Microsystems Technology Division, Centre of Natural Hazard and Disaster Science (CNDS), Uppsala University, Box 35, 751 03, Uppsala, Sweden.
Sci Rep. 2021 Nov 18;11(1):22504. doi: 10.1038/s41598-021-01865-4.
In microfluidics, a well-known challenge is to obtain reproducible results, often constrained by unstable pressures or flow rates. Today, there are existing stabilisers made for low-pressure microfluidics or high-pressure macrofluidics, often consisting of passive membranes, which cannot stabilise long-term fluctuations. In this work, a novel stabilisation method that is able to handle high pressures in microfluidics is presented. It is based on upstream flow capacitance and thermal control of the fluid's viscosity through a PID controlled restrictor-chip. The stabiliser consists of a high-pressure-resistant microfluidic glass chip with integrated thin films, used for resistive heating. Thereby, the stabiliser has no moving parts. The quality of the stabilisation was evaluated with an ISCO pump, an HPLC pump, and a Harvard pump. The stability was greatly improved for all three pumps, with the ISCO reaching the highest relative precision of 0.035% and the best accuracy of 8.0 ppm. Poor accuracy of a pump was compensated for in the control algorithm, as it otherwise reduced the capacity to stabilise longer times. As the dead volume of the stabiliser was only 16 nL, it can be integrated into micro-total-analysis- or other lab-on-a-chip-systems. By this work, a new approach to improve the control of microfluidic systems has been achieved.
在微流控技术中，一个众所周知的挑战是获得可重复的结果，这通常受到不稳定的压力或流速的限制。如今，已经有针对低压微流控或高压宏观流控的现有稳定器，它们通常由被动膜组成，无法稳定长期波动。在这项工作中，提出了一种新的能够处理微流控中高压的稳定化方法。它基于上游流动电容和通过 PID 控制限流芯片控制流体粘度。该稳定器由具有集成薄膜的耐高压微流控玻璃芯片组成，用于电阻加热。因此，稳定器没有移动部件。通过 ISCO 泵、HPLC 泵和 Harvard 泵对稳定器的稳定性进行了评估。所有三种泵的稳定性都得到了很大的提高，ISCO 达到了最高相对精度 0.035%和最佳精度 8.0 ppm。在控制算法中补偿了泵的精度差，否则会降低长时间稳定的能力。由于稳定器的死体积仅为 16 nL，因此可以集成到微全分析或其他芯片实验室系统中。通过这项工作，实现了一种改进微流控系统控制的新方法。
