A Novel Self-Activated Mechanism for Stable Liquid Transportation Capable of Continuous-Flow and Real-time Microfluidic PCRs

Abstract

The self-activated micropump capable of velocity-stable transport for both single-phased plug and double-phased droplet through long flow distance inside 3D microchannel is one dream of microfluidic scientists. While several types of passive micropumps have been developed based on different actuation mechanisms, until today, it is still one bottleneck to realize such a satisfied self-activated micropump for the stable delivery of both single and double-phased liquid inside long microchannel (e.g., several meters), due to the lack of innovative mechanism in previous methods. To solve this problem, in this article, we propose a new self-activated pumping mechanism. Herein, an end-opened gas-impermeable quartz capillary is utilized for passive transport. Mechanism of this micropump is systemically studied by both the mathematical modeling and the experimental verifications. Based on the flow assays, it totally confirmed a different pumping principle in this paper, as compared with our previous works. The R 2 value of the overall flow rates inside the 3D microchannel is confirmed as high as 0.999, which is much more homogeneous than other passive pumping formats. Finally, this novel micropump is applied to continuous-flow real-time PCRs (both plug-type and microdroplet-type), with the amplification efficiency reaching 91.5% of the commercial PCR cycler instrument.

Advances in Simple, Rapid, and Contamination-Free Instantaneous Nucleic Acid Devices for Pathogen Detection

“…This innovative design eliminates the need for expensive external pumps by implementing an automated sample injection directly into the reaction chamber, enabling in situ pathogen detection in the field. Another noteworthy advancement by Wu et al involved the development of a self-activating pumping mechanism [123]. They utilized end-open impermeable quartz capillaries for passive delivery.…”

A New Self-Activated Micropumping Mechanism Capable of Continuous-Flow and Real-Time PCR Amplification Inside 3D Spiral Microreactor

“…Recently, the authors have introduced a novel pumping principle and method for application in both the passive and stable velocity transport of a liquid [19,20]. This was achieved by applying an end-open gas-impermeable quartz tube to automate the flow for the first time.…”

“…The purpose of using stretched tube instead of quartz tube is to solve the problem that the fluid velocity changes greatly after the liquid enters the smaller diameter quartz tube (ID = 25 µm). Previous experiments showed that when liquid with different viscosities flows to the entrance of the quartz tube, the flow rate changes greatly [19,20]. The reason for this phenomenon is that the inner diameter of the interface between quartz tube and Teflon tube has changed dramatically, due to a sudden great change of the resistance at the junction.…”