BioTek July 2019 - 8

Imaging Assays for
Cell Proliferation
Advances in microscopy, cell imaging, and robotics are facilitating
assessment of the long-term proliferation of cells.
Caitlin Smith
Cell proliferation is often measured using microplate readers in quick, snapshot-in-time endpoint
assays of the cells in the sample. But as cell culture techniques and technology progress hand in
hand, scientists are becoming increasingly adept
at maintaining healthy cells in long-term cultures.
Such cultures are particularly useful for studying
the long-term effects of drug candidates such as
antiproliferative compounds under development
as anticancer agents.

indicator, phenol red is often included in media
for housekeeping purposes, simply to show at a
glance-by a change in color-if the pH of the media has changed from physiological conditions. A
color change is usually the result of bacterial overgrowth, which causes the media to turn yellow as
the media acidifies from bacterial waste products.
But metabolic waste produced by mammalian cells
can also lower pH, so in the absence of bacterial
contamination, the change in media color can be
used to monitor cell health of long-term mammalian cultures. Such an application can be pivotal in
long-term experiments that benefit from the ability
to monitor cell health over time, such as long-term
proliferation assays.

Studying the changes that occur in cultured cells
over longer time frames (instead of brief snapshots
in time) requires different tools. Today, advances in
microscopy, cell imaging, and robotics are offering
scientists the new tools and assay techniques they
need to assess the long-term proliferation of cells.

BioTek Instruments recently demonstrated that
their Cytation™ 5 Cell Imaging Multi-Mode Reader
enables researchers to measure the media pH
during live cell experiments while simultaneously
using fluorescence imaging to count cells expressing GFP. "The Cytation 5 is part microplate reader
and part widefield microscope, so it can count proliferating cells and monitor media pH in the same
automated workflow," says Peter Banks, scientific
director of BioTek Instruments.

Coupling absorbance-based
media pH measurements with
fluorescence imaging to monitor
long-term cell proliferation
A commonly used addition to cell culture media,
phenol red dye, takes center stage in helping to
monitor cell health in long-term cultures. As a pH

https://www.biotek.com/assets/tech_resources/Phenol%20Red%20Live%20Cell%20App_Note.pdf

BioTek July 2019

Table of Contents for the Digital Edition of BioTek July 2019