‘Biology meets microelectronics’ - a phrase often quoted in recent times, and one which underlines the increasing importance of inter- and trans-disciplinary research activities. Basic scientific disciplines such as physics, electrical engineering, chemistry, biology and materials science are increasingly seen to overlap common boundaries, so defining the interface of an exciting research environment with a high potential for innovation. In this context, the INB (Institute of Nano and Biotechnologies) at the Aachen University of Applied Sciences aims to combine synergistically its existing expertise in the fields of semiconductor technologies, nano-electronics, silicon-based chemical sensors and biosensors, DNA sensing and nanostructures along with biotechnology, plant and microbiology, bioprocess technology and mammalian cell cultures, enzyme technology and applied immunology. Seven research laboratories will focus their research activities on the pioneering spectrum of nano- and biotechnologies, a broad contemporary research area, fostering new ideas and the design of new products which may change our daily life. More details on the scientific orientation of this expertise within the institute and a description of the laboratories taking part in this work can be found below.
Silicon-based chemical sensors and biosensors, in terms of their micro- and nano-technological aspects, represent a challenging interdisciplinary area with a high potential for innovation. The importance of this topic is defined by the demand for miniaturization on the one hand, and the integration of sensors, actuators, and mechanical or fluidic elements onto one sensor chip and thus, the creation of miniaturized multifunctional analytical systems such as “lab-on-a-chip”, electronic tongue devices, µTAS (micro total analysis systems) or MEMS (micro-electro-mechanical system), on the other.To develop these sensor systems, a high standard of resources in both silicon- and thin-film processing is necessary, along with facilities to establish the characterization of micro- and nanostructures, especially at their interfaces and surfaces. In addition, tools for simulation and modeling in several dimensions are gaining importance in the development of micro- and nanosensors.
Besides fundamental research issues, chemo- and biosensorics together with chip technologies increasingly include application-oriented subjects. Here, the combination of micro- and nanostructures with stimulating functional materials offers a high potential for the development of intelligent sensor/actuator systems for numerous applications.
Research activities for medium- and long-term development include the following:
The laboratory for optical micro- and nanosystem technology combines different light-addressable technologies to create new types of sensors and actuators. On the sensor side, the main focus is on the light-addressable potentiometric sensor (LAPS), whereby changes in ion concentration and biomolecules could be determined on the sensor surface. Furthermore, light-responsive hydrogels are investigated, namely in terms of shrinking and swelling behavior. As a possible application this behaviour could be used in microfluidic channels as valves to control liquid flow streams.
Another field of interest is the light-addressability of living cells, using a light source to switch on or off certain metabolic pathways of cells. Also, light-addressable electrodes will be investigated to e.g., trigger catalytic processes in liquids such as the change of the pH value of the analyte.
Finally, the different areas of this research should be combined into a single system, comprising microfluidic channels, light-addressable cells and hydrogels as well as light-addressable electrodes and sensors. Such a system could be used to help current research investigations in medicine, pharmacy as well as basic research.
To support these set-ups, 3D-printing techniques are utilized to realize fast development and prototypes of new measurement set-ups, including microfluidics, configurations for measurement cells etc.
Surgery, radiotherapy and chemotherapy are the standard therapies for local tumor treatment and results commonly in a significant loss of quality of life and, moreover, in many cases effectiveness is limited. For example, in the case of prostate cancer, about one-third of patients will develop progressive or metastatic disease within 10 years after conventional treatment [Oefelein, M.G. et al., J Urol 158 (1997) 1460-1465]. In early metastatic disease androgen ablation is effective, but in most cases androgen-independent tumors develop. Subsequently, no effective treatment for androgen-independent prostate disease is available.
A promising possibility to render a therapeutic cancer treatment more effective could be the development of cancer-specific vaccines. The idea behind this approach is to activate the body's own defense system (especially, cytotoxic T lymphocytes) against cancer cells.
The activities of our laboratory “Applied Immunology” are focussing on the development and preclinical characterization of new therapeutic vaccines against cervical and prostate cancer.
Currently, the research is addressing on the following projects:
We develop and evaluate novel enzymes with the aim of direct technical application. One part of our approach is the efficient production of highly pure chiral compounds. Currently, the research is focused on the following topics:
Diacetyl and acetoin exhibit a butter-like flavor in alcoholic beverages, like beer and wine. These compounds are undesired in beers to give a clean, crisp taste, whereas higher concentrations of these compounds are desired in wines for a smoother taste and feel. Different novel acetoin reductases are recombinantly produced and investigated for the quantitative determination of diacetyl and acetoin in microbial fermentations.
Vicinal diketones, like diacetyl, are not only naturally produced in fermentation processes but can also yield chiral α-hydroxy ketones and vicinal diols by stepwise reduction. These are interesting synthons for complex chiral structures or monomers for mixed polymers with unique properties, respectively. As the chemical synthesis of enantiomerically pure α-hydroxy ketones or vicinal diols is difficult to achieve the direct, biocatalytic conversion of vicinal diketones with enzymes is advisable. Selected acetoin reductases/butanediol dehydrogenases are developed to achieve that aim.
