It is desirable for medical diagnostic assays to have portable and low cost pumping schemes. Although capillary loading is the most common example, it cannot load dead-end channels, often have fibres that obstruct optics, and have surface treatment or geometrical constraints. On the other hand, conventional degas pumping lacks flow control, speed, and reliability. Here we report a new portable pumping system that does not require any peripheral equipment or external power sources/controls. Compared with conventional degas pumping, it has ~8 times less standard deviation in speed, is operational for >2 hours, can tune and increase loading speed up to 10 times, and can maintain a slower exponential decay of flow rate (factor of 5 increase in time constant). As an example, we show it was possible to integrate this pumping system with one-step sample prep and digital amplification, and demonstrated quantitative detection of DNA in one-step (10~10^5 copies DNA/μl). We believe this integrated power-free pumping design may become a fundamental building block for future point-of-care diagnostic devices.
Project end date: 08/26/15