A dual quartz crystal microbalance for human cardiac troponin T in real time detection

An immunosensor based on dual quartz crystal microbalance (Dual-QCM) for human cardiac troponin T (cTnT) was developed. The self-assembled monolayer by cysteamine was used to immobilize the monoclonal antibody against cTnT (mAb-cTnT). The mAb-cTnT was immobilized on the amine-coated surface via glutaraldehyde. The effect of the cysteamine concentrations on the SAM coated gold sensor was studied as a function of the amount of the immobilized cTnT monoclonal antibodies. A good correlation was found between the cTnT concentration and frequency shift (r = 0.9983). The sensor surface was regenerated by using a solution of 1% (w/v) sodium dodecyl sulphate without losing the immunoreactivity. In this work, it was possible to measure the cTnT without dilution of the human serum with good specificity and reproducibility. The limit of detection was 0.008 ng/mL in this Dual-QCM system. Application of the Dual-QCM immunosensor for clinical samples demonstrated that the results were in good agreement with Electrochemiluminescence Immunoassay (ECLIA).