A novel electrochemical biosensor based on carboxyethanephosphonic acid coated magnetic Fe3O4 nanoparticles for sensitive detection of resistin

Obesity has emerged as a huge public health issue around the world. Obesity raises the risk of certain chronic diseases, and the assessment of biomarkers indicative of the fundamental biological pathways associated with heightened disease risk may serve as an alternate method to delineate the pertinent obesity phenotype. In this context, we reported a potentially low-cost magneto-electrochemical biosensor built with carboxyl-functionalized magnetic nanoparticles (Fe<inf>3</inf>O<inf>4</inf>@SiO<inf>2</inf>@Cepa MNs)-attached indium tin oxide (ITO) electrode for the measurement of the resistin biomarker. A layer of anti-resistin antibodies was immobilized onto the active carboxyl ends of Fe<inf>3</inf>O<inf>4</inf>@SiO<inf>2</inf>@Cepa MNs via amide bonds, and the Fe<inf>3</inf>O<inf>4</inf>@@SiO<inf>2</inf>Cepa@anti-resistin MNs could detect the resistin obesity biomarker using electrical impedance spectroscopy (EIS). All the modification processes of the MNs were carried out in microcentrifuge tubes, and these MNs were magnetically captured onto the ITO surface for electrochemical measurements. Because of the specific interaction between the anti-resistin antibody and the resistin antigen, this system was highly sensitive and selective for resistin. A linear impedimetric response from 5 pg/mL to 750 pg/mL with a detection limit (LOD) of 1.48 pg/mL for resistin was achieved. The magneto-electrochemical biosensor displayed acceptable accuracy, good reproducibility, and high selectivity. Moreover, the high stability of the functionalized magnetic nanoparticles allowed the designed biosensing platform to obtain long-term stability. This magneto-electrochemical biosensor was successfully applied to the analysis of resistin in real samples, and the results of real samples detected by this system were in acceptable agreement with those measured by enzyme-linked immunosorbent assay (ELISA). Furthermore, high recovery rates in actual sample detection displayed that this magneto-electrochemical biosensor was a promising tool to be applied to the detection of resistin in clinical diagnosis. © 2024