In the United States, over a million new cases of cancer are reported each year. Yet developing drugs to effectively treat cancers is an arduous and time-consuming process, often requiring researchers to test thousands of potential drugs before one proves successful for human patients.
Now, engineers at Stanford University and collaborators at Stanford Medicine have devised an easier, more effective way to test the efficacy of these drugs. And you wear it.
It's a small device with a sensor that adheres to the skin. The sensor, dubbed FAST (for Flexible Autonomous Sensor measuring Tumors), tracks in real time the changing size of tumors located in the layer of tissue below the skin. The information is transmitted from the device to a smartphone app.
There are plenty of other ways to monitor tumor regression, but there are also many shortcomings, the authors wrote in a paper published Sept. 16 in Science Advances.
"In some cases, the tumors under observation must be measured by hand with calipers," said first author Alex Abramson, PhD, who was previously a postdoc in the lab of Zhenan Bao, PhD, at the Stanford School of Engineering.
This is far from ideal, and Abramson hopes FAST can offer a more accurate, speedy and inexpensive measure of the impact of cancer drugs and eventually get them to market.
A special gold sensor
Abramson and his colleagues tested the device by sticking FAST sensors on mice with subcutaneous tumors -- tumors in the layer of tissue below the skin. They found that, unlike many other tumor measurement approaches, the sensor provided continuous monitoring of the mass and accurately measured the tumor's change in shape and size.
It is also noninvasive and can operate on its own, allowing the mice to move unhindered by wires and obviating the need for scientists to handle them to get each measurement. Additionally, the FAST devices are reusable and cost only around $60 to assemble.
The sensor is composed of a thin, flexible substance coated in a layer of gold, which can stretch and shrink based on the size of the tumor. It connects to a small device, carried in a backpack, that tracks how the sensor stretches or shrinks and converts that information to electrical conductivity. When the gold stretches, it develops cracks that decrease its electrical conductivity -- indicating a growing tumor. When it shrinks, the cracks "heal," and the conductivity improves, implying a shrinking tumor.
Hurdles remain, such as the concern that the sensor itself may constrict the tumor. But Abramson and his colleagues noted there are ways to circumvent this by making the sensor as supple as real skin.
Abramson described FAST as a "deceptively simple design." "These inherent advantages should be very interesting to the pharmaceutical and oncological communities," he said. "FAST could significantly expedite, automate and lower the cost of the process of screening cancer therapies."
This story was adapted from the Stanford University News Center.
Photo by Vitanovski