Research Of The Novel And High Throughput Resistive Pulse Sensor For Microparticle Counting On A Microfluidic Chip

Particle rapidly detecting is widely used on ship’s pollution prevention and marine engine monitoring. But the traditional particle detecting equipment is insufficient and shows bad working performance in on-site detecting. The resistive pulse sensor is one of the best choices to solve the problem and can meet the requirements.This thesis reports the research of Coulter resistive pulse sensor on a microfluidic chip, focusing on detecting Signal to Noise ratio and throughput. The main content is divided into three aspects.1)A novel constant current source detecting system was setup. Theoretical analysis of the relation between the particle and the micropore size was derived. By introducing the differential detection mechanism, a 5μm particle was detected. In the experiment, the Signal to Noise ratio of constant current source is significantly higher than the normal constant voltage source.2) A new resistive pulse sensor based on flow focusing method was employed to improve the detecting Signal to Noise ratio. Numerical analysis of flow field was made. The calculation model was demonstrated. In the experiment, the flow field is visualized by 3μm tracer particles. The pure water focusing method shows higher S/N ratio, compared with PBS focusing method.3) A high-throughput differential detecting chip was designed. By adding a common reference channel, the higher Signal to Noise ratio was experimentally got. The 2μm particle was accurately detected. In order to get the throughput of this system, the thesis shows remarkable work in the fitting curve between externally applied hydraulic pressure and the total throughput. The research presents a high throughput and high precision particle detecting system.This thesis provides a new means for particle counting by resistive pulse sensor on microfluidic chips, thoroughly. It is meaningful for developing portable automatic detecting equipment.