From bench to bedside: Europe’s medical sensor revolution
Companies across Europe are developing the next generation of medical sensor technology, from infection testing to heart monitoring and even DNA analysis. However, there are significant challenges in bringing these technologies to end users.
Technologies from graphene and edge emitting laser diodes to magnetic sensors and micromachined ultrasonic transducers are providing system designers with new options for medical equipment.
One of those is UK graphene specialist Paragraf. It is working with Tachmed in Surrey, UK, on a scalable, cost-effective, and accurate diagnostic testing to homes and primary care clinics using its transistor technology. In the system, Paragraf’s proprietary graphene field-effect transistor (GFET) is used as a sensor (above) that tests for various conditions, including COVID-19 and influenza.
The TachShield cloud system combines rapid diagnostic tests, connected devices, software, and APIs through a single mobile app. Tachmed works with Amazon Web Services and AI firm Anthropic on the technology to analyse the test results, and has raised $10 million in seed funding. It is now in its Series A funding round.
The graphene-based diagnostics device is designed to serve as the central point for aggregating information about an individual’s health. Machine learning and artificial intelligence automatically process and securely share the data with doctors and other relevant parties.
The AI makes decisions based on the data, determining the necessary behavioural changes or therapeutic interventions to enhance the individual’s health. In the event that a prescription is required, the process can be automated, or a follow-up appointment with a physician can be scheduled.
“This partnership marks a major milestone in Tachmed’s journey to transform access to precise, real-time health diagnostics,” said Paul Christie, Founder and CEO of Tachmed. “We’ve already demonstrated the potential of TachShield, and now, in working closely with Paragraf, we have the opportunity to scale that impact exponentially. We aren’t just advancing diagnostics, we’re helping to build a future where early detection can become a reality for everyone, everywhere.”
The devices will be built at Paragraf’s graphene foundry in Huntingdon, Cambridgeshire, for high volume production. “This collaboration with Tachmed allows us to apply our cutting-edge GFET technology where it can make the most immediate human impact,” said Simon Thomas, CEO of Paragraf. “By enabling precision diagnostics in everyday settings, we can truly reshape how people engage with their health.”
LED sensing
The increasing performance and lower cost of LED is also driving medical sensor systems that are sensitive enough for DNA analysis.
The latest cyan-coloured edge emitting laser (EEL) diode from ams Osram in Austria is up to five times brighter than its predecessors at 300mW. The LED is designed specifically for life science applications, it emits at a wavelength of 488nm ±2nm to stimulate the fluorescent dyes used for analysis of blood, serum, and plasma analyses, as well as DNA sequencing.
This method for diagnosing genetic conditions involves directing light through a biological sample. Nucleotides, as the building blocks of DNA, can absorb and emit light in a distinct way, allowing their sequence to be accurately determined. A more powerful laser diode enables faster and more accurate analytical results.
A high modulation bandwidth of 100MHz allows for the precise control of light intensity, significantly boosting both signal quality and the speed of analytical processes.
The higher performance of the PLT5 488HB_EP (right) allows faster, more accurate analysis, increasing diagnostic possibilities in large-scale laboratories. It also paves the way for more compact and cost-efficient diagnostic systems tailored for healthcare facilities, hospitals, and nursing homes.
“Our 488nm laser diode delivers exceptional optical performance, ensuring reliable analysis while reducing power consumption. It is thus the perfect choice for precision-critical applications—whether in laboratories, hospital settings, or forensic facilities. This diode stands out due to its low noise, broad modulation bandwidth, and top-notch beam quality”, emphasizes Winfried Schwedler, Marketing Manager at ams OSRAM.
Thermal management is also key for integrating these LED sensors into a system. The diode has low thermal resistance to enable reliable operation even at high temperatures of up to 60 °C. An integrated photodiode for output control and an ESD protection diode also boost the robustness and reliability of the diode.
Researchers in Switzerland have used quantum techniques to create a self-illuminating chip-scale medical sensor.
