Point-of-care testing (POCT) is destined to play a much greater role in chronic disease diagnosis and management. Advanced POCT systems are being developed to deliver less costly and more acute healthcare in a patient’s home, but remain scarce. Especially lacking are miniature devices, similar to the commonly used blood glucose meter, to quantitatively detect low concentrations of protein biomarkers in blood. Here, a unique integrated system solution is presented, which represents a significant step beyond proof-of-concept high sensitivity nanosensors, for quantitative reading of b-type natriuretic peptide (BNP) in outpatient blood. BNP is an established biomarker for early heart failure (HF) diagnosis and prognosis. HF is an epidemic affecting more than 26 million people worldwide and a chronic disease with ever increasing prevalence. Currently, accurate and quantitative BNP blood tests are only available in central laboratory and emergency room using venous blood. Highly sensitive carbon nanotube thin film (CNT-TF) impedance sensors are integrated into a user-friendly POCT system, NanoBot, which consists of two parts: a disposable test strip and a miniature electrical readout unit. Using electrochemical impedance spectroscopy (EIS), combined with standard addition, NanoBot is demonstrated to detect blood BNP with a limit of detection (LOD), precision, and accuracy comparable to those of a standard immunofluorescence assay (IFA) and a commercial emergency room POCT device. A pilot clinical study with patient-derived blood plasma validates that NanoBot has not only strong performance, but also other advantages such as low sample volume, label-free and wash-free detection. Collectively, NanoBot’s performance and operational characteristics signify its promising potential as a POCT device for home-use heart failure diagnosis.
1. Various aspects of electrochemical immunosensors for high-sensitivity detection of protein biomarkers
2. Recent advances and challenges in developing nano-biosensors
3. The need for disruptive technology to make the change from centralized healthcare to distributed healthcare