A compact on-chip microsensor for dual-channel measurement of potassium and creatinine in whole blood

Blood potassium and creatinine levels are critical indicators for managing chronic kidney disease (CKD). In response to the need for home monitoring and emergency care, point-of-care diagnostic technologies based on microsystems have emerged, nevertheless they remain limited in portability and speed for direct in whole blood samples measurement. To enable direct blood detection of potassium and creatinine for effective CKD management, this study presents a novel on-chip self-driven dual-channel optical microsensor designed for real-time monitoring of potassium and creatinine levels in whole blood. Utilizing 3D printing technology to design and fabricate microstructures, and integrating microchannels with a filtration layer, this microsensor requires only 10 μL of blood for single-pass sample filtration and dual-parameter detection. A novel passive blood sample pumping method is proposed, utilizing internal and external pressure differentials along with internal hydrophilic properties to facilitate sample flow into the detection chambers. Light-emitting diodes (LEDs) and photodiodes, positioned on either side of the detection chamber, are employed to measure the concentrations of blood indicators. The detection results can be instantly handheld read and uploaded to the cloud via intelligent terminal, enabling seamless follow-up diagnostics and treatment. Through multiple rounds of testing on animal serum samples, whole blood samples, and real porcine blood samples, this microsensor demonstrated excellent linearity and accuracy. This innovative microsensor, designed for direct testing from a minimal volume of whole blood, holds significant potential for improving CKD management, offering a portable, reliable alternative for preoperative diagnostics and home-based chronic disease monitoring.