High Sensitivity Inkjet-printed Organic Electrochemical Transistors (OECTs) for Applications in Heart Disease Point-of-Care Diagnostics

Abstract

Heart failure, a class of cardiovascular diseases, is one of the leading causes of death worldwide. Early detection of heart disease has a major impact on slowing down disease progression and improving patient outcomes. B-type natriuretic peptide (BNP) and its N-terminal prohormone (NT-proBNP) are HF biomarkers that have high diagnostic and prognostic value. In this work, we developed a point-of-care biosensing platform for the detection of B-type natriuretic peptide (BNP) and its N-terminal prohormone (NT-proBNP) via organic electrochemical transistors (OECTs). The OECTs were built using state-of-the-art inkjet printing technology, a scalable, highly reproducible, and low-cost fabrication process. The inkjet technology can reach a resolution of a few tens of micrometers with reduced material waste, low manufacturing cost, and processing temperatures. The fabricated devices were printed on glass substrates with silver nanoparticles source and drain electrodes. Minimum sheet resistance of (0.03 Ω/sq) was achieved by optimizing silver nanoparticles layer thickness. (3,4- ethylenedioxytiophene):poly(styrenesulfonate) (PEDOT:PSS), a low impedance organic semiconductor, was used as channel material. The PEDOT:PSS channel was optimized for a high cross-sectional area to channel length (Wd/L) ratio at 1857 µm reaching a maximum corresponding transconductance value of 15.2 mS, an order of magnitude improvement on published work. The design was tested with BSA protein and yielded a limit of detection (LoD) of 1 pM with a linear response in the region between 1 pM to 10 µM, well within the clinically relevant concentrations of BNP and NT-proBNP in blood. This study shows the potential of inkjet printing for fabricating low cost, high performance OECT-based point-of-care biosensors.