf-GQDs immunosensor demonstrated sensitive CD59 detection in the range of 0.01 to 40.0 ng mL⁻¹.
• Achieved a low limit of detection of 5.3 pg mL⁻¹ for CD59, with enhanced sensitivity and selectivity due to oriented conjugation.

Conclusions:

• The developed Lf-GQDs-based immunosensor provides a highly sensitive and selective platform for CD59 detection.
• Oriented antibody conjugation significantly improves immunosensor performance compared to random conjugation.
• This approach offers a promising pathway for developing nanomaterial-based immunosensors for various cancer biomarkers.