Bioengineered skin that lights up to signal disease: living sensor developed in Tokyo

First a life-sized biohybrid hand, then a 'living' skin to clad robots, and now the latest discovery by research teams working in Tokyo: an engineered skin that can light up in the event of illness. In the experiment - conducted on mice by the research team led by Tokyo City University and the University of Tokyo - skin stem cells were genetically modified and transformed into sensors capable of monitoring health indicators in the blood, signalling changes through the production of green fluorescent proteins. The technology, published in the journal Nature Communications, could help monitor the health of animals and humans in the future.

The measurement of biomarkers, such as blood glucose levels and the presence of inflammatory cytokines, is essential to identify chemical, physical or biological processes within the body. Such information plays a crucial role in the early diagnosis and prevention of serious diseases and in the management of lifestyle diseases by providing information on personal health status and disease progression. Therefore, the continuous monitoring of these biomarkers is extremely important, leading to the development of various detection techniques. Conventionally, biomarker detection has mainly been achieved through intermittent blood samples, which allow for accurate measurements. However, it is not suitable for long-term continuous monitoring due to its invasive nature. Recently, with the development of wearable devices, continuous and long-term monitoring of health-related biomarkers using sweat, saliva, tears and interstitial fluid has been intensified. However, no method is capable of monitoring biomarkers inside the body with high selectivity and sensitivity over long periods.

This is the background to the study with the aim of monitoring key molecules that indicate the presence of a disease, inflammatory state or stress without having to take blood and without the use of external devices such as smartwatches. "Conventional approaches are often invasive or provide only snapshots in time," says Hiroyuki Fujita of Tokyo City University and the Japanese company Canon Medical Systems, who coordinated the research. "Our goal was to test a biologically integrated system," he adds, "that would allow continuous detection and intuitive interpretation.

To this end, the authors of the study used genetically modified skin stem cells. Grafted into mice, the engineered skin integrated with the host tissue and was able to translate the body's internal molecular signals into external light signals. Since the sensor is composed of living cells, its functionality is maintained through the natural renewal of the epidermis. During the experiments, the skin-tech continued to work properly for over 200 days.

This system, capable of externally displaying internal information using living cells, was named 'Living Sensor Display'.