Nanomagnet Bioconjugates with anti‐CRP Polyclonal Antibodies as Nanobioprobes for Enhanced Impedimetric Detection of CRP

Abstract

Selective purification of biological materials for their detection in complex sample matrix is a general challenge for many researchers working in the field of diagnostics. Magnetic nanoparticles functionalized with biological molecules that impart biomolecular selectivity are therefore of major interest as capture probes thus allowing for magnetic separations. Nanoparticles can also be used for the enhanced detection of biomarkers. In this work, an ultrasensitive sandwich-based impedimetric immunosensor was fabricated for the detection of Creactive protein antigen (CRPAg). Stable and oriented immobilization of anti-CRP monoclonal antibody was achieved onto electrografted phenylethylamine derivat-ized with succinic anhydride and phenylboronic acid via carbodiimide chemistry. The detection of CRPAg was achieved using Electrochemical Impedance Spectroscopy (EIS). The enhancement of the impedance charge-transfer resistance (R CT ) signal was achieved using the sandwich approach. The anti-CRP polyclonal antibody was immobilized in an oriented manner onto magnetic nanoparticles functionalized with phenylboronic acid. The increase in the change in charge-transfer resistance (ΔR CT ) values was linearly proportional to the concentration of CRPAg in the range 10 to 200 ng mL À 1 covering the clinical range for CRPAg detection and with a detection limit of 0.34 ng mL À 1 .

Hybrid Impedimetric Biosensors for Express Protein Markers Detection

“…This section describes nanomaterials that are somewhat less common but are also successfully used to create impedimetric biosensors. Such materials include colloidal quantum dots [152,153], which during the synthesis process are formed with a shell of ligand molecules, two-dimensional nanomaterials from other semiconductor compounds [154][155][156], and, finally, magnetic nanoparticles [157,158].…”