The team at the Bionanophotonic Systems Laboratory in the School of Engineering at EPFL in Zurich used quantum tunnelling across a barrier of aluminium oxide to emit photons. A metasurface sensor then collects the light passing through a sample.
“Tests showed that our self-illuminating biosensor can detect amino acids and polymers at picogram concentrations – that’s one-trillionth of a gram – rivaling the most advanced sensors available today,” says Bionanophotonic Systems Laboratory head Hatice Altug.
Metasurface
At the heart of the sensor is a metasurface to control the resulting light emission. This is built from a mesh of gold nanowires which act as nanoantennas to concentrate the light at the nanometer volumes required to detect biomolecules efficiently.
“Inelastic electron tunneling is a very low-probability process, but if you have a low-probability process occurring uniformly over a very large area, you can still collect enough photons. This is where we have focused our optimization, and it turns out to be a very promising new strategy for biosensing,” says former Bionanophotonic Systems Lab researcher Jihye Lee who is now an engineer at Samsung Electronics.
The quantum platform is built at EPFL’s Center of MicroNanoTechnology and is compatible with sensor manufacturing methods. Less than a square millimeter of active area is required for sensing, making it suitable for handheld biosensors.
“Our work delivers a fully integrated sensor that combines light generation and detection on a single chip. This can be used for applications ranging from point-of-care diagnostics to detecting environmental contaminants,” says lab researcher Ivan Sinev.
Ultrasound sensing
Infineon Technologies in Germany has also made significant progress in developing its capacitive micromechanical ultrasonic transducers (CMUT) technology. Earlier this year it showed the first integrated one-chip implementation of the MEMS-based ultrasonic transducer with a smaller footprint, improved performance, and higher functionality that a discrete piezoelectric transducer. This integration opens up new ultrasonic medical sensor applications.
“Our ultrasonic technology can achieve a very high signal-to-noise ratio and offers a high level of integration. That’s why we believe that the devices represent a breakthrough in the industry,” says Emanuele Bodini, Senior Director at Infineon. “We want to leverage the technology to develop a product platform that is capable of serving multiple use-cases through different industries.”
Unlike conventional piezoelectric bulk materials, which rely on the deformation of the material itself, CMUT transmit and detect ultrasonic waves via the deflection of a micro-machined, semiconductor diaphragm.
In the transmitting state, a DC bias is applied between the upper and lower electrode plates of the CMUT. Through the superposition of AC voltage and DC bias voltage, the film produces simple harmonic vibration along with the AC signal, converting electrical energy into mechanical energy and generating ultrasonic waves.
In the receiving state, a DC bias is applied between the upper and lower electrode plates. The vibrating film vibrates under the sound pressure of the ultrasonic wave, causing a change in the capacitance value. The ultrasonic wave is detected by detecting the change in capacitance, thereby realizing the conversion of mechanical energy into electrical energy.
The technology has not yet reached the product stage, but Infineon says compared to a discrete design the monolithic integration of MEMS and ASIC reduces the noise floor by 20 times and improve the absolute signal by 1000 times compared to conventional piezoelectric ceramics of a similar size.
The CMUT technology can be used to develop devices for vital signs monitoring, health tracking, and non-invasive medical diagnostics. The CMUT sensor provides continuous monitoring and feedback rather than a single measurement to detect potential health issues earlier and improve patient outcome.
Solid-state buttons
The ultrasound sensor can also be used for solid-state touch buttons under any solid material, such as glass and even metal, without deforming the surface. This allows a more durable and reliable alternative to conventional mechanical buttons to be implemented, reducing the risk of wear and tear, and increasing the hygiene and overall lifespan of devices.
Compared to capacitive touch buttons, which can be impacted by environmental factors such as humidity and temperature, CMUT-based touch buttons are resistant to water and have high EMC robustness. As the technology reduces the size of the buttons, they can be integrated into various devices, such as touch buttons below the metal frame of a mobile phone or replacing car door handles for a neat design.
