MWCNT-Au-Pt hybrid nanocomposite-based electrochemical immunosensor for FGF-2 detection: a novel strategy for anxiety disorder diagnosis.

The accurate diagnosis of anxiety disorders remains challenging, as current detection methods primarily rely on subjective questionnaires. In this study, a novel electrochemical biosensor for the detection of fibroblast growth factor-2 (FGF-2), a biomarker associated with anxiety disorders, was developed for the first time. The sensing principle was based on monitoring the impedimetric signal changes generated by the interaction between anti-FGF-2 and the FGF-2 antigen, using a carbon screen-printed electrode as the transducer. To enhance the sensitivity and overall performance of the biosensor, a multi-walled carbon nanotube-gold-platinum (MWCNT-Au-Pt) hybrid nanocomposite was incorporated into the immunosensor structure. Critical parameters-including the amount of MWCNT-Au-Pt, the concentration, incubation time, and temperature of anti-FGF-2, as well as the incubation time and temperature for the anti-FGF-2/FGF-2 interaction-were systematically optimized. Under optimized conditions, the developed impedimetric FGF-2 immunosensor exhibited a linear response in the range of 10-100 ng/mL, with a limit of detection of 1.01 ng/mL and a limit of quantification of 3.10 ng/mL. The specificity of the sensor was confirmed in the presence of potential interfering substances. For real sample analysis, human saliva samples (n = 30) were diluted appropriately and spiked with FGF-2 at concentrations of 20, 50, and 75 ng/mL. The obtained recovery values demonstrated that the developed impedimetric FGF-2 immunosensor is highly suitable for real-sample applications and holds significant potential as a reliable tool for the detection of anxiety disorders.