The field of biosensors is a complex as well as young branch of research of the WG Sensorics at the IRS in cooperation with the WG Sensory Physiology of the Ruhr-University Bochum and the Department of Plant Biotechnology of the Institute of Biomaterials and Biomolecular Systems (IBBS) of the University of Stuttgart. Basically, the aim is to use insect odor receptors to develop technical sensor systems that, compared to conventional sensors for gases or specific molecules, open up a much broader spectrum of detectable substances and are more sensitive at the same time. Entitled "BIOSENSOR - Bio-sensors based on insect odor receptors", this project is funded by the Ministry of Science, Research and the Arts of the State of Baden-Württemberg. Due to the close cooperation with the partner departments, the respective expertise in the fields of cell physiology, biotechnology, etc. is combined with the long experience of the IRS in the field of sensor technology, providing a unique know-how. Due to the interdisciplinary nature of the research field, this is also necessary to achieve innovative solutions.

Applications and motivation

After millions of years of evolution, it is not surprising that the most sensitive detectors specialized for a wide variety of odors are found in nature. While mammals can detect different odors with their noses, insects "smell" with their antennae, on which there are thousands of sensilla necessary to detect odors. The population of different receptors is very large and includes between 500 and 1500 types in mammals and between 50 and 150 types in insects. At the same time, each receptor interacts only with certain molecules; in combination, this results in a tremendous coding capacity [1].

Accordingly, the potential range of applications for insect receptor-based sensors is broad. For example, wearable devices for autonomous monitoring of one's own health or for early detection of diseases based on respiratory gas analysis are conceivable. Furthermore, due to their biological nature, such sensors are ideally suited for quality assurance of food or water. They can also provide greater safety when monitoring indoor air or detecting dangerous or prohibited substances, such as explosives or drugs. Another application is in the entertainment industry, for example as a (thoroughly) useful gadget for the smartphone in the form of a mobile sniffer dog for various odors.

Transfer to space technology

Despite the research area seeming off-topic at first glance, biotechnological sensor concepts are also relevant to space technology. Because biomolecules function on a nanometer scale, probes could enable unprecedented miniaturization, which in space applications is equivalent to reducing weight and thus saving costs. However, the benefits are not only theoretical; practical applications can be defined for which miniaturized biosensors are important. One obvious application is in the field of life support systems, for example. Here, not only do various gases and gas mixtures need to be reliably monitored, but processes that are required for the production of vital substances, such as oxygen, also need to be controlled. One concept for this is based on algal bio-reactors, which allow production of O2 when supplied with light and CO2 [2].

Research areas and development

Due to the interdisciplinary nature of the research field, there are many topics relevant to biosensor development. While the Sensory Physiology WG in Bochum is concerned with the provision of the receptors, as well as the production of an artificial membrane as a carrier system, the focus of the Sensor Technology WG is on the technical application of these biological elements. The focus is on the development of a suitable transducer, i.e. a system that serves as an interface between biologically relevant signals and electrically measurable signals. Other tasks include the miniaturization of such sensors, the simulation of chemical or physical processes, and the development and application of suitable measurement technology.

Theses

Bachelor's or Master's theses are possible at any time and are usually posted on the IRS jobs page. In particular, theses on the following topics are possible:

• Transducers based on field-effect transistors (ISFETs)
• Numerical simulations in the area of convection-diffusion equations
• Development and characterization of subsystems
• Work on the self-developed inkjet printer for sensor production
  • GUI, programming
  • Electronic systems
  • Artificial intelligence (AI) for print improvement
• Biological topics in cooperation with biological partner institutes

Literature references

[1] Max-Planck-Gesellschaft: Geruchswahrnehmung bei Insekten; Forschungsbericht 2007 – Max-Planck-Institut für chemische Ökologie; https://www.mpg.de/424556/forschungsSchwerpunkt1

[2] Helisch, H.; Keppler, J.; Detrell, G.; Belz, S.; Ewald, R.; Fasoulas, S. and Heyer, A. G. (2020). High density long-term cultivation of Chlorella vulgaris SAG 211-12 in a novel microgravity-capable membrane raceway photobioreactor for future bioregenerative life support in SPACE, Life Sciences in Space Research 24: 91 – 107