A Gold-Coated Sensor Could Reshape Cancer Drug Discovery

Stanford University engineers designed a sensor that can wrap around a tumor and measure its growth or shrinkage in real time—a step forward that will help researchers evaluate cancer drugs and one day even monitor a patient’s cancer progression in real time.

When scientists identify promising candidates for cancer drugs, early-stage testing frequently involves treating immunodeficient mice that develop large tumors. These mice are given the drug and observed over time to measure the drug’s ability at reducing the size or slowing the growth of their tumors. But according to Alex Abramson, a chemical and biomolecular engineer at Georgia Tech who conducted the recent research while at Stanford, these measurements are often made by hand and are not always accurate. Additionally, tools like calipers can only take a two-dimensional measurement of a three-dimensional tumor, leading to further inaccuracies.

Abramson and his colleagues designed a battery-powered device with a flexible sensor that hugs the skin of a mouse to measure the circumference of a tumor, publishing the initial testing of their new design on Friday in the journal Science Advances. A layer of electricity-conducting gold coats the sensor: If a tumor expands, the sensor stretches and miniature cracks form in the gold, decreasing the sensor’s conductivity. If a tumor shrinks, these cracks close up, restoring conductivity. The full sensor costs around $60 to build and takes just minutes to strap onto a mouse. Then, instead of a researcher taking daily measurements, the device can send continuous signals to a cellphone app.

When they compared their device to calipers and another method of charting tumor growth and shrinkage, the researchers found that the sensor’s continuous monitoring detected a reduction in tumor volume due to a cancer drug before either of the other methods.

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“It is a deceptively simple design, but these inherent advantages should be very interesting to the pharmaceutical and oncological communities,” Abramson said in a press release. This method, the researchers wrote in the paper, could supplant the techniques currently used to measure tumors in clinical trials, unlocking a wealth of real-time data that could aid basic cancer research.