TREND MEMS: The invisible doctors

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Tiny microelectromechanical systems (MEMS) have been used in countless electronic devices for a long time now. However, only now are they resulting in truly spectacular applications in the field of medical technology.

Electronic systems interact not only with humans or themselves – the environment too would like to “recognize” them. And devices with “MEMS inside” are amazingly good at this. These tiny microelectromechanical systems can be manufactured in large numbers and at low cost using established technologies from the field of semiconductors. This is certainly a reason why they are taking over large areas of our day-to-day lives. The acceleration sensors in our smartphones are just one example. They can also function as artificial ears, organs of balance or skin and can even detect smoke or toxins when used as noses or tongues. Anyone who produces useful things cheaply is sure to find a lot of buyers.

As a result, the MEMS market has been achieving double-digit growth for many years now. However, these days could now be numbered. IHS Markit expects growth of just 5 percent in 2017 compared to the previous year. Gyroscopes, magnetometers and the like have had their day. Between 2007 and 2013, they provided the biggest boost in MEMS’ 40-year history. However, smartphone sales are no longer rocketing with double-digit growth figures. And movement sensors are no longer cheap – they are now dirt cheap. This results in reduced turnover in spite of increasing production quantities.

Other sectors such as health care – one of the largest and fastest growing industries in the world – are stepping in instead. The increase in chronic illnesses, an aging population and at the same time growing health awareness are making medicine a highly lucrative area of activity. And MEMS are making it “personal” as they are helping to shrink medical technology to hand-held size.

The analysts at Stratistics MRC expect turnover achieved with MEMS in medical devices to increase from US$3.12 billion in 2015 to US$10.41 billion in 2022 – with a compound annual growth rate (CAGR) of 18.7 percent.

MEMS for medical technology

There is no lack of potential applications – they are as diverse as the health care sector itself.

  1. Pedometers
    Probably the simplest MEMS application in the medical field is the pedometer. Sensors record every motion three dimensionally (to the right, to the left and forwards) in order to distinguish steps from other movements. The data can then be used to determine the number of steps, distance, speed and calories.
  2. Hearing aids
    More and more manufacturers are relying on MEMS microphones. They are temperature-resistant, record high sound levels with good sound quality and suppress echoes. If a number of MEMS microphones are combined in a hearing aid, sound sources can be localized, thus improving spatial orientation for the wearer. While MEMS microphones achieved success on the market many years ago, most loudspeakers still function according to the principle patented by Werner von Siemens in 1877. In contrast, the MEMS loudspeaker presented by the Austrian start-up Usound and the Fraunhofer IDMT this year takes up half the space and uses a fifth of the energy of its “traditional” counterpart. It is due to be launched on the market in 2018.
  3. BioMEMS
    Diabetes patients still require a lancet and strip test in order to measure their blood sugar. In the future, implantable bio-sensors will do this for them. Researchers from the Institute for High Performance Microelectronics (IHP) have developed a bio-microelectromechanical system (BioMEMS) made from a conductive titanium nitride ceramic which is resistant to bodily fluids. There are now countless development projects for BioMEMS which can detect pathogens or administer drugs in a targeted manner. In the future, systems like these could be used to treat patients suffering from Parkinson’s disease with dopamine or apply anti-cancer drugs directly to tumor tissue.
  4. Glaucoma diagnostics
    A MEMS contact lens sensor continually measures glaucoma patients’ intraocular pressure on the basis of the curvature of the eyeball and transmits the measurements wirelessly. The Sensimed Triggerfish system is based on a contact lens with a tiny built-in strain gage. The wireless MEMS sensor comes from ST Microelectronics.
  5. Body gateway
    Medical platforms with MEMS sensors and actuators as key parts record not only movement data but also biological signals such as ECG or breathing rates and transmit them via Bluetooth to a smartphone for example which then transfers them to a health care server. In the process, sensor fusion procedures produce truly meaningful measurements. For example if the ECG and breathing measurements are to be combined with parallel movement patterns. Integrated into a plaster on a patient’s chest, sensor platforms like these can significantly reduce the amount of time people need to spend in hospital and can improve “long-distance relationships” with doctors.
  6. Lab on chip
    Shorter analysis times and lower sample material and chemicals consumption thanks to lab-on-a-chip technologies are revolutionizing laboratory work. And point of care diagnostics is given a new effective tool. The combination of microfluid, microelectronic and microoptical systems makes this possible. As part of the Sumcastec EU project, the Leibniz Institute for High Performance Microelectronics (IHP) is currently developing the world’s first lab-on-a-chip which will make it possible to detect and neutralize cancer stem cells more quickly. Micro channels, liquid memory, RF-MEMS broadband high frequency sources and detectors are integrated onto the silicon germanium (SiGe) chip. High-frequency electromagnetic radiation allows the inside of cells to be viewed without causing collateral damage.

The most exciting applications for MEMS technology nowadays are in the field of medical technology. However, this is only the beginning. In the future, tiny microelectromechanical systems will improve our quality of life not only when we are ill and will help doctors to diagnose diseases efficiently.



Sensimed Triggerfish (Image: Sensimed).

The Sensimed Triggerfish continually measures glaucoma patients’ intraocular pressure. (Image: Sensimed).