Rope-skipping for blood plasma separation in point-of-care testing

Plasma separation plays an indispensable role in clinical diagnosis and therapeutic applications, since plasma contains critical biomarkers including proteins and nucleic acids, while interference from the color of red blood cells may compromise the accuracy of biomedical detection. Conventional methods, such as centrifugation, are effective but require specialized equipment, skilled personnel, and significant time, making them impractical for point-of-care testing (POCT) in resource-limited settings. The advent of microfluidic plasma separation techniques has successfully addressed the inherent drawbacks of conventional centrifugation approaches. Herein, we propose a rope-skipping microfluidic centrifugation (RSMC) plasma separation method, aiming to better accommodate POCT scenarios. Specifically, a blood-loaded tube was first secured to the skipping-rope device, and the RSMC device was then rotated manually at about 200 rpm speed. Driven by centrifugal force, efficient plasma separation was achieved without the need for electricity or sophisticated instrumentation. Experimental results demonstrated 67.3% plasma yield with 99.99% purity within 5 min, exceeding the performance of existing manual alternatives like fidget-spinner centrifuges. And the plasma separation system can also achieve pre-processing of large volumes of whole blood samples (∼mL). Moreover, the blood glucose recovery rate of plasma reached as high as 98.3% with this method, which was nearly comparable to that obtained using a standard centrifuge. The RSMC method is characterized by its simplicity, high cost-effectiveness, and ease of operation, making it particularly suitable for POCT applications in resource-limited settings.