At the National University of Singapore (NUS), scientists have developed a novel aero-elastic pressure sensor called “eAir.”
Assoc Prof Benjamin Tee (center), together with Dr. Cheng Wen (left) and Ms. Wang Xinyu (right), have developed a novel aero-elastic pressure sensor called “eAir” (gold strips on the panel held by Assoc Prof Tee). This technology promises increased precision and reliability and can be applied to minimally-invasive surgeries and implantable sensors. Image Credit: National University of Singapore
This technology can be applied to minimally-invasive surgeries and implantable sensors as it is able to directly address the challenges associated with existing pressure sensors.
The eAir sensor promises increased precision and reliability across medical applications, and has the potential to transform laparoscopic surgeries by giving surgeons tactile feedback, enabling more accurate manipulation of patient tissues.
In addition, the sensor can greatly enhance patient experiences by giving patients a less invasive way of monitoring intracranial pressure (ICP), a key health metric for individuals with neurological conditions.
Headed by Associate Professor Benjamin Tee from the NUS College of Design and Engineering and NUS Institute for Health Innovation & Technology, the research team’s findings were recently reported in the scientific journal Nature Materials on August 17th, 2023.
From Lotus Leaf to Laboratory: Harnessing Nature’s Design
Traditional pressure sensors often struggle when it comes to precision. They struggle to deliver consistent readings, sometimes returning varying results when the same pressure is repeatedly applied, and can overlook subtle changes in pressure — all of which can lead to major inaccuracies and errors. These sensors also tend to be made from rigid and mechanically inflexible materials.
To help overcome some of these limitations, the NUS team gained inspiration from a phenomenon called the “lotus leaf effect” — a natural phenomenon where water droplets easily roll off the leaf’s surface, made feasible by its minuscule, water-repelling structures.
Imitating this effect, the research group has fabricated a pressure sensor with considerably enhanced sensing performance.
The sensor, akin to a miniature ‘capacity meter’, can detect minute pressure changes —mirroring the sensitivity of a lotus leaf to the extremely light touch of a water droplet.
Benjamin Tee, Associate Professor, Department of Materials Science and Engineering, National University of Singapore
Applying an innovative “air spring” design, the eAir sensor accommodates a trapped layer of air, thereby developing an air-liquid interface upon contact with the liquid of the sensor.
As external pressure increases, this air layer compresses. Applying a surface treatment enables the interface within the sensor to move without friction, causing a shift in electrical signals that precisely mirrors the applied pressure. Taking advantage of this design, the team has been able to reimagine the natural water-repelling capabilities of the lotus leaf in a simple yet elegant pressure-sensing tool.
The eAir devices could be made comparatively small — at a few millimeters in size — and this is equivalent to present pressure sensors.
Potential Game-Changing Advancement for Minimally Invasive Surgeries
The real-world applications of this technology are vast. For example, in laparoscopic surgeries where accurate tactile feedback is essential, integrating eAir sensors could result in safer surgical procedures, eventually improving patient prognosis and recovery.
Conducting surgeries with graspers presents its unique challenges. Precise control and accurate perception of the forces applied are critical, but traditional tools can sometimes fall short, making surgeons rely heavily on experience, and even intuition. The introduction of soft and readily integrable eAir sensors, however, could be a game-changer.
Benjamin Tee, Associate Professor, Department of Materials Science and Engineering, National University of Singapore
Leng stated, “When surgeons perform minimally-invasive surgery such as laparoscopic or robotic surgery, we can control the jaws of the graspers, but we are unable to feel what the end-effectors are grasping.”
“Hence, surgeons have to rely on our sense of sight and years of experience to make a judgement call about critical information that our sense of touch could otherwise provide,” explained Dr Kaan Hung Leng, Consultant, Department of General Surgery at the National University Hospital, Ng Teng Fong General Hospital and NUS Yong Loo Lin School of Medicine.
Dr Kaan, who is not involved in the research project, elaborated, “The haptic or tactile feedback provided by smart pressure sensors has the potential to revolutionize the field of minimally-invasive surgery. For example, information about whether a tissue that is being grasped is hard, firm or soft provides an additional and important source of information to aid surgeons in making prudent decisions during a surgery. Ultimately, these intra-operative benefits have the potential to translate into improved surgical and patient outcomes.”
eAir also presents a chance to enhance the process of monitoring intracranial pressure — the pressure inside the skull that has the potential to impact brain health. In the same way, by providing a minimally invasive solution, the technology could convert patient experiences in the management of brain-related conditions, that vary from severe headaches to possible brain damage.
Unfolding the Future of Smart Sensing
The NUS group is laying the groundwork for partnerships with key players in the medical field. They have also filed a patent for the eAir sensor technology in Singapore, and aim to interpret the technology for real-world applications.
We want to further refine the eAir sensor to enhance its performance by exploring various new materials and microstructural designs.
Benjamin Tee, Associate Professor, Department of Materials Science and Engineering, National University of Singapore
The team envisions the eAir technology being weaved into a diverse tapestry of applications for liquid environments.
Journal Reference:
Cheng, W., et al. (2023) Frictionless multiphasic interface for near-ideal aero-elastic pressure sensing. Nature Materials. doi.org/10.1038/s41563-023-01628-8.
Source: https://news.nus.edu.sg/