Subtilisin protases are widely used in different industries, e.g. as an active component in laundry detergents. In this work, we aim to find even more suitable novel enzymes by cloning of new genes with relatively low homology to already known subtilisin genes and evaluation of the biochemical and performance parameters of the subsequent enzymes.
Over the past few years, the significance of Cell Culture Technology has increased considerably. It has become a key technology for the production of therapeutical proteins using biotechnology. Only mammalian cells can synthesize complex glycosylated proteins in an efficient manner. The expression of such proteins is industrially performed using recombinant hamster cells (CHO) or mouse cells (hybridomacells). For large-scale fermentation, suspension cultures in stirred tank fermenters are used in a scale up to 100 m3. The most relevant process technology is the fed-batch culture, using controlled feeding of the culture with media concentrates to prevent nutrient limitations.
Recent methods for process optimization are aimed at reducing the time of process development. For this purpose, fermentation data must be obtained even in the early stages of fermentation under controlled and reproducible conditions in order to allow a scale up of the process later on.
According to this, the research and development activities of the “Laboratory for Cell Culture Technology” are application-oriented and aimed at the development of:
Biosensorics is one of the most exciting and multidisciplinary areas of research and effectively interfaces with material science, device physics, micro/nanotechnology, biochemistry and life sciences. Coupling the unique recognition and signal-amplification abilities of biomolecules and living biological systems, that have been developed and optimized during millions of years of evolution, with artificially man-made Si chips is one of the most attractive and promising approaches for a new generation of (bio-)chemical sensors and biochips. Moreover, the rapid development of nanotechnology opens new and encouraging possibilities to create a new class of nano-scaled chemical sensors and biosensors by using new physico-chemical phenomena occuring in the nano-world. The potential application of these devices reaches from medicine, biotechnology and environmental monitoring over food and drug industries up to defence and security purposes including antibioterrorism and biological warfare agents field.
The main research activities of the laboratory of DNA sensors and nanostructures are focusing on:
Development of new (bio-)chemical micro/nanosensors and multi-parameter sensor systems via an integration of functional and stimuli-responsive materials (ferroelectrics, hydrogels, degradable polymers), nanoobjects (carbon nanotubes, gold nanoparticles) and charged macromolecules (polyelectrolytes, tabacco mosaic virusdendrimers, enzymes, DNA, proteins) with semiconductor field-effect devices and Si chips. Examples are label-free DNA sensors, biomolecular logic gates and bio/nano-hybrids or the TMV nanocarrier.
Theoretical modelling of field-effect devices modified with charged macromolecules.
Nanostructuring via conventional photolithography and pattern-size reduction technique.
In the last two decades, microbiology has undergone a paradigm shift. Where previously only small numbers of cultivable microorganisms were tested out for their biochemical characteristics, the metabolic properties of entire microbial communities are now available from increasing numbers of (meta) genome projects. The wealth of genetic information is, however, in parts still not understood. Recombinant enzyme technology provides rapidly multiple variants of known enzymes by functional expression of orthologous genes and is a powerful tool for functional studies of proteins of previously unknown function.
Using an in-house developed, sophisticated vector-based cloning system dedicated for applications in synthetic biology, a variety of enzymes from origins orthologous and paralogue origin to known sources are produced and studied in order to establish their properties . In particular; complex enzymes composed of multiple subunits and/or complex maturation requirements became only recently accessible for efficient recombinant production in heterologous hosts . Likewise, the cloning system has been used in order to provide single metabolic pathway modules [1, 2], which are now combined in order to create tailor-made microbes which exhibit physiological and metabolic features that are not found in nature.
Against the background of the progressive scarcity of fossil fuels and global warming by the release of carbon dioxide as a result of their immoderate exploitation, new ways of regenerative use of raw materials and energy are required. The provision of renewable raw materials exclusively from agriculture or the alternative cultivation of marine algae cannot solve the problem, since the area required for phototrophic production of biomass is much too large to simultaneously permit feeding a growing world population . An alternative for regenerative supply of chemical raw materials and energy substrates is provided by diverse metabolic activities of chemolithoautotrophic microorganisms. In particular, the principles of hydrogenotrophic life can offer attractive alternatives for modern biotechnology. A very productive link between renewable energy, hydrogen based biotechnology and storage of temporary surplus of electric power for sustainable, biotechnical production of raw materials for the chemical industry might become accessible using these principles. Metabolic activities described recently in chemolithotrophic microorganisms open a wide field for a tailor-made synthetic biologic development of organisms for the production of interesting starting materials on an industrial scale [4, 5].
Actual scientific projects are:
1. Development of a mobile monitor for the assessment of biogas processes
(in cooperation with M.J. Schöning)
Despite its growing importance as a supplier of renewable energy the biogas process is still poorly understood. The development of mobile sensors for use in the field is therefore an important prerequisite for continuous monitoring and stability control of smaller plants. In this project, sensor chips are to be modified with suitable microorganisms and enzymes in order to allow important conclusions regarding effectiveness and stability of the biogas process with little efforts.
