Research On Digital Microfluidic Systems For Nucleic Acid Detection

Nucleic acid detection(NAT)is an indispensable method of clinical medical research,gene detection and genetic analysis.And polymerase chain reaction(PCR)is the most commonly used technique in NAT.With the simple structures,accurately controlling the droplets in the microfluidic chip through the electrical signal and high compatibility with digital integrated circuit technology,Electrowetting-on-dielectric(EWOD)digital microfluidic chip,has great advantages in the integration and automation.Digital microfluidic PCR system integrated a traditional PCR instrument on the PCR microchip and made PCR realized on a digital microfluidic chip.Combined with the related literature,the principle of digital microfluidic technology and nucleic acid detection technology are-summarized and analyzed in this dissertation.The key of PCR technology is to control the time and temperature of the three reaction stages of PCR precisely.On this basis,a EWOD digital microfluidic PCR system was designed and fabricated.A parallel-plate digital microfluidic chip was designed and fabricated,as well as effects of different dielectric layer materials on the performance of digital microfluidic devices were studied by several experiments.The drive circuits and control programs of microfluidic chip were designed,and the driving effect of digital microfluidic system on droplet actuation was tested.The temperature control system of the digital microfluidic PCR system was designed and built.And the temperature control of the three reaction areas was stable and can meet the requirements of PCR technology,which means the running test performance was excellent.Therefore,the feasibility and correctness of the EWOD digital microfluidic system for NAT were verified.