基于无透镜全息显微技术的微流控芯片细胞计数方法研究

A microfluidic chip cell counting method based on lens-less holographic microtechnique

目的解决细胞计数领域即时检测发展需求与传统显微镜和流式细胞仪不便于携带的矛盾。方法结合同轴无透镜全息显微与微流控技术,设计一种只有芯片大小的细胞计数装置。该装置利用S型微通道和脉冲进样方式,解决了全息拍摄中曝光时间与样品高速流动的矛盾。利用角谱理论得到衍射传递函数,根据图像传感器采集的原始全息图像重建物面清晰的显微图像。使用阈值分割算法得到细胞的数量和大小信息。结果用直径为7μm和15μm微球代替细胞进行实验验证,本方法的分类及计数结果相对误差不超过5.7%。每帧图像的处理时间为5 s,可以检测大约500个细胞。结论本系统能够为直径7μm以上的细胞进行计数检测,为即时细胞检测提供了一种新的解决方法。

Purposes—To solve the contradiction between the development demand of point-of-care testing in the field of cell counting and the inconvenient portability of traditional microscope and flow cytometry.Methods—Combined with in-line lens-less holographic microscopy and microfluidic techniques,a cell counting device whose volume is as large as an image sensor chip is designed.The device solves the contradiction between the exposure time and high sample flow in holographic shooting by using an S-shaped microchannel.The diffraction transfer function is obtained by using angular spectral theory and micro-images are clearly reconstructed according to the original image that is hologram acquired from an image sensor.The clear micro-images with the above-mentioned processing can obtain the number and size information of cells by using a threshold segmentation algorithm.Results—Experimental verification is made by replacing cells with diameters of 7μm and 15μm microbeads,the relative error of cell classification and counts of two sizes does not exceed 5.7%.The image processing time of each frame is 5 seconds and approximately 500 cells can be detected.Conclusion—This system as a miniature point-of-care detection system is capable of counting detection for cells over 7μm in diameter,thus providing a new solution for cell point-of-care testing.