2. Development of a sensor for the determination of acetoin (in cooperation with P. Siegert, J. Bongaerts und M.J. Schöning)
Acetoin (3-hydroxybutan-2-on) is a metabolite of microorganisms, which is in particular formed with good nutrients supply under anaerobic conditions. While the substance is considered off-flavor in the production of beer or wine in higher concentrations, low concentrations are tasty forming. Likewise, low acetoin concentrations acts as flavoring additives in nutrients. Acetoin reductases from various sources are recombinant produced and tested to be used for the quantitative determination of acetoin in microbial fermentations using appropriately modified microchips.
3. Transmission of autotrophic metabolic capabilities on the heterotrophic intestinal bacterium Escherichia coli (in cooperation J. Schiffels)
In this project, the influence of the recombinant production of functional hydrogenases on the redox balance of Escherichia coli strains is examined. In particular, the influence of hydrogen on the production of various industrially interesting basic chemicals (solvents and polymer building blocks) is investigated. For this purpose, individual metabolic modules are housed in suitable vectors and then combined in E. coli in order to detect effects on product yields caused by the hydrogenases quantitatively.
4. ACidestion: Modified VFA (fatty acid) - silage for controlling a needs-based biogas production (in cooperation with I. Kuperjans (Nowum Energy Institute))
The aim of this project is the development of alternative ensiling strategies that lead to a higher fatty acid content of silage for a short term, demand-dependent increase of biogas yields. Based on this approach a deliberate balancing of temporary failures of other renewable energy sources (wind and solar) might be possible.
1. Aboulnaga el, H., et al., Effect of an oxygen-tolerant bifurcating butyryl coenzyme A dehydrogenase/electron-transferring flavoprotein complex from Clostridium difficile on butyrate production in Escherichia coli. J Bacteriol, 2013. 195(16): p. 3704-13.
2. Schiffels, J., et al., An innovative cloning platform enables large-scale production and maturation of an oxygen-tolerant [NiFe]-hydrogenase from Cupriavidus necator in Escherichia coli. PLoS One, 2013. 8(7): p. e68812.
3. Bioenergie: Möglichkeiten und Grenzen, B. Friedrich, B. Schink, and R.K. Thauer, Editors. 2013, Deutsche Akademie der Naturforscher Leopoldina Nationale Akademie der Wissenschaften.
4. Hugler, M., et al., Autotrophic CO2 fixation pathways in archaea (Crenarchaeota). Arch Microbiol, 2003. 179(3): p. 160-73.
5. Fuchs, G., Alternative pathways of carbon dioxide fixation: insights into the early evolution of life? Annu Rev Microbiol, 2011. 65: p. 631-58.
Microorganisms, such as bacteria, archaea and fungi, are divers and exhibit remarkable metabolic variability. This makes microorganisms even more interesting as production organisms for valuable products. Since renewable raw materials are converted, they will make a decisive contribution to a sustainable economy, also referred to as bioeconomy. Industrial microbiology deals with the identification, evaluation, improvement and utilization of microorganisms in order to produce a wide range of products, including foods, beverages, platform chemicals, fuels, pharmaceuticals and enzymes. Bacillus species, mainly B. subtilis, B. licheniformis and B. amyloliquefaciens, are well-established production hosts for important technical enzymes on a very large scale. Nevertheless, it is important to identify and develop new production hosts to improve the availability of industrial enzymes, both novel and existent, in competitive yields and to open the process for new potential. On the other hand, genetic accessibility of already established production strains is often very limited. This leads to the need for better tools, in particular when the aim is to engineer the genome.
Currently, the research is focused on the following projects:
The field of semiconductor technology will in the future be increasingly dominated by nano-electronic structures due to progressive miniaturization. Modern information technology systems are based on extremely thin layers of materials and small structures just nanometers in size, where quantum-physical effects are used specifically to develop devices in an efficient way. With an atomic layer resolution, the semiconductor epitaxy is the key technology in the production of optoelectronic as well as nano-electronic structures. Examples of this are "Quantum Cascade Lasers", "Single Electron Devices ", "High Electron Mobility Transistors (HEMT)" and "Semiconductor Lasers", besides many other quantum devices.
Small structures or extremely thin layers will continue to increase in significance in the field of high-frequency engineering. As an example, "hot electrons" are used in III/V-heterostructure devices for the production of microwaves in the automotive industry; at present, quantum physical structures for "quantum computing" are being applied in the area of information technology. Moreover, quantum devices could play an important role in the future production of high frequencies in the THz area.
Future research in this field will undoubtedly include a clear application component besides pure fundamental research. In close cooperation with the Research Center Jülich, micro-and nano-electronic structures and systems will be produced and the qualities and prospects for future semiconductor devices are under examination. The following areas are of specific interest:
Development of micro-and nano-electronic semiconductor structures as well as electronic, quantum physical and high-frequency construction elements.
Further development of structuring methods in the micro- and nanometer area as well as the development of device processing as well as of micro-and nano-electronic structures for sensor applications.