Handheld micro blood potassium detection device based on paper-based ion-selective electrodes

Potassium ions (K + ) are essential electrolytes in the human body, crucial for maintaining cell membrane potential, neuromuscular excitability, and cardiac function, with blood potassium (BP) levels needing to stay within 3.5–5.5 mmol/L to prevent serious health issues. Current BP detection methods rely on lab testing, which is costly, slow, and unsuitable for remote areas. This study developed a handheld micro-volume BP detection device using paper-based ion-selective electrodes (ISEs). The device, built on a PET substrate with screen printing and a custom ion-sensitive membrane, features a miniaturized sensor that requires only 2 µL of fingerstick blood for rapid BP measurement, reducing costs significantly. A handheld reader with built-in electrochemical signal processing and wireless transmission allows instant results display and data upload to smartphones. The device demonstrated excellent linearity, repeatability, and stability, indicating its potential for acute care, chronic disease management, and sports medicine.