Design and fabrication of air-flow based single particle dispensing system

In this paper, we discuss the design and fabrication approach to increase the success rate of single particle dispensing. Two pairs of capacitance sensors are placed in a biochip to detect the flow velocity of particles, and the air pressure is applied to eject particles by synchronizing the timing. Comprehensive design theory, which is taken into account of the back pressure caused by air pressure, the response time of the system, sensor property, and the delay of the dispensing from the air pressure, is developed in order to minimize the disturbance of the system and maximize the throughput of the ejection system. Then, the system has capability to eject 3 particles/sec and maximum flow velocity is 10 mm/s. The novelty of the system is that the biochip is disposable which is unlike the conventional mechanical inkjet system and it can prevent contamination. Therefore, the fabricated disposable biochip based on photolithography is low cost and the drive system is reusable. Finally, we succeed in automatic dispensing of a single particle (=100 µm) from a biochip to culture well atmosphere using developed cell ejection system with the success rate of 50 %.