As cancer drugs are developed, one important process the drug goes through is testing in experimental animals. The use of animal models to test the efficacy of drugs, produces results that most closely resemble what would occur in humans. Laboratory mice are often the chosen animal model to test the efficacy and toxicity of cancer drugs, and one way this is done is by grafting human-derived tumors onto the mouse. Researchers can then administer experimental cancer drugs to the mice and measure whether the tumor changes in size, with the hope that the new drug will shrink the tumor.
The current tools used to assess changes in tumor size in experimental mice are not particularly advanced. Typically, researchers compare changes in tumor size across groups of tumor-ridden animals who are either given an experimental anti-cancer drug or a not. Then a researcher will manually assess tumor size using hand calipers and record the size of the tumor. However, this method can be difficult, filled with human error, and labor-intensive. Now, researchers form Stanford University’s Department of Chemical Engineering have developed a new wearable sensor that can detect very small changes in tumor size in real-time.
The wearable sensor is flexible and thin and can send real-time measurements directly to a monitoring device such as a smartphone. Importantly, the sensor has the sensitivity to detect changes in tumor size down to the micrometer, or one-hundredth of a millimeter. The researchers have named the device “FAST” for “Flexible Autonomous Sensor measuring Tumors,” and believe this device can change the way in which researchers test the efficacy of cancer drugs.
The research team tested their sensor in two separate mouse models of cancer. In the experiments, the researchers provided groups of mice who had tumors with an anti-tumor drug or a vehicle treatment. Then the researchers monitored the size of the tumors following drug administration. Remarkably, the sensor was able to discern differences in tumor sizes between drug and vehicle treated tumors in as little as 5 hours after the anti-tumor drugs were administered.
The FAST sensor is a polymer skin patch that is coated on the top with a layer of gold. When the sensor expands or shrinks, it forms small cracks in the gold layer which changes the electrical conductivity of the sensor. And as the number of cracks increase or decrease, the sensor’s conductivity changes, allowing the device to determine small changes in tumor size to which it is attached. Dr. Alex Abramson, the lead author of the study said, “[the sensor] is a deceptively simple design…[but] FAST could significantly expedite, automate and lower the cost of the process of screening cancer therapies.”
Wearable sensors are becoming increasingly common in health monitoring. As reported previously wearable sensors can help to accurately monitor anything from heart and respiratory health to overdose detection. However, FAST it the first of its kind that can monitor tumor size changes in real time and may help greatly transform the field of cancer treatment.