It should be possible to detect toxins and cancer molecules with the magnetic biosensor using the same type of chip, Wang says. The trick is to bind a magnetic nanoparticle to the molecules so the electronic signature can be detected.

Because the chip has more than 1,000 sensors, Wang says, it is capable of monitoring many different types of molecules at one time. And integrating the electronic circuitry into the magnetic sensor array allows each sensor to provide a distinct output. The advantage here, he says, is that the chip design could be used to look for a number of different toxins, diseases, and DNA sequences.

With recent advances in high-density data storage, magnetic biosensors have become sensitive enough to use in biochips, says Lloyd Whitman a scientist at the U.S. Naval Research Laboratory in Washington, D.C. who is a pioneer in the field. Wang's work, in particular, shows that the magnetic technology can be used to make large arrays of sensors on biochips, Whitman says. "It's scalable," he says, and each sensor can provide a distinctive electronic signature.

The biochip still needs to be tested with many non-DNA molecules to be useful for disease and toxin detection, Wang says. But within the next few years he expects that the technology will find its way into clinical trials.