Chemical tests of cell growth enter third dimension

September 15, 2006

Ohio State University researchers have developed two new technologies for measuring cell growth in the laboratory.

The first patent-pending technology provides a way for researchers to easily tell if cancer cells in the laboratory are responding to an anti-cancer drug. The second -- because it tests several sets of cells at once -- allows for the simultaneous testing of different dosages, or the effect of a single drug on different kinds of cells taken from the body.

Shang-Tian Yang, professor of chemical and biomolecular engineering at Ohio State, and his colleagues described the two technologies Wednesday and Thursday at the American Chemical Society Fall National Meeting in San Francisco.

For more than a decade, Yang's team has been developing three-dimensional methods for growing cells for laboratory testing. His fibrous-bed bioreactor (FBB) is a device that allows cells to grow in natural 3D bundles. In the body, cells cling to supportive tissues as they grow; inside the FBB, they cling to strands of polyester fibers.

For the first of the two new technologies, Yang took the basic concept behind the FBB and combined it with laboratory testing methods that normally only grow cells in two dimensions.

Such tests are normally done on cells in trays containing many tiny wells. Each well contains a growth medium and some cells, and a protein that will cause growing cells to fluoresce. Researchers test a drug by adding it to a well. If the cells continue to fluoresce, that means that the cells are still reproducing, and the drug isn't effective at controlling growth.

The problem is how to measure the amount of fluorescence, to quantify how much the cells are growing. Fluorescing cells don't look very bright in the well, because they grow as a thin film layer that is essentially two-dimensional. Researchers get around this problem by removing the cells from the well and counting them one by one under a microscope.

It's a long and tedious process.

"Our idea is very simple," Yang said. "We wanted to intensify the signal so that it could be read inside the well, by cultivating the cells in three dimensions."

Yang and his team created a device that uses standard well plates in a new way. In one well, they plant cells on one of their 3D scaffolds. The surrounding eight wells contain only growth medium.

The 3D glob of cells in the middle well glows brighter than a 2D film, due to a specific optical effect, Yang said. The surrounding empty cells provide a darker background that lets the fluorescence signal be measured even more easily.

"You can use this as a device to monitor a drug's effect, whether you want to stimulate or inhibit cell growth," Yang said. "We have used it on colon cancer cells and mouse embryonic stem cells. And in both cases, we found a very good relation between cell growth and fluorescence intensity."

The device can be used with standard well plates, though nine wells are required for each test instead of one. He and his team are expanding the technology from 96-well plates to 384-well plates, and are working on their own custom plate design.

There is an advantage to using more wells: The eight empty wells supply nutrients to the cells in the middle well, so tests can run for up to two weeks without researchers having to replenish the growth medium.

"If you replenish the medium, you could essentially grow cells indefinitely," Yang said.

The second new technology to come from Yang's lab is a microfluidics platform that allows for testing of many types of cells or drug dosages at once. Tiny pipes connect wells that contain cells growing in 3D. The drug to be tested is pumped from a common reservoir into the pipes.

Each well could receive a different dosage of the same drug. Or, researchers could plant cells from different organs in each well, and see how each kind of cell reacts to the same dosage -- a quick way to detect a drug's potential side effects on the body.

"The trick is to use one pump for everything, and control the fluid distribution though all the channels," Yang said. While he has worked out an initial design, he would like to join with a commercial microfluidics manufacturer to develop the technology further.

The university is expecting to license both technologies.

Source: Ohio State University

Explore further: Discovery could lead to biological treatment for common birth defect

Related Stories

Nano packages for anti-cancer drug delivery

March 18, 2015

Cancer stem cells are resistant to chemotherapy and consequently tend to remain in the body even after a course of treatment has finished, where they can often trigger cancer recurrence or metastasis. A new study by researchers ...

Researchers use liquid inks to create better solar cells

September 17, 2014

(Phys.org) —The basic function of solar cells is to harvest sunlight and turn it into electricity. Thus, it is critically important that the film that collects the light on the surface of the cell is designed for the best ...

Recommended for you

Earth flyby of 'space peanut' captured in new video

July 31, 2015

NASA scientists have used two giant, Earth-based radio telescopes to bounce radar signals off a passing asteroid and produce images of the peanut-shaped body as it approached close to Earth this past weekend.

How bees naturally vaccinate their babies

July 31, 2015

When it comes to vaccinating their babies, bees don't have a choice—they naturally immunize their offspring against specific diseases found in their environments. And now for the first time, scientists have discovered how ...

Image: Hubble sees a dying star's final moments

July 31, 2015

A dying star's final moments are captured in this image from the NASA/ESA Hubble Space Telescope. The death throes of this star may only last mere moments on a cosmological timescale, but this star's demise is still quite ...

Exoplanets 20/20: Looking back to the future

July 31, 2015

Geoff Marcy remembers the hair standing up on the back of his neck. Paul Butler remembers being dead tired. The two men had just made history: the first confirmation of a planet orbiting another star.

New blow for 'supersymmetry' physics theory

July 27, 2015

In a new blow for the futuristic "supersymmetry" theory of the universe's basic anatomy, experts reported fresh evidence Monday of subatomic activity consistent with the mainstream Standard Model of particle physics.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.