First-of-Their-Kind Sensors Monitor Cancer Like a Live Broadcast

Medicine has made major advances against cancer. Over the past thirty years, the risk of dying from cancer after diagnosis has fallen by 32% in countries with advanced healthcare, thanks to factors including earlier diagnosis and improvements in drug treatment.

Although improved survival is encouraging, cancer remains common. In our country, it is the second most common cause of death after cardiovascular disease.

A tool presented in a new study could provide better information about how tumours respond to treatment.

It can report tumour growth or shrinkage in real time and send the results wirelessly to a smartphone for analysis. This proof-of-concept device, used in animal experiments, is the first of its kind.

Dr Alex Abramson, a study co-author from Georgia Tech’s School of Chemical and Biomolecular Engineering, says: “Our technology is the first bioelectronic device to monitor tumour regression, or shrinkage, and the first technology able to monitor tumours in real time.”

The sensor uses technology similar to other flexible, skin-like wearables that capture biometric data, including through sweat. What makes it unique, however, is the chemical element that enables it to detect tumour changes: gold.

Gold is useful because it is flexible and conductive. In this device, a gold-infused sensor is attached to the skin around the tumour being measured. If the tumour grows, the gold coating stretches and cracks, becoming less conductive. As the tumour shrinks, the cracks close and conductivity increases.

“We measure these changes in conductivity and translate them into measurements of changes in tumour volume.”

Currently, the most common ways to measure tumours are PET-CT cancer scans, callipers and bioluminescence imaging (BLI). These measurements are useful and accurate but are generally taken every few days or weeks. Measuring treatment response with PET-CT requires at least 2 weeks after the last treatment. The new sensor captures updates every five minutes and can detect extremely small changes that callipers and BLI cannot.

Dr Abramson says of the new device:

“Our sensor will allow us to understand the short-term effects of medicines on tumours better and offer scientists and healthcare professionals a more streamlined way to screen drugs that could become future treatments.”

The sensors are already being used in animal studies, but human use is still several years away.

For something containing gold, they also cost less than might be expected. Discussing the cost, Dr Abramson says: “A researcher can make the sensor for less than 60 dollars.”

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Figure: Flexible autonomous sensors measuring tumour volume regression.

( A ) FAST (fast) technology. ( B ) Light microscopy of the fractured gold strain sensor under different strains. Scale bars: 20 μm. ( C ) An application recording changes in sensor resistance. ( D ) FAST includes a printed circuit board (PCB) and a backpack holding the strain sensors on the mouse. ( E ) Changes in sensor resistance when stretched in 10 μm increments from a 50% pre-strain. ( F ) Fold change in resistance of stretched sensors (individual curves from 10 sensors; thick line, mean). ( G) Force needed to strain sensors with different SEBS substrate thicknesses (individual curves from 12 to 13 sensors; line, mean ± SD).