Abstract
A novel electrolysis-based micropump using air bubble to achieve indirect actuation is proposed and successfully demonstrated. Unlike most other electrochemical micropumps, our micropump could drive microfluid without the pH-value variation and the choking/sticking phenomena of electrolytic bubbles in the main channel. Besides, the room temperature operation and the low driving voltage used for the electrolysis actuation minimize the possibility of cell-damage. It is promising for biomedical applications, especially for the blood transportation. The whole blood is an intrinsically complex material and difficult to be manipulated in the microdevices. Moreover, the on-chip electrolysis-bubble actuator with the features of large actuation force, low voltage and low power consumption enable portable and implantable lab-on-a-chip microsystems. Utilizing the hydrophobic trapeziform pattern located at the junction of the T-shaped microchannel, the micropump drives the pumped fluid in the main channel and isolates it from the electrolytic bubbles. Our proposed micropump can be used for a variety of applications without constraints on the pumped liquid. Polyethylene glycol (PEG) is employed to modify the surface of PDMS microchannel to prevent the platelet adhesion during pumping operation. According to the platelet adhesion test, there is no clotting during blood pumping operation. The pH-value variation and distribution in the side channel and the main channel is also characterized during electrolysis-actuation operation. Experimental results show that the liquid displacement and the pumping rate could be easily and accurately controlled via the signal of two-phase peristaltic sequence and the periodic generation of electrolytic bubbles. With the applied voltage of 2.5 volts, the maximum pumping rate of 121 nl/min and 88 nl/min were achieved for the DI water and the whole blood, respectively, with the microchannel cross section of 100×50 μm. In this thesis, the design, microfabrication process, characterization and the experimental demonstration of this novel micropump are reported.