Development of a Soft-Landing Type Multi Cell Sorting System

细胞分选机是通过偏转滴管对单个细胞进行电分选的系统。均匀大小的液滴可以由带有压电传感器的喷嘴产生。在喷嘴出口处使用激光束对电池进行分析，并且包含电池的液滴被电场带电并偏转。为了对原生质体等脆弱细胞进行分选，构建了一种采用上向喷嘴的软着陆型细胞分选机，并对其基本特性进行了研究。使用直径为150微米的喷嘴，将含有电池的液滴以7 ~ 10m /s的速度向上喷射，并通过湿板电极利用静电力以减小的入射速度约0.2 ~ 0.4 m/s收集。当压电换能器的频率为v = 7 m/s时fp = 4 ~ 10 kHz, v = 10 m/s时fp = 6 ~ 18 kHz时，可形成大小均匀的液滴。通过调节液体流速和充电脉冲与压电换能器脉冲的相位差，监测偏转的带电液滴的速度和位置，稳定液滴的运动轨迹。以胡萝卜原生质体为试验材料。使用向下喷嘴的传统类型细胞分选器，在v = 10 m/s时约90%的原生质体被破坏，在v = 7 m/s时约75%的原生质体被破坏。在v = 10m /s时，这种破坏率可以降低到60 - 75%，在v = 7m /s时，这种破坏率可以降低到25%，使用向上喷嘴的新型细胞分选机。在v = 7 m/s条件下，原生质体的形成速率为10 kHz。

Cell sorter is system that sort cells electrically by deflecting dropler which contains single cell. The uniform sized liquid droplets can be generated by a nozzle with a piezoelectric transducer. The cell is analyzed using a laser beam at the outlet of the nozzle, and the droplet containing the cell is charged and deflected by an electric field.In orderf to sort fragile cells such as protoplasts, a soft-landing type cell sorter using an upward nozzle was constructed, and its basic characteristics have been studied. Using a nozzle with 150 micrometer diameter, liquid droplets containing cells are sprayed upward with 7 to 10 m/s velocity, and are collected with reduced incident velocity of about 0.2 to 0.4 m/s by a wet plate electrode using an electrostatic force. Uniform sized liquid droplets can be formed wwhen frequency of the piezoelectric transducer, fp = 4 to 10 kHz at v = 7 m/s, and fp = 6 to 18 kHz at v = 10 m/s. Velocity and position of deflected charged droplets are monitored to stabilize the droplet trajectory by adjusting the flow rate of the liquid and the phase difference of the charging pulse to the piezo- electric transducer pulse. Protoplasts of carrot were used as the test sample. With conventional type cell sorter utilizing a downward nozzle, about 90 % of the protoplasts were destroyed at v = 10 m/s, and about 75 % at v = 7 m/s. This destruction rate can be lowered to 60 to 75 % at v = 10 m/s, and to 25 % at v = 7 m/s in the novel type cell sorter utilizing the upward nozzle. The protoplasts could be sorted with the droplet formation rate of 10 kHz at v = 7 m/s.