“Doctors need to pinpoint cancer tissue, but that can be hard,” said Liu, a chemistry professor at Michigan Technological University. Test-tube cancer antibodies coupled with special enzymes have been used to highlight malignancies during surgery, since they bind to tumor cells, but they have a drawback.

“They are colorless,” he said. “You can label something, but if you can’t see it, that’s a problem.” Now Liu has developed a probe that could cling to those enzyme-coated antibodies and make them glow under fluorescent light. The journal Analytic Chimica Acta recently published the research.

The fluorescent probe has some appealing medical properties:

• It fluoresces in near-infrared, which can penetrate deep tissues, a property that would allow surgeons to detect malignancies buried in healthy tissue.
• It would result in less “background noise” for surgeons, since other fluorescent tissues typically glow green or blue.
• It is virtually nontoxic at low concentrations.
• It responds quickly to the enzyme at ultra-low concentrations.
• Its fluorescence is stable and long lasting, so it could shine through hours-long cancer operation.

The probe bonds to an enzyme that has a long track record in medical science. Beta-galactosidase has been widely used to label a variety of antibodies that have been used in multiple medical applications, including cancer surgery. “If we could make beta-galactosidase glow brightly during surgery, it could play a major role in improving outcomes,” Liu said.