May 6, 2024

Observing Cells in Their Natural State with Digital Holographic Cytometry

Visualization is an essential element for studying cellular morphology and function. Living cells are clear and mainly made up of water, making them nearly difficult to observe utilizing traditional light microscopy. One option for this issue is to stain cells with dyes, but while this process produces enough contrast for visualization, it normally eliminates the specimens. Current technological advances have actually made real-time, live-cell visualization much more broadly accessible, and scientists are taking benefit of this to see both cellular end-states and the transitory processes essential to reach them. Fluorescent labeling is one alternative for live-cell imaging. However, while this technique enables researchers to observe living cells and picture proteins or structures of interest, its intrusive nature affects cell physiology. In addition, fluorescent labeling is not fit for long-term monitoring due to photobleaching.1 Phase contrast microscopy (PCM) uses a non-invasive option to labels and dyes. When light passes through translucent objects such as cells, it undergoes a stage shift relative to the illuminating (background) light. PCM catches these phase shifts, creates a stage shift gradient, and transforms that into strength variations for visualization. The method is qualitative, not quantitative, suggesting that the produced images are not ideal for making measurements.2 Introducing Quantitation Quantitative stage imaging (QPI) is a label-free, non-invasive, and non-destructive visualization method that can record images in 2D (single aircraft), 3D (multi-plane), and 4D (multi-plane throughout time) with nanoscale level of sensitivity for morphology and characteristics.3 In QPI, light is refracted as it passes through a sample (the item beam). This altered light then combines with light that has not passed through the sample (the reference beam), producing a disturbance pattern that yields a hologram when it is identified by a sensor.2,4 Indeed, holographic microscopy– and more just recently, digital holographic microscopy (DHM)– is one of the most commonly used form of QPI.Researchers initially used DHM to take a look at living cells around 2004-2005,5,6 and it rapidly ended up being popular owing to its non-invasiveness, extremely high resolution, capability to image morphological functions not visible via other methods, potential for envisioning cellular characteristics, and ability to provide quantitative measurements.7 Digital holographic cytometry– the usage of DHM for cellular research study– can be automated, is expense efficient, can high-throughputs, and, most critically, does not hurt the cells. Scientist hence have actually utilized DHC to study a broad variety of cell types, interactions, and processes.7 The HoloMonitor Solution Long-term imaging of live cells requires to take place in a controlled environment to ensure cells are acting in a physiologically relevant way. It also needs to be non-invasive to avoid activating cellular actions and automated to limit environmental perturbations. Ideally, it should also be compact in order to fit inside incubators, cost effective, and simple to use. The HoloMonitor ® live cell imaging system from PHI is a complete label-free, single cell resolution imaging option. Consisted of the compact HoloMonitor cell culture microscopic lense and the tailor-made and powerful App Suite software application, the system naturally fits within typical standard cell incubators, making it ideal for cell culture tracking, cell counting and quality control, and live cell experiments such as injury healing and motility assays.ReferencesS. Aknoun et al., “Quantitative stage microscopy for non-invasive live cell population tracking,” Sci Rep, 11:4409, 2021. Z. El-Schich et al., “Quantitative stage imaging for label-free analysis of cancer cells– concentrate on digital holographic microscopy,” Appl Sci, 8:1027, 2018. Y. Park et al., “Quantitative phase imaging in biomedicine,” Nature Photon, 12:578 -89, 2018. L. Sternbæk et al., “Digital holographic cytometry: Macrophage uptake of nanoprobes,” Imaging and Microscopy, 1:21 -23, 2019. P. Marquet et al., “Digital holographic microscopy: a noninvasive contrast imaging technique enabling quantitative visualization of living cells with subwavelength axial accuracy,” Opt Lett, 30( 5 ):468 -70, 2005. D. Carl et al., “Parameter-optimized digital holographic microscopic lense for high-resolution living-cell analysis,” Appl Opt, 43( 36 ):6536 -44, 2004. K. Alm et al., “Cells and holograms– holograms and digital holographic microscopy as a tool to study the morphology of living cells,” in Holography– Basic Principles and Contemporary Applications, E. Mihaylova, ed., London: IntechOpen, 2013.

Researchers thus have used DHC to study a wide range of cell types, interactions, and processes.7 The HoloMonitor Solution Long-term imaging of live cells requires to take location in a regulated environment to guarantee cells are acting in a physiologically pertinent way. The HoloMonitor ® live cell imaging system from PHI is a total label-free, single cell resolution imaging option. Comprised of the compact HoloMonitor cell culture microscope and the custom-made and effective App Suite software application, the system naturally fits within common standard cell incubators, making it ideal for cell culture tracking, cell counting and quality control, and live cell experiments such as injury healing and motility assays.ReferencesS. K. Alm et al., “Cells and holograms– holograms and digital holographic microscopy as a tool to study the morphology of living cells,” in Holography– Basic Principles and Contemporary Applications, E. Mihaylova, ed., London: IntechOpen, 2013.