A research team at Hong Kong Polytechnic University has developed optical fibre sensors used in railway safety monitoring technologies for health monitoring.


In a statement, PolyU described the novel Side Hole Polymer Optical Fibre Sensors as "biocompatible, supple and extremely sensitive to very small pressure changes inside the human body".

Professor Hwa-yaw Tam, lead researcher and head of the university's Department of Electrical Engineering, said the sensors can detect "extremely subtle changes even of a difference smaller than 1% of atmospheric pressure – sensitive enough to measure the pressure inside the lungs while breathing, which changes by just a few kilopascals".

Adding a side hole running in parallel with the light transmission path inside the optical fibre helped increase sensitivity.

Also, the novel sensors break past the limitations of traditional optical fibres that are based on glass or plastic materials as these are made with an advanced plastic material known as ZEONEX, which has low water absorption and high heat resistance.

Findings on the development of the new optical fibre sensors were published in the journal Optics Letters of The Optical Society.


PolyU's newly-developed fibre sensors may be utilised in various medical applications from improving surgery precision to providing new ways of monitoring human body recovery from the inside. The university offered examples including smart cochlear implantation, bone fracture recovery monitoring and navigation monitoring in cardiac catheterisation.

The optical fibres can also act as sensors to detect external changes by observing light beam reflections. The use of fibre optics technology has also been seen in surgical instrumentation, diagnostic and imaging equipment or sensor-based wearable medical devices.

Prof. Tam's research team is seeking to explore more medical monitoring applications of the novel sensors, including their use for precise navigation and shape detection in cardiac catheterisation. They are also keen to expand the sensors' ability to measure other physical or chemical changes like acidity and temperature.

Additionally, the team is looking at integrating the sensors with emerging tech like wireless IoT. "The sensing network would be able to give a comprehensive and precise picture of changes inside the human body, thus helping patients around the world via technological innovation," Prof. Tam said.


The PolyU research team has joined hands with their counterparts from Australian and Japanese universities to develop various sensors for medical monitoring. One use case is in a smart cochlear implant that could provide critical information about location and force to surgeons in real-time during the implantation procedure. In-vitro testing of the device will be done at the University of Melbourne and the Royal Victorian Eye and Ear Hospital.

The team has also been working with researchers from Monash University in Melbourne to combine its fibre sensors in orthopaedic implants for monitoring bone fracture recovery.

In other health monitoring-related news from the Asia-Pacific region, a recent study by Samsung researchers showcased a new skin patch that combined a photoplethysmography sensor with a stretchable organic LED display to measure and display a user's heart rate in real-time.


"The new plastic sensors are humidity insensitive, supple and shatter-resistant. They are also chemically inert, biocompatible, and can be made super tiny in size. These unique features make the sensors ideal for integration with medical implants," Prof. Tam said.