Universities collaborate on novel MS technology

A Purdue University team, led by Graham Cooks, is teaming up with collaborators at Harvard to test the abilities of a desorption electrospray ionisation (DESI) mass spectrometer during brain surgery.

The group are hoping to compare the system with the gold standard - traditional analysis of tissue samples by pathologists.

“These procedures are among the longest of all surgical operations, and this new technology offers the promise of reducing the time patients are under anesthesia,” Cooks explained.

“DESI can analyse tissue samples and help determine the type of brain cancer, the stage and the concentration of tumor cells. It also can help surgeons identify the margins of the tumor to assure that they remove as much of the tumor as possible. These are early days, but the analysis looks promising.”

Cooks’ lab is also in the process of developing a “PaperSpray ionisation” mass spectrometer.

The researchers are using this device to monitor the levels of chemotherapy drugs in patients’ blood in real time.

“Many cancer drugs have relatively narrow therapeutic ranges, so they need to be in the blood at certain levels to work properly,” he noted. “But at present, that information is not obtained in real time, so a patient could end up with too little or too much of the drug in his or her body.”

Both the DESI and PaperSpray mass spectrometers work in a similar way. To weigh chemicals, mass spectrometers need to ionise, or give a positive or negative charge to a substance.

Mass spectrometers usually do this inside the instrument under a vacuum without air. But DESI and PaperSpray can do this so-called ionisation process out in the open.

This allows scientists much more flexibility. DESI and PaperSpray also can do analyses without separating out all of the chemicals in a sample first, which provides quick results.

They are also very easy to operate. “You just point and shoot,” said Cooks.

Currently, Cooks’ team is testing to see whether DESI can provide different information compared to what pathologists can provide by looking at human tissues under a microscope.

In addition, the researchers are testing PaperSpray on patients’ blood samples, though Cooks points out that the device also could measure the levels of drugs of abuse or pharmaceuticals in urine or other body fluids.