UC San Diego has developed a petri dish that can quickly and cost-effectively determine a cell’s ‘health’ under different conditions. Let’s just say it’s smarter than your average petri dish. From the press release:
Their invention, described in the June 20 issue of Langmuir, a physical chemistry journal published by the American Chemical Society, uses porous silicon crystals filled with polystyrene to detect subtle changes in the sizes and shapes of the cells.
“You could also in principle use this to identify metastatic cancer cells circulating in a patient’s blood,” Sailor adds, “by putting blood samples from a patient onto the crystal and comparing them to normal blood samples.”
In addition, says Michael Schwartz, a postdoctoral scholar in Sailor’s laboratory and the first author of the paper: “The potential of our technique for fundamental studies of cell toxicity is exciting, Since we can monitor cells in real time without removing them from their natural environment, the observed changes provide a time course for performing more detailed tests to find out why drugs are toxic.”
The scientists constructed their Smart Petri Dish by first fabricating silicon crystals with nanometer-sized holes. This enabled them to produce a photonic crystal, capable of controlling light within the structure analogous to the way that semiconductors transmit electricity through computer chips. By attaching rat liver cells to the polystyrene within the crystals and measuring the scattering of light with a sensitive spectrometer, they were able to detect small changes in the shapes of the cells as they reacted to toxic doses of cadmium chloride and acetaminophen.
“As these cells shrivel up in response to a toxin, they scatter light better, much like fog on a car windshield, allowing us to quickly detect which drugs may have adverse side effects when taken in combination with another,” says Sailor. “You’re not supposed to drink alcohol when taking acetaminophen, because the combination of the two is much more toxic to your liver than either drug individually. This is known as an adverse drug-drug interaction and it is very expensive and time-consuming to screen a new drug candidate with all the possible combinations of drugs that a patient may be taking. The Smart Petri Dish allows us to perform a large number of such toxicity assays simultaneously, in order to provide an early indication of the particular physiological or pharmacological conditions that need more in-depth study.”
“Although we performed these experiments on rat cells, this technology can be easily extended to human cells,” says Sangeeta Bhatia, a professor of bioengineering at UCSD now at MIT, who also participated in the study. “This is important because we know that the enzymes that metabolize drugs-the P450 family-are very different in animal and humans. This is one of the reasons many drugs clear animal testing but end up toxic in patients. This type of sensor could help us predict human liver responses without patient exposure.”