ZnO nanoflower-decorated field-effect transistor biosensor for ultrasensitive point-of-care testing of NT-proBNP

A point-of-care testing device was proposed for the ultrasensitive detection of NT-proBNP. • A ZnO nanoflower-decorated field-effect transistor was constructed to amplify the signal response. • The POCT device demonstrated high selectivity for NT-proBNP with detection limit of 3.3 fg/mL. • This work provides a robust platform for early warning of AMI in emergency settings. N-terminal pro-B-type natriuretic peptide (NT-proBNP) is an established circulating biomarker of myocardial wall stress and cardiac dysfunction and is widely used in the clinical assessment of heart failure (HF). Its circulating concentration provides important information for HF diagnosis or exclusion, risk stratification, and prognostic evaluation. Because HF can arise from different cardiovascular conditions, including ischemic myocardial injury after acute myocardial infarction (AMI), rapid and reliable NT-proBNP measurement is also valuable for evaluating cardiac dysfunction and subsequent cardiovascular risk in acute cardiovascular settings. In this work, we developed a point-of-care testing (POCT) device based on a ZnO nanoflower-modified field-effect transistor (FET) for NT-proBNP biosensing. The three-dimensional ZnO nanoflower architecture offers a high specific surface area and abundant active sites for bioreceptor immobilization, while its micro-nano hierarchical structure enhances local electric-field modulation and signal transduction. By integrating a target-induced strand-release strategy, the POCT device exhibits a linear response over the concentration range of 0.01–10000 pg/mL, achieving a detection limit of 3.3 fg/mL and an optimized detection time of 20 min. Furthermore, by incorporating a capillary-driven microfluidic system that enables sequential sample delivery and washing, the proposed POCT device provides reliable NT-proBNP detection in serum samples. This POCT platform provides a portable strategy for rapid NT-proBNP measurement and shows potential for HF assessment, cardiovascular risk stratification, and disease monitoring, including the evaluation of cardiac dysfunction in patients following AMI. Download: Download high-res image (196KB) Download: Download full-size image A POCT device based on ZnO nanoflower-modified FET enables ultrasensitive determination of NT-proBNP within 30 min.