Label free detection of the breast cancer biomarker CA15.3 using ZnO nanorods coated quartz crystal microbalance

The sensing properties of ZnO nanorods which were immobilized with CA15.3 antibody (anti-CA15.3) for CA15.3 detection were studied by using quartz crystal microbalance (QCM) sensors in this work. ZnO nanorods were synthesized at 90 °C by wet chemical route which was used to grow the ZnO nanorods directly on the QCM. The sensors were constructed by binding anti-CA15.3 on ZnO nanorods surface using 3-aminopropyltrietoxy silane (APTES) and glutaraldehyde and were used for CA15.3 detection. The morphology of ZnO nanorods was examined by scanning electron microscopy (SEM). The SEM results indicated the grown ZnO nanorods were well-aligned and the diameter was around 100 nm. These QCM sensors showed high sensitivity (25.34 ± 0.67 Hz/scale (1 U/mL)) and good linearity (0.99) in the concentration range of CA15.3 from 0.5 to 26 U/mL by the experiment. The response time of these sensors were observed less than 10 s with good reproducibility and stability. All the results indicated that one-dimensional ZnO nanostructure is a good material for biosensor application.