Method found to detect hypoxia in real time

CHICAGO, Dec. 8 (Xinhua) -- Researchers at the University of Illinois (UI) have developed a photoacoustic molecular probe to find hypoxic spots noninvasively in real time.

Areas of hypoxia, or low oxygen in tissue, are hallmarks of fast-growing cancers and of blockages or narrowing in blood vessels, such as stroke or peripheral artery disease.

The study has been published in the latest issue of the Nature Communications.

The advantage of the newly developed method is believed to be less invasive, of higher resolution and lower cost.

The molecular probes only become active when oxygen is lacking.

When excited by light, the oxygen-sensitive molecular beacon UI researchers produce an ultrasound signal, allowing direct 3-D imaging of hypoxic areas, a process called photoacoustic imaging.

UI researchers have tested the system on cell cultures and in live mice with breast cancer and mice with constricted arteries in their legs, and found that the photoacoustic method could find hypoxia mere minutes after a mouse's artery was constricted, showing promise for quickly finding stroke sites or blood clots in deep tissue.

In the mice with cancer, the probes enabled detailed 3-D ultrasound imaging of hypoxic tumors.

"We could give a doctor a three-dimensional, real-time view into the tissue to guide surgical procedures and treatment plans," said UI chemistry professor Jefferson Chan, the leader of the study.

"This gives scientists and physicians a way to noninvasively look inside tumors and determine whether a patient's tumor is hypoxic and they would be a good candidate for a new drug," Chan said.

Current methods for detecting hypoxia in tissue can only identify chronic hypoxia, and thus cannot help doctors find aggressive cancers or acute conditions like a stroke that require immediate intervention. Enditem