An electrochemical biosensor for the determination of folic acid in pregnant women based on DHFR/c-MWCNTs/TiO2NPs modified gold electrode

The present research article describes a newly designed sensing method for determining folic acid levels. Folic acid is a B vitamin that helps the body makes healthy new cells. It is also known as vitamin B9 or folic acid. A new folic acid biosensor was constructed based on dihydrofolic acid reductase (DHFR) immobilized on c-MWCNT/TiO2NPs modified gold electrode. Prepared titanium dioxide nanoparticles have been characterized by Transmission electron microscope (TEM), X-Ray Diffractometer (XRD), and Fourier Transform Infrared spectroscopy (FTIR). Fabricated working gold electrode (i.e. DHFR/c-MWCNTs/TiO2NPs/AuE) was characterized at various stages of its construction by Scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), FTIR, and cyclic voltammetry to confirm its fabrication. The biosensor showed an optimum response at pH 7.5 and 35 ​°C temperature. The maximum current of the constructed folic acid biosensor was due to electrons generated at 0.125 ​V against Ag/AgCl electrode. The proposed biosensor showed a low detection limit (11.48 ​nM), a wide linear range (5 ​nM–50 ​nM), a sensitivity of 0.42 ​μA/nM/cm2, and good storage stability. Folic acid biosensor was evaluated and utilized for folic acid level quantification in serum samples of pregnant women.