Development of a disposable potentiometric antibody immobilized ZnO nanotubes based sensor for the detection of C-reactive protein

In this paper, the fabrication of ZnO nanotubes was carried out through chemical etching of ZnO nanorods on the gold coated glass substrates. The monoclonal anti-C-reactive protein clone CRP-8 (mouse lgG1 isotype) with glutaraldehyde was immobilized on these ZnO nanotubes using simple physical adsorption method. The novelty of the present ZnO nanotubes based research is the generation of electromotive force (EMF) in the environment of rapid formation of complex between immobilized antibodies with CRP on the surface of ZnO nanotubes. The electrochemical response of the proposed C-reactive protein (CRP) of human plasma biosensor was measured using potentiometric technique. The antibody immobilized ZnO nanotubes based sensor electrode detected the concentration range of CRP from 1.0 × 10−5 mg/L to 1.0 × 100 mg/L with an acceptable sensitivity of 13.17 ± 0.42 mV/decade. This unusual behavior of the proposed ZnO nanotubes based sensor in no particular electrolytic atmosphere is opening a new way for the detection of proteins at the nanolevel. The response of CRP sensor was highly linear and stable for above detected concentrations. The time response of antibody immobilized ZnO nanotubes based sensor was observed less than 10 s with good selectivity, reproducibility, repeatability and stability. The life time of sensor was not more than three days after use, so it can be used as disposable sensor.