Japanese scientists have developed an implantable, biocompatible material that functions like a check engine light for the human body, illuminating when it detects certain biological parameters outside expected ranges.
The research team behind the implantable ‘living’ skin suggests their material, which is powered by the human body’s natural functions and requires no external power source, could lead to long-term, continuous-monitoring implantable sensors for high-performance athletes or high-risk patients.
Check Engine Light for the Human Body Could Improve Health Monitoring
According to a statement from the University of Tokyo and a Tokyo University-led team announcing the research, wearable health monitoring devices, including continuous blood glucose monitors, smartwatches, and aftermarket fitness trackers, are becoming a regular part of 21st-century life. Although they offer valuable information about some remotely measurable health signals, such as step counting or blood pressure monitoring, more complex analyses still rely on blood tests or other laboratory analyses.
Distinguished Professor Hiroyuki Fujita of Tokyo City University, who is also a professor Emeritus at the University of Tokyo, said these tests also face practical and analytical barriers that render the data they provide incomplete.
“Conventional approaches are often invasive or provide only snapshots in time,” Professor Fujita explained.
To expand the data and reduce the need for continuous lab tests, the researchers wanted to explore a device that would measure biomarkers, such as proteins indicating stress or possible disease, directly inside the body and export that data for external analysis, like a check engine light on an automobile.
“Our goal was to explore a biologically integrated system that enables continuous sensing and intuitive interpretation, even at home,” Fujita explained.
Engineered Cells Glow Green When They Sense Stress
Working with RIKEN and Canon Medical Systems Co., the research team explored the concept of an engineered skin that could sense data and communicate that data in the form of visible light. This search led Fujita and colleagues to epidermal stem cells, which they note, naturally maintain and renew the skin throughout its lifetime.
According to a study published in Nature Communications, the team genetically engineered a batch of these cells to respond to activation of the NF-κB pathway, which signals swelling. When swelling is detected, the new cells are programmed to express enhanced green fluorescent protein (EGFP).
After fashioning their engineered cells into an artificial skin, the researchers transplanted it onto lab mice. According to the team’s statement, the skin successfully “engrafted and functionally integrated” with the animal’s host tissue.
After the team induced inflammation, the grafted skin emitted a green fluorescence. In effect, the skin worked like a check engine light on a car to visually alert the operator of an out-of-range parameter, in this case, swelling.
When discussing the advantages of their implantable check engine light for the human body, the researchers noted that the sensor is composed of living cells, so it is naturally maintained by the human body. They also note that the cells’ bioluminescence is driven by their own internal mechanisms, eliminating the need for an external power source.
“Unlike conventional devices that require power sources or periodic replacement, this system is biologically maintained by the body itself,” Professor Shoji Takeuchi of the University of Tokyo explained.
For example, Professor Takeuchi noted that the sensor’s functionality “was preserved” for over 200 days in lab experiments, as the cells were continuously regenerated by the epidermis, just as the body’s own cells are.
From High-Performance Athletes to Livesrock Management
While the device is still in an early stage of trial and development, the researchers suggest their findings offer “a biologically grounded approach” for implanting living tissues designed to monitor health parameters, “blurring the boundary between biological systems and engineered devices.”
“The system leverages the body’s natural skin regeneration to support long-term biomarker monitoring, providing a visual readout without blood sampling after implantation and enabling intuitive assessment by observation,” they explained.
When discussing potential applications beyond sensing inflammation, the researchers said fields such as veterinary medicine and animal research could benefit from the ability to visually monitor individual parameters without invasive testing. These same benefits could apply to livestock maintenance or other applications where animals that cannot verbally communicate illness or disease
The researchers said their technology could be adapted to monitor human physiology beyond healthcare, including high-performance athletes who could benefit from an implantable check engine light for the human body.
“This study demonstrates a proof of concept for long-term, biologically integrated sensing without batteries, wiring, or active user operation,” they explained.
The study “Living sensor display implanted on skin for long-term biomarker monitoring” was published in Nature Communications.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.