Ongena Kathleen, Das Chandreyee, Smith Janet L, Gil Sónia, Johnston Grace
Bioscience Division, Millipore Inc.
J Vis Exp. 2010 Nov 26(45):2204. doi: 10.3791/2204.
Counting cells is often a necessary but tedious step for in vitro cell culture. Consistent cell concentrations ensure experimental reproducibility and accuracy. Cell counts are important for monitoring cell health and proliferation rate, assessing immortalization or transformation, seeding cells for subsequent experiments, transfection or infection, and preparing for cell-based assays. It is important that cell counts be accurate, consistent, and fast, particularly for quantitative measurements of cellular responses. Despite this need for speed and accuracy in cell counting, 71% of 400 researchers surveyed(1) who count cells using a hemocytometer. While hemocytometry is inexpensive, it is laborious and subject to user bias and misuse, which results in inaccurate counts. Hemocytometers are made of special optical glass on which cell suspensions are loaded in specified volumes and counted under a microscope. Sources of errors in hemocytometry include: uneven cell distribution in the sample, too many or too few cells in the sample, subjective decisions as to whether a given cell falls within the defined counting area, contamination of the hemocytometer, user-to-user variation, and variation of hemocytometer filling rate(2). To alleviate the tedium associated with manual counting, 29% of researchers count cells using automated cell counting devices; these include vision-based counters, systems that detect cells using the Coulter principle, or flow cytometry(1). For most researchers, the main barrier to using an automated system is the price associated with these large benchtop instruments(1). The Scepter cell counter is an automated handheld device that offers the automation and accuracy of Coulter counting at a relatively low cost. The system employs the Coulter principle of impedance-based particle detection(3) in a miniaturized format using a combination of analog and digital hardware for sensing, signal processing, data storage, and graphical display. The disposable tip is engineered with a microfabricated, cell- sensing zone that enables discrimination by cell size and cell volume at sub-micron and sub-picoliter resolution. Enhanced with precision liquid-handling channels and electronics, the Scepter cell counter reports cell population statistics graphically displayed as a histogram.
对于体外细胞培养而言，细胞计数通常是必要但繁琐的步骤。一致的细胞浓度可确保实验的可重复性和准确性。细胞计数对于监测细胞健康状况和增殖速率、评估永生化或转化情况、为后续实验接种细胞、转染或感染以及准备基于细胞的分析都很重要。细胞计数准确、一致且快速非常重要，特别是对于细胞反应的定量测量。尽管在细胞计数方面需要速度和准确性，但在接受调查的400名使用血细胞计数器进行细胞计数的研究人员中，有71%的人[情况如下]。虽然血细胞计数法成本低廉，但它费力且容易受到用户偏差和误用的影响，从而导致计数不准确。血细胞计数器由特殊光学玻璃制成，在其上以特定体积加载细胞悬液并在显微镜下进行计数。血细胞计数法中的误差来源包括：样品中细胞分布不均匀、样品中细胞过多或过少、对于给定细胞是否落在定义的计数区域内的主观判断、血细胞计数器的污染、用户之间的差异以及血细胞计数器填充率的差异[2]。为了减轻与手动计数相关的繁琐，29%的研究人员使用自动细胞计数设备进行细胞计数；这些设备包括基于视觉的计数器、利用库尔特原理检测细胞的系统或流式细胞仪[1]。对于大多数研究人员来说，使用自动化系统的主要障碍是这些大型台式仪器的价格[1]。Scepter细胞计数器是一种自动手持式设备，它以相对较低的成本提供库尔特计数的自动化和准确性。该系统采用基于阻抗的粒子检测的库尔特原理[3]，以小型化形式使用模拟和数字硬件的组合进行传感、信号处理、数据存储和图形显示。一次性吸头设计有微加工的细胞传感区，能够以亚微米和亚皮升分辨率通过细胞大小和细胞体积进行区分。通过精密液体处理通道和电子设备进行增强，Scepter细胞计数器以直方图的形式图形化显示细胞群体统计数据。
