A Label-Free Potentiometric Sensor Principle for the Detection of Antibody–Antigen Interactions

Abstract

ABSTRACT:We report here on a new potentiometric biosensing principle for the detection of antibody−antigen interactions at the sensing membrane surface without the need to add a label or a reporter ion to the sample solution. This is accomplished by establishing a steady-state outward flux of a marker ion from the membrane into the contacting solution. The immunobinding event at the sensing surface retards the marker ion, which results in its accumulation at the membrane surface and hence in a potential response. The ion-selective membranes were surface-modified with an antibody against respiratory syncytial virus using click chemistry between biotin molecules functionalized with a triple bond and an azide group on the modified poly (vinyl chloride) group of the membrane. The bioassay sensor was then built up with streptavidin and subsequent biotinylated antibody. A quaternary ammonium ion served as the marker ion. The observed potential was found to be modulated by the presence of respiratory syncytial virus bound on the membrane surface. The sensing architecture was confirmed with quartz crystal microbalance studies, and stir effects confirmed the kinetic nature of the marker release from the membrane. The sensitivity of the model sensor was compared to that of a commercially available point-of-care test, with promising results.O

Chemical Modification of Polymer Ion‐Selective Membrane Electrode Surfaces

“…Click chemistry was also used in the fabrication of a virus biosensor 41. Biotin was ‘clicked’ on the N 3 PVC membrane surface, and sensor was subsequently treated with streptavidin and a biotinylated virus antibody, thus creating a sandwich structure on the sensor surface.…”

“…Carboxylated PVC was also used to covalently bind biotin in an avidin sensor 53 based on the surface blocking principle described above 41. Calcium and sodium selective membranes were modified by a reaction with aminated biotin in presence of EDC.…”

Pulsed Galvanostatic Control of a Polymeric Membrane Ion-Selective Electrode for Potentiometric Immunoassays

“…During the preparation of this paper, Bakker et al reported a label-free potentiometric biosensing method for the detection of antibody−antigen interactions at the polymeric membrane surface using zero-current ion fluxes across polymeric membrane ISE. 43 In comparison with the method, the pulsed galvanostatic approach can control marker ions more precisely. In addition, the marker ions are specific to the labeled enzyme, which can reduce the effect of nonspecific interactions at the polymer surface.…”

Pulsed galvanostatic control of a solid-contact ion-selective electrode for potentiometric biosensing of microcystin-LR

“…In recent years, potentiometry based on ion-selective electrodes (ISEs) have evolved to provide a promising transducer for biosensing [22][23][24][25][26]. Typically, these electrodes have been extensively investigated for biosensing via zero-current potentiometry.…”