A Race to the Bottom: Nano in the Operating Room
Nano-scale tool can improve diagnosis of cancer and other diseases.
The patient is on the operating table, and the surgeon has done a craniotomy, creating an opening into the skull to remove a tumor. It’s a delicate procedure to say the least, but the doctor is searching for more than just tumor cells. The surgeon is also seeking information.
“You want to get information about the type and size of tumor, as well as the potential for treatment; and you want to get this information all at once because you don’t want the patient to go in for multiple surgeries, particularly in the brain,” says Ryan Bailey, University of Illinois professor of chemistry.
That is why Bailey’s lab has developed a sensor that could give surgeons a way to collect significant amounts of information while a patient is under the knife. In fact, the groundwork is being laid to move their nano-scale sensor from the laboratory to the operating room, where it will be tested out in diagnosing one of the most frightening of tumors—brain tumors.
Bailey’s team is working with the Harvard Medical School, preparing the sensor to be tested in their operating room within a few years. During surgery, Harvard neurosurgeon Mark Johnson will remove a piece of a brain tumor, and then a technician will use Bailey’s sensor to extract and rapidly analyze “microRNAs”—very small RNAs that play a key role in gene regulation. Within 15 to 30 minutes, this process will provide information on the sub-type of brain tumor, giving doctors a better idea of how aggressive they should be surgically.
“Some tumors can be treated effectively with chemotherapy or radiation, but other types are not responsive at all,” Bailey says. “If the sensor tells you it’s a non-responsive type of tumor, then you want to be more aggressive surgically.”
The beauty of U of I’s nano-scale “waveguide” is that it can potentially be used with many forms of cancer, as well as other diseases ranging from Alzheimer’s to arthritis. For instance, Bailey’s lab is working to develop a biomarker panel that can identify Alzheimer’s disease in patients before any clinical signs are evident.
The sensor technology is being commercialized by Genalyte Inc., a San Diego-based company. He anticipates that in about a year they will have available their first diagnostic panels to detect disease-specific proteins in the blood, whereas the cancer platform to be used at Harvard will likely take a few years.
The waveguide system developed in Bailey’s lab is based on nano-sized racetracks that confine light. Light speeds round and round the circular track, which is made out of silicon strips only 500 nanometers wide and 200 nanometers tall. When certain biomarkers attach to the racetrack, they change how long it takes for light to complete a lap, and this change can tell technicians a lot about the disease being diagnosed.
Getting information about brain tumors without major surgery is challenging, Bailey says, because the brain is difficult to biopsy; you typically can get only small amounts of tissue compared to tumors in other parts of the body, such as the colon. Their sensor solves this problem because it can extract a lot of information from a very small tumor sample by measuring multiple biomarkers all at once.
“Most conventional diagnostic systems measure the presence, absence, or amount of only one biomolecular marker at a time,” he says. “Currently, if you want to measure multiple biomarkers, you need multiple samples—or one large sample that you divide.
“Our system,” he says, “will soon have the capability to measure over 100 biomarkers from a single small sample. That’s because our sensor chip has many different racetracks, and each one can be made to selectively detect a different biomarker. When a sample is flowed over the sensor array, we measure each of the different biomarkers simultaneously, giving us a lot of information from one sample.”
What’s more, the U of I sensor has already been used to detect markers for liver, pancreatic, colorectal, ovarian, breast, and prostate cancer. Illinois researchers are now targeting new sets of markers selected by their Harvard colleagues.
“Molecular measurement is the future of medical diagnoses,” Bailey says. “We need techniques that can gather lots of information from small amounts of samples and can do it on a cost-effective platform that is highly scalable. That’s the future. That’s where everyone is going, and it’s a race to get there.
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By Doug Peterson