Magnetic sensing
Up in Scotland, the University of Glasgow has opened a magnetics research lab for medical sensor development.
The lab has a magnetically shielded room to eliminate magnetic interference from external sources, such as nearby electronics and the Earth’s magnetic field. This will help researchers develop prototypes of the next generation devices for detecting the extremely weak biomagnetic signals produced by human muscles (magnetomyography or MMG) and organs such as the heart (magnetocardiography or MCG) and brain (magnetoencephalography or MEG).
Neuranics, a spin out of the universities of both Glasgow and Edinburgh, is using the lab to test its developing spintronics-based medical sensors for health, fitness, and extended reality (XR) applications.
“The potential applications are incredibly exciting, especially in medical diagnostics. Three-dimensional measurements of magnetic signals could help identify conditions that traditional methods might overlook, such as certain types of ‘silent’ strokes,” said Professor Hadi Heidari, from the James Watt School of Engineering and Chief Technology Officer (CTO) of Neuranics, who also led the installation of the magnetism lab.
“The magnetism lab will help us make MMG sensors sensitive enough for sophisticated measurements of the human body, which could be integrated into everyday life. That might mean a credit card-sized device that monitors your heart for 24 hours or a wristband that allows precise control of prosthetic limbs.”
Neuranics is also leading a project to develop a local fabrication and advanced packaging supply chain for the sensors. It is working with Kelvin Nanotechnology (KNT) and the University of Glasgow on a state-of-the-art nanofabrication centre, enabling full fabrication of magnetic sensors in the UK, reducing reliance on overseas facilities and strengthening domestic supply chains.
This will be the first plant in the UK dedicated to full end-to-end magnetic sensor fabrication and assembly, with one of only two Ion Beam Etch systems in the UK.
DNAnudge
But rolling out the technology can be a struggle.
Only last year in August, UK start up DnaNudge was rolling out 20 minute DNA tests in health food stores. This built on a ‘lab-in-a-cartridge’ sensor system that was developed with TTP in Cambridge and came to the fore during the Covid-19 pandemic. This is now providing data on how quickly an individual can clear caffeine from their system (whether a ‘fast’ or ‘slow’ caffeine metaboliser), as well as the impact of oxidative stress on their skin.
The company was founded in 2015 by Professor Chris Toumazou of Imperial College London who had previously founded Toumaz Technology to develop ultralow power wireless sensing in bandages.
“Having introduced the first on-the-spot consumer genetics services in a retail setting anywhere in the world, we have now innovated one step further with this industry-first Express DNA Test,” said Toumazou. “With this new superfast in-store test, we are making it even easier for consumers to make the right food and skincare decisions for their unique genetics, empowering people with new levels of knowledge to positively impact and proactively improve their health and wellbeing.”
However this all fell apart later in the year when the company fell out with backer Ventura Capital and entered administration.
Future sensors
Nevertheless, Europe is at the forefront of developing leading edge medical sensor technologies. This is highlighted by the deal signed by Belgian research group imec in Belgium with several labs in the US. The deal with the Massachusetts Institute of Technology (MIT) will see the labs develop the next generation of AI-enabled nanoelectronic sensors for monitoring biomarkers and vital signs in clinical, point-of-care, or home settings.
“We believe that by integrating cutting-edge semiconductor technology and AI, our collaboration with MIT has the ability to revolutionize healthcare,” said Veerle Reumers, head of health strategy & portfolio at imec USA. “With MIT’s healthcare and microsystems expertise, and imec transferring novel technologies to industry, this combines decades of complementary experience.”
European expertise in analog and sensing technology has been key to the development of new types of medical sensor. This is opening up opportunities for new types of monitoring equipment, from wearables to the bedside, with smaller size and higher performance.
www.paragraf.com; www.imec-int.com; www.st.com www.ams-osram.com; www.infineon.com; www.neuranics.com; www.epfl.ch
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