Electrochemical paper-based analytical device for multiplexed, point-of-care detection of cardiovascular disease biomarkers

Cardiovascular diseases (CVDs) are the number one cause of death globally. Therefore, a sensitive and affordable point-of-care sensing device is needed for the diagnosis and monitoring of diseases. Herein, we demonstrated an electrochemical paper-based analytical device (ePAD) coupled with a label-free immunoassay for simultaneous determination of three important CVDs biomarkers including C-reactive protein (CRP), troponin I (cTnI), and procalcitonin (PCT). The ePAD was created by stacking a wax-patterned paper and a transparency film using laser-cut double-sided adhesive to define the sample inlet, three separate detection zones for each analyte, and fluidic channels that connect the inlet and detection zones. Antibodies to the target biomarkers were immobilized on graphene oxide (GO)-modified carbon electrodes stencil-printed on the ePAD. Concentrations of the CVDs biomarkers were determined by square wave voltammetry (SWV). A significant decrease in current response in a concentration-dependent manner was observed in the presence of the cardiac biomarkers while there was no observable change in current response in the absence of the biomarkers. Good linearity (R-2 > 0.99), low detection limits (0.38 ng mL(-1), 0.16 pg mL(-1) , and 0.27 pg mL(-1) for CRP, cTnI, and PCT, respectively), and good reproducibility (RSD < 5 %) were achieved for the quantifications. Furthermore, the immunosensor has been applied to simultaneously detect the three biomarkers in serum samples with satisfactory results. The proposed immunosensor can be a great alternative for the early detection of cardiovascular diseases at the point-of-care.