Wearable device monitors tumour size and displays it in an app

A stretchy sticker that clings to skin can monitor the size of some tumours and send that information to an app. The set-up could lead to real-time continuous tracking of how well certain cancers respond to treatment.

Normally, if someone has a tumour, their doctors can only tell how well it is responding to treatment at regular check-ups. Hsing-Wen Sung at National Tsing Hua University in Taiwan and his colleagues wanted to develop a device capable of providing some of that information at home.

Specifically, they focused on measuring the size of tumours that reside just under the skin. They built a wearable device – which Sung describes as a “smart, flexible sticker” – out of soft and stretchy plastic, which can cling to the skin and conform to the shape of the tumour underneath it.

The plastic was infused with spindle-shaped particles, each about 100 nanometres long, made from oxygen and a silvery metal called hafnium. As the tumour grew, the sticker shifted to accommodate its new size, changing the arrangement of nanoparticles and thus the material’s electrical properties.

The researchers tested the device on mice and found the electrical changes could be used to accurately track the development of tumours roughly the size of a grain of rice over the course of seven days.

Parag Mallick at Stanford University in California says devices like this would allow doctors and patients to more quickly determine whether a treatment is effective and react to any important changes in a tumour’s condition as soon as it happens. However, because it rests atop the skin, the device would not work for tumours deeper inside the body. This means it will require a significant redesign to become universally useful, says Mallick.