Fabrication of an affordable and sensitive corticosteroid-binding globulin immunosensor based on electrodeposited gold nanoparticles modified glassy carbon electrode.

ABSTRACT

Herein, we fabricated an ultrasensitive electrochemical immunosensor for the quantitative detection of corticosteroid-binding globulin (CBG). CBG is a protein that regulates glucocorticoid levels and is an important biomarker for inflammation. A decrease in CBG levels is a key biomarker for inflammatory diseases, such as septic shock. To enhance the electrochemical performance and provide a large surface area for anti-CBG immobilization, we functionalized the glassy carbon electrode surface with AuNPs. Electrochemical characterization methods including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to examine the construction of the fabricated immunosensor. The electrochemical signal demonstrated a remarkable sensitivity to the CBG antigen, with a detection range from 0.01 to 100 µg/mL and a limit of detection of 0.012 µg/mL, making it suitable for both clinical and research applications. This label-free immunosensor offers significant advantages, including high sensitivity, low detection limits and excellent selectivity, making it a promising tool for detecting CBG in complex biological samples. Its potential applications include early disease diagnosis, treatment monitoring and studying CBG-related physiological processes.