A nanoforce ZnO nanowire-array biosensor for the detection and quantification of immunoglobulins

Lysozyme was covalently immobilized onto self-assembled monolayer (SAM) 3-mercaptopropanoic acid, linked to hydrothermally synthesized ZnO nanowires. Immobilization was confirmed by atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy and fluorescence microscopy. Adherence of antibodies to immobilized lysozyme ZnO nanowire constructs showed a strong indication of a piezoelectric signal, observed as an increase in voltage due to the presence of a Schottky barrier. The piezoelectric energy generated increased with an increase in antibody levels. The biosensor was studied by AFM, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The response of the piezoelectric nanoforce biosensor is in a linear relationship with antibody concentration ranges from 50 ng/ml to 1 μg/ml, with a limit of detection (LOD) of 102.76 ng antibodies/ml.