Development of a Soft-Landing Type Multi Cell Sorting System

细胞分选机是通过偏转含有单个细胞的滴头来对细胞进行电分选的系统。均匀尺寸的液滴可以由具有压电换能器的喷嘴产生。在喷嘴出口处使用激光束分析细胞，含有细胞的液滴在电场作用下带电并偏转。为了分选原生质体等脆弱细胞，构建了一种使用向上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，将含有细胞的液滴以7至10 m/s的速度向上喷射，并使用静电力通过湿板电极以约0.2至0.4 m/s的降低的入射速度收集。当压电换能器的频率在v = 7 m/s时fp = 4至10 kHz，并且在v = 10 m/s时fp = 6至18 kHz时，可以形成均匀尺寸的液滴。监测偏转的带电液滴的速度和位置，以通过调节液体的流速和充电脉冲与压电换能器脉冲的相位差来稳定液滴轨迹。以胡萝卜原生质体为试验材料。使用传统类型的利用向下喷嘴的细胞分选器，约90%的原生质体在v = 10 m/s时被破坏，约75%在v = 7 m/s时被破坏。在使用向上喷嘴的新型细胞分选器中，该破坏率在v = 10 m/s时可以降低到60 - 75%，在v = 7 m/s时可以降低到25%。在v = 7 m/s的条件下，以10 kHz的液滴形成速率分选原生质体。

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.