Others are impressed by how early on the device appears to detect toxicity in the cells. “When some traditional ways would not give a reading yet, this method already shows the toxic effect,” says Erkki Ruoslahti, who studies cell biology and cancer at the Burnham Institute for Medical Research in La Jolla, CA. “This may give a quick, high-throughput answer in a shorter time and with much less effort.”
Sailor says that the simple technique could save pharmaceutical companies time and money because they could eliminate toxic compounds early in the drug-testing process. “It’s a tool to speed up the process of drug discovery,” he says, adding that it would augment current cellular tests.
Right now, scientists screen new drugs before human trials with in-vitro tests on rat liver cells. In these tests, they introduce the drug into liver cells grown in Petri dishes placed in incubators. At regular time intervals, they have to analyze the cells under microscopes, to find out how many cells are dead. To do that, they must add chemicals that either modify or kill the remaining cells. Furthermore, every experiment needs hundreds of Petri dishes and cell cultures, adding to the cost. “You’d rather make measurements in real time, and instead of pulling a dish out every half hour, have something monitoring cells in the incubator,” Sailor says.
Jonathan Dordick, professor in the department of chemical and biological engineering at the Rennselaer Polytechnic Institute, says the technique’s big advantage is that it can monitor a toxin’s gradual effect on cells. “This is useful because many compounds are not immediately toxic,” he says. It allows, he suggests, a simple way to follow the health of the same group of cells over time without altering or killing them.
Furthermore, Sailor says the new device could allow multiple experiments simultaneously. A quarter-sized porous silicon chip could contain up to 10,000 different test sites, each made to reflect light at a specific frequency. One could then put small bunches of cells on the sites and test the toxic effect of various toxin concentrations or drug combinations.
The team has a research agreement with the Hitachi Chemical Research Center in Irvine, CA, which will attempt to commercialize the technology.