Cheng Xuanhong, Liu Yi-shao, Irimia Daniel, Demirci Utkan, Yang Liju, Zamir Lee, Rodríguez William R, Toner Mehmet, Bashir Rashid
BioMEMS Resource Center and Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
Lab Chip. 2007 Jun;7(6):746-55. doi: 10.1039/b705082h. Epub 2007 May 11.
Cell-based microfluidic devices have attracted interest for a wide range of applications. While optical cell counting and flow cytometry-type devices have been reported extensively, sensitive and efficient non-optical methods to detect and quantify cells attached over large surface areas within microdevices are generally lacking. We describe an electrical method for counting cells based on the measurement of changes in conductivity of the surrounding medium due to ions released from surface-immobilized cells within a microfluidic channel. Immobilized cells are lysed using a low conductivity, hypotonic media and the resulting change in impedance is measured using surface patterned electrodes to detect and quantify the number of cells. We found that the bulk solution conductance increases linearly with the number of isolated cells contributing to solution ion concentration. The method of cell lysate impedance spectroscopy is sensitive enough to detect 20 cells microL(-1), and offers a simple and efficient method for detecting and enumerating cells within microfluidic devices for many applications including measurement of CD4 cell counts in HIV patients in resource-limited settings. To our knowledge, this is the most sensitive approach using non-optical setups to enumerate immobilized cells. The microfluidic device, capable of isolating specific cell types from a complex bio-fluidic and quantifying cell number, can serve as a single use cartridge for a hand-held instrument to provide simple, fast and affordable cell counting in point-of-care settings.
基于细胞的微流控设备在广泛的应用中引起了人们的兴趣。虽然光学细胞计数和流式细胞仪类型的设备已被广泛报道，但通常缺乏灵敏且高效的非光学方法来检测和量化微设备内大面积附着的细胞。我们描述了一种基于测量微流控通道内表面固定细胞释放的离子导致周围介质电导率变化来计数细胞的电学方法。使用低电导率的低渗介质裂解固定的细胞，并使用表面图案化电极测量由此产生的阻抗变化，以检测和量化细胞数量。我们发现，总体溶液电导率随对溶液离子浓度有贡献的分离细胞数量呈线性增加。细胞裂解物阻抗光谱法灵敏度足以检测到20个细胞/微升，为在微流控设备中检测和计数细胞提供了一种简单有效的方法，可用于许多应用，包括在资源有限的环境中测量HIV患者的CD4细胞计数。据我们所知，这是使用非光学设置枚举固定细胞的最灵敏方法。这种能够从复杂生物流体中分离特定细胞类型并量化细胞数量的微流控设备，可以作为手持仪器的一次性试剂盒，在即时护理环境中提供简单、快速且经济实惠的细胞计数。
