Label free electrochemical detection of cardiac biomarker troponin T using ZnSnO₃ perovskite nanomaterials

This paper reports label free sub-femtomolar detection of cardiac biomarker troponin T using ZnSnO₃ perovskite nanomaterial based electrochemical biosensors. Herein, we have demonstrated two separate synthesis schemes for the perovskite material, one being a hydrothermal synthesis method, and the other being electrochemical deposition. In this work, for the electrochemical detection of troponin T with the hydrothermally synthesized ZnSnO₃, we have used a glassy carbon electrode (GCE), on to which the nanomaterials are dropcasted so as to create a heterogeneous working electrode. In a separate scheme, we have used indium tin oxide coated polyethylene terephthalate (ITO/PET) substrates as the working electrodes, on to which a thin film of ZnSnO₃ nanomaterial has been deposited electrochemically. Subsequently, the capture antibodies corresponding to the targeted cardiac troponin T are immobilized on to the surface functionalized working electrodes using NHS/EDC chemistry. The electrochemical detection of the target analyte has been performed in the concentration range of 1 fg mL⁻¹ to 1 μg mL⁻¹, using electrochemical impedance spectroscopy. For the GCE and ITO/PET based bioelectrodes, the approximated limits of detection are found to be 0.187 fg mL⁻¹ and 0.571 fg mL⁻¹ respectively, whereas the respective values of sensitivity of the same are 35.25 kΩ (μg mL⁻¹)⁻¹ cm⁻² and 8.813 kΩ (μg mL⁻¹)⁻¹ cm⁻².