Basic Research Of Droplets Manipulating And Controlling Technology Based On Digital Microfluidic

There are two types of droplet microfluidic technology, namely channel droplet technology and digital microfluidics (abbreviated as DMF). In DMF, electric fields are applied on electrodes. Theoretically, surface tension of a droplet between the dielectric layer and the liquid on top of it was modified. Also, the movement of individual droplets on dielectric surfaces was controlled to achieve the dispersion, splitting, transportation and merging. Recently, DMF emerged as a mature technology and demonstrated broad application potential, and eventually it will make unique contribution in chemistry, biology and medicine.For the purpose of low-cost and middle-scaled throughput digital microfluidic chips' design and fabrication, we proposed a sample introduction module and optimized the droplet manipulation operation. Furthermore, a precise manipulation of multiple steps was achieved, including droplet automatic importing, fusion, fission and accurate capture of droplets, and post-reaction droplet recollection. On this basis, protein biofouling on the DMF was studied. These improvements are beneficial to further development of digital microfluidics application. The major work in this thesis includes:Firstly, the existing digital microfluidics chip platform was optimized and improved, and the upgrade system was tested and gotten feedback in order to improve the rationality and stability of digital microfluidic chip.Secondly, a sample introduction module was proposed and the droplet manipulation operation was optimized. Furthermore, a precise manipulation of multiple steps was achieved, including droplet automatic importing, fusion, fission and accurate capture of droplets, and post-reaction droplet recollection. A series of fundamental technical difficulties were addressed and the related novel techniques in droplet manipulation were proposed.Lastly, protein biofouling on DMF was inhibited through the use of some surfactants and a new super hydrophobic layer. The effect of different surfactants and the degree of protein biofouling on different plate-based digital microfluidic chip was evaluated objectively. This work will pave a way to minimize protein biofouling and laid a solid foundation for expending the application of digital microfluidics.