为了喷射细胞并保持高的细胞活性,设计并搭建了一套基于气动阀控技术的微液滴按需喷射装置.该装置主要部件包括储液腔体、位于腔体底部的100μm直径喷嘴、以高速电磁阀和放气管为核心的气路以及液滴拍照系统.该装置利用高速电磁阀产生气体压强脉冲,迫使储液腔内液体挤出喷嘴,形成液滴;气体随后经放气管排出,恢复储液腔内气压平衡.经拍照系统验证,该装置实现了稳定的单液滴喷射,喷射频率可以达到20 Hz,液滴直径约200μm,实现了对人外周血淋巴细胞和培养基的喷射.流式细胞检测显示,细胞经喷射过程的存活率接近100%.%To print cells and maintain high cell viability, a pneumatic droplet-on-demand ( DOD) system was designed. The key components of the system included a chamber for liquid sample, a tiny orifice of 100μm. The chamber was connected to a Nitrogen gas tank with a high speed solenoid valve, and to the ambiance with a venting tube. A photographic system was used to evaluate the uniformity and consistency of the DOD system. A pressure pulse was created within the chamber via controlling the solenoid valve. The liquid was pushed out through the nozzle, generating a droplet. The gas was then released through the venting tube, recovering the system back to equilibrium. As confirmed by the photographic system, stable generation of single droplet was realized, with a generation frequency of 20 Hz, and with droplet diameter around 200μm. Finally, jetting of human peripheral blood lymphocytes ( PBL) and buffer was tested. Based on flow cytometry studies, the impacts of the micro-drop generation process on viability of the human PBLs were found to be negligible.
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