Sensors and Actuators B: Chemical, vol.433, 2025 (SCI-Expanded)
An innovative magnetosensing strategy for highly sensitive impedimetric determination of anti-tissue transglutaminase antibodies (anti-tTG) was developed and applied successfully in real serum and saliva samples. The transducer surface of the proposed immunosensor consisted of an indium tin electrode (ITO) attached with poly(3-thienylacetic acid) (PTAc)-coated magnetic nanoparticles, which provided a very useful surface for the attachment of the biological molecules. The PTAc-coated magnetic nanoparticles were held by a magnetic field on the electrode surface, and the immunological reaction was carried out on magnetic nanoparticles as a solid platform on which the tissue transglutaminase (tTG) was covalently bound. With the specific capture of anti-tTG on the tTG-immobilized surface, an impedimetric signal was measured, and the electrochemical response of this specific reaction was correlated with the anti-tTG concentration. A linear relationship between the impedimetric signal and the anti-tTG concentration was obtained over a wide range of 0.125–25 U/mL. This magneto-biosensor illustrated a stable quantitative signal to anti-tTG concentrations after 45 minutes of incubation with a limit of detection of 0.034 U/mL and a low relative standard deviation (RSD) of 3.61 %, n = 3. This immunosensor's electrochemical behaviour was thoroughly examined, with consideration given to factors including sensitivity, specificity, repeatability, reproducibility, and storage stability. Lastly, serum and saliva samples were analyzed using the biosensor, and excellent correlation was achieved between the commercial ELISA kit and the proposed immunosensor. As a result, this approach held out a lot of hope for a straightforward, affordable, and user-friendly analytical technique that would enable the label-free measurement of anti-tTG levels.