Bionic breast seeks to return sensation after mastectomy

The Bionic Breast Project is bringing together neuroscientists and biomaterials engineers to build an implantable device that will restore sensation to the breast after mastectomy and reconstructive surgery. Electronic components will connect to the nervous system through an array of electrodes called a C-FINE device that wraps around the intercostal nerves in the chest. In trials, small, capped electrical leads will be exposed under the patient’s armpit, with researchers testing the device by delivering electrical impulses through the leads and patients reporting on the corresponding sensations.

Roughly a third of those diagnosed with breast cancer undergo a mastectomy, where one or both breasts are surgically removed from the body. As well as leaving many patients - up to 77 per cent - with reduced sexual function, the rapid decision-making processes often required can also be a source of trauma, according to Dr Stacy Tessler Lindau, director of the Program in Integrative Sexual Medicine at the University of Chicago Medical Center.

“For most women, it's less than a few weeks between the moment a doctor says, ‘You have breast cancer’ and having a mastectomy,” she said.

“Even if their breasts are cosmetically restored, women still have many of the same experiences as a person who loses a limb, like feeling it’s no longer part of their body, total loss of sensation and even pain. For many people, it’s not just a physical loss, but also a psychological and even existential loss.”

The bionic breast will feature a flexible pressure sensor that can stretch and flex while still maintaining its sensitivity. The outside layers of the sensor are made of stretchy, conductive nanoparticle paste and elastomer. When pressure is placed on the sensor, tiny pyramid structures on the inside layer compress slightly, connecting with electrodes that send signals about the pressure level.

“The natural movements that create changes in the shape of muscles and skin will also create changes in the sensor,” said Sihong Wang, PhD, Assistant Professor of Molecular Engineering at the UChicago Pritzker School of Molecular Engineering.

“The overall goal is to create a sensor that is as soft and flexible as biological tissue, but with a chemical design that is compatible with the immune system that we can leave in the body of the patient for the rest of their life.”

The project has already been running for several years but recently received a $3.99m funding injection from the National Institutes of Health (NIH) in the US. According to Lindau, the project can help fill a crucial but unaddressed gap in quality of life after breast cancer treatment and surgery, as well as help improve communication around the effects of mastectomy, particularly on sexual function.

“We interview people who say, ‘I want the surgeon to tell me clearly that most of the nerves are being surgically removed along with the breast,’” said Lindau. “Patients want frank but compassionate communication with the recognition that what’s being lost is not just the feeling of sensation in the breast, but also the functioning of an important sexual organ.”