Label-Free and Fluorescence Timelapse Live Cell Imaging and Cytometry Seminar

Ptychography, Phasefocus, Livecyte

The Livecyte system will be available for tests from 17 -21 July. The system will be installed in the Adrian Building Wolfson Foundation microscope room. Please let me know (krs5) if you did not attend the seminar but would like to test the system.

Background:

For many cell imaging studies the contrast in the images is simply too low to analyse the cells in vivo. Often we add a fluorescent marker and/or using Differential Interference Contrast (DIC) or Phase Contrast imaging to visualize our cells of interest. Adding a fluorescent marker requires manipulation and interruption of cell culture conditions potentially effecting normal cell function and cell division process. For DIC/Phase contrast images it has proven difficult to automatically track individual cells using these techniques (see Marrison et al. Fig 2) nor is it easy to extract quantitative information. As a result we often look at the whole population, like in wound healing assays, or we manually track a few individual cells in each sample. This is time consuming and we through a lot of data away. To better understand the impact of drug treatments, genetic modifications or environmental factors, it is important to identify and observe all cells in a mixed population.

Recently some new label free cell imaging techniques have been developed. One of these new contrast technique is called Ptychography. The company Phasefocus has developed a screening station called Livecyte using this new Quantitative Phase Imaging technique. It produces high contrast, high fidelity images which are artefact free and quantitative, without the need for cell labelling or high intensity light imaging. The system uses for detection of label free cells a laser power several magnitudes lower than used in traditional fluorescence microscopes, allowing for long term live cell imaging, longer than 1 week if required. It allows the quantification of for example cell volume and thickness, length/width, total dry mass, mitotic index, proliferation rate, speed and displacement. The analysis software included allows to identify and track 100s of individual cells in a screen allowing to find subpopulations within the culture.

Individual cell segmentation

 Figure 1: Individual cell segmentation and metrics calculated relating to each population using the Livecyte’s Cell Analysis Toolbox displays distinct phenotypes (Phasefocus website).

An additional advantage of this technique is that the images are always in focus and not influenced by external vibration.

Lately, this technique has been combined with fluorescence imaging which will allow to identify specific cell, organelles etc within the sample if required and allows fluorescent screening as well as label free screening of live and fixed samples.

If there is enough interest we will organize a demonstration of the Livecyte in a few weeks time where people can test the system using their own cells. This system can potentially replace our aging ScanR/CellR system adding label free imaging in the mix as well.

Links: 

Phasefosus.

Joanne Marrison, Lotta Räty, Poppy Marriott & Peter O’Toole. Ptychography – a label free, high-contrast imaging technique for live cells using quantitative phase information. Nature Scientific Reports 3, August 2013, Article number: 2369 doi:10.1038/srep02369

Label-free imaging to study phenotypic behavioural traits of cells in complex co-cultures. Rakesh Suman, Gabrielle Smith, Kathryn E. A. Hazel, Richard Kasprowicz, Mark Coles, Peter O’Toole & Sangeeta Chawla. Nature Scientific Reports 6, February 2016, Article Number: 22032 doi:10.1038/srep22032

Characterising live cell behaviour: Traditional label-free and quantitative phase imaging approaches. Richard Kasprowicz, Rakesh Suman, Peter O’Toole. The International Journal of Biochemistry & Cell Biology, 84 (2017) 89 - 95 doi.org/10.1016/j.biocel.2017.01.004.

Share this page: