Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Fitting pieces for biosensors - New book provides an overview of aptamer development and applications

Research and industry are increasingly exploiting the potential of aptamers. As well as their application in research, medical diagnosis and treatment, aptamers are also interesting as a basis for biosensors for use in environmental analysis because their characteristics enable them to identify and bind target molecules as surely as a key fits a lock. In a new book, researchers at the Helmholtz Centre for Environmental Research (UFZ) describe the methods used to obtain aptamers. A newly-approved project aims to develop new nanostructured biosensors to measure harmful substances in water.

The term aptamer means something like "fitting pieces" (from the Latin word aptus, meaning to fit, and the Greek word meros, meaning piece). Aptamers consist of nucleic acids and have a three-dimensional structure that enables them to identify and bind certain target molecules.

These binding abilities allow, for instance, tracing, detecting and measuring certain substances. For this purpose aptamers can be used in e.g. biosensors. Biosensors are a simple, quick, low-cost way of taking measurements. At the heart of all biosensors there is a biologically active component.

This bioreceptor has the ability to interact with its target substance, producing a signal in the process. Signal transducers in the sensor make the signal measurable and visible. Once measurement has taken place, the biosensor is returned to its original state. In other words, it can be regenerated.

To design biosensors, scientists need suitable bioreceptors that can identify the target substance. Aptamers offer great potential for use as biological recognition elements in biosensors. Firstly, however, the scientists have to identify the right aptamer for a particular target molecule. Such target molecules can be very complex structures, like whole cells or organisms, or tiny molecules consisting of just a few atoms. The search for the right aptamers is like managing a gigantic molecular dating agency. Using an in vitro method, researchers select the best binding partners for the target molecule from a huge pool of 1015 (10 million x 100 million) nucleic acids with different sequences. This selection method is called SELEX (Systematic Evolution of Ligands by EXponential enrichment). SELEX is an evolutionary process performed in a 'test tube' (in vitro). Therefore the use of animals, plants or cell cultures is not required during the process. Beside ethical benefits, another advantage of this is the possibility of aptamer selection even for toxic substances.

Once suitable binders (aptamers) for a target molecule have been found by the SELEX process and their sequences have been defined, aptamers can be produced very accurately and reliably at any time by chemical synthesis. Accordingly no biologically induced variations have to be taken into account during synthesis, as they would if natural systems were used. Another advantage is the possibility to give the aptamers defined properties relatively easily by sequence modifications or by adding functional groups or reporter molecules. The added properties can enable or simplify the measuring process, or improve the stability of the aptamers.

In the UFZ's biosensor laboratory headed by Dr Beate Strehlitz, Dr Regina Stoltenburg has developed two different modifications of the SELEX method. One of these is known as FluMag SELEX. The 'Flu' stands for fluorescence and refers to the fact that a fluorescence molecule is added to the nucleic acids during the SELEX procedure to make them visible. In this manner the molecules can always be found again and researchers can measure the enrichment of those which exhibit best binding and detecting abilities to the given target. The 'Mag' refers to magnetic beads.

These are dust-mote-sized magnetic beads onto which the scientists 'stick' the even smaller target molecules to make them more manageable. Many other modifications of the SELEX procedure have been developed by teams in research institutes around the world enabling aptamer selections for a wide range of different applications. In the new book "Aptamers in Bioanalysis" (M.

Mascini, Wiley-Interscience) Beate Strehlitz and Regina Stoltenburg describe the SELEX procedure and its many variants in a review chapter.

By use of the FluMag SELEX procedure, developed by the UFZ research group in Leipzig, aptamers for a wide range of target molecules can be selected. Thus it has been used successfully to generate aptamers for a protein, a peptide and for ethanolamine, the smallest molecular aptamer target so far. The ethanolamine-binding aptamers have been patented. Additionally Dr Christine Reinemann succeeded in selecting aptamers for soluble constituents of Penicillium expansum spores (mould spore extract). Based on this aptamers she hopes to develop a detection method for mould fungi within a project with third-party funding from Saxony’s Office for Environment, Agriculture and Geology (LfULG). Mould fungi are one of the reasons behind the increase in allergies in Germany. Together with PhD student Sören Linkorn and researchers from the Institute of Food Technology and Bioprocess Engineering at TU Dresden, Dr Regina Stoltenburg wants to select aptamers that can recognise pathogenic bacteria. These aptamers are supposed to develop a biosensor-based detection method for pathogens in water. This research is being conducted within the International Water Research Alliance Saxony (IWAS). A quick method for identifying these harmful germs is particularly important in arid parts of the world because contaminated drinking water in these areas can cause diseases, death and even epidemics.

The German Federal Ministry of Education and Research (BMBF) has just approved a joint project under leadership of Forschungszentrum Dresden-Rossendorf (FZD) and in collaboration with the University of Rostock, proaqua GmbH & Co. KG in Mainz and the UFZ. The project is part of the BIONA (Bionic Innovations for Sustainable Products and Technologies) research programme. It will use the natural nanostructures of bacterial coat proteins to fix aptamers onto sensor surfaces in a controlled manner. The UFZ is to develop aptamers that are capable of detecting certain organic substances, such as undesirable pharmaceutical residues, that enter the environment through wastewater.

If the UFZ researchers are successful, in a few years' time, biosensors will be able to help with the prompt identification of potential health risks, such as mould fungi in rooms or germs and pharmaceutical residues in water.

More Information:
Dr Beate Strehlitz
Helmholtz Centre for Environmental Research (UFZ) Phone +49-341-235-1764
Tilo Arnhold (UFZ press officer)
Phone: +49-341-235-1269
Group Biological Field Measuring Methods
Biosensors - Development and Application
Aptamers - New Molecular Recognition Elements
Strehlitz, B.; Stoltenburg, R. (2009): SELEX and its Recent Optimizations
in: Mascini, M.: Aptamers in Bioanalysis. WILEY Interscience. 1. Auflage - März 2009.
328 Seiten, 109,- Euro. ISBN-13: 978-0-470-14830-3
B.; Nikolaus, N.; Stoltenburg, R. (2008): Protein Detection with Aptamer Biosensors. Sensors 8, 4296-4307; DOI:
Nikolaus, N.; Strehlitz, B. (2008): Amperometric