Innovative Sensor Solutions

© Fraunhofer EMFT/Bernd Müller

Sensor materials for combined in-line measurements

As the »sensory organs of things« sensors have a key role to play in future applications in the area of the Internet of Things (IoT). However, this involves rigorous requirements in terms of performance and robustness as well as the energy and cost efficiency of these miniature electronic aids. 

One particular challenge lies in adapting chemical or biological sensors specifically to IoT applications. Fraunhofer EMFT has years of experience in the development of sensor system technologies which can especially be put to wide-ranging use in chemosensorics and biosensorics. One key component in terms of creating a stable and valid sensor system is the necessary system technology. Model-supported signal analysis, nonstationary measurement methods, multi-variant sensorics and modern methods of numerical signal processing provide the basis here.

The EMFT competence innovative sensor solutions is subdivided into the following subthemes: IoT sensor systems, sensor systems on flexible substrates, flow sensors, chemical sensorics, biosensorics and cell-based sensorics.

Brief Description of the Subthemes:

IoT sensor systems

IoT sensor systems have to be able to run on very little energy or even be self-sufficient. Near-Field Communication (NFC) and low-power electronics are examples of technologies used for this purpose in IoT sensor nodes developed at Fraunhofer EMFT. BLE (Bluetooth Low Energy) technology can be used to interconnect these IoT sensor nodes, also enabling larger distances to be overcome.

Sensor systems on flexible substrates

Meanwhile, sensor systems on flexible substrates enable an extremely low installation height, a high degree of flexibility, robustness and relatively low manufacturing costs, especially when produced in large quantities. The open form factor also allows integration in and on various surfaces. Fraunhofer EMFT has longstanding expertise and the necessary infrastructure to be able to produce such electronic systems efficiently and cost-effectively on foil using roll-to-roll methods.

Flow sensors

There are already sophisticated solutions available to measure most physical parameters; here, markets can only be penetrated by means of novel concepts. One example is flow sensors for the dosage of minute amounts of liquids and gases within the nanoliter range. Various technological approaches are pursued in this area:

  • One module for the dosage of tiny liquid volumes is based on capacitive sensorics (using the kind of chips which are also used in mobile phones). Fraunhofer EMFT researchers have developed a dosage module that is able to dispense tiny volumes of lubrication oil in a range of 2-30 nanoliters/minute on a closed loop basis in the bearings of machine tool spindles.
  • One variant of this capacitive concept was developed in order to precisely measure and dispense very small volume packages (12 µl) of a highly effective cancer medication. This technology also has the potential to be used in future patch pumps.
  • Another innovative dosage chip developed at Fraunhofer EMFT is based on the pressure difference principle. Samples of this dosage chip were produced at an industrial MEMS fab and used in range of different medtech industrial projects. This dosage chip also has the potential to be deployed very cost-effectively in disposable medical products.
Chemical sensorics

There is a need for somewhat more basic research in the field of chemical sensorics in general and the area of gas sensorics in particular. Gases and fluids can be analyzed very precisely by determining their physical properties, but the measuring systems used tend to be excessively large and expensive. What is more, the chemical sensors currently available often only provide stable and reliable measurements to a limited degree. Over time they lose their sensitivity and have to be re-calibrated, and they can also be subject to crosssensitivities which distort measuring results. For this reason, Fraunhofer EMFT researchers are working on new optical, impedimetric and potentiometric sensors in order to achieve long-term stability and selective/sensitive measurements of chemical parameters in gases and liquids. The institution has special measuring stations as well as the experience in measurement technology that is required here. What is more, individually tailored biochemical and chemical sensor materials and sensor concepts are developed at the institution for the purpose of analyte detection and the associated optical/ electrical signaling.

Biosensorics

Biosensorics poses an even greater challenge due to the complexity of the molecules. Innovative sensor materials are used at Fraunhofer EMFT to develop novel methods and techniques for detecting microorganisms, for example. Measurement systems based on such sensor materials can be constructed on an energy-efficient basis to ensure the technology is suitable for portable hand-held devices for use in such areas as medical technology and environmental analytics.

Cell-based sensorics

Meanwhile, cell-based sensorics makes use of microelectronic systems to measure the response of living cells to various environmental factors and analytes. This kind of biotechnological hybrid can be used to measure and analyze the toxicity of chemicals, the effects of medication, environmental influences and even complex interactions with a high sample throughput. Potential applications extend to the most innovative branches of personalized, regenerative medicine. Foil-based lab-on-chip systems enable fast, low-cost point-of-care diagnosis of various illnesses.