▎ 摘　　要

Laser-scribed graphene (LSG) electrodes have gained significant interest due to the ease in fabrication, surface modification, and potential to develop various types of electrochemical sensors and biosensors. In these studies, a new type of zinc ferrite nanoparticles (ZnFe2O4 NPs) modified LSG electrochemical sensing system comprising LSG-ZnFe2O4 working electrode, LSG reference, and LSG counter electrode on a single polyimide substrate is presented. LSG-ZnFe2O4 electrodes are fabricated by drop-casting a solution of ZnFe2O4 NPs onto the LSG electrode, which gave a 31% enhancement of sensitivity and electrocatalytic activity compared to the bare LSG electrode. LSG-ZnFe2O4 electrochemical aptasensor for acute myocardial infarction (AMI) screening is developed by detecting the cardiac Troponin-I (cTn-I) biomarker. The results show that the developed aptasensor could detect a broad concentration range of cTn-I with a limit of detection of 0.001 ng/mL and a sensitivity of 19.32 (+/- 0.25) mu A/(ng/mL). In addition to this, LSG-ZnFe2O4-aptasensor shows higher selectivity towards the detection of cTn-I and negligible cross-reactivity with other interfering biomolecules. Finally, it is demonstrated that LSG-ZnFe2O4-aptasensor can easily detect different concentrations of cTn-I spiked in human serum samples. These results show that the LSG-ZnFe2O4-aptasensor is a promising diagnostic tool to monitor cTn-I and could be a potential candidate to develop point-of-care devices for cTn-I biomarker detection and various other disease biomarkers in the future. (C) 2021 Elsevier Ltd. All rights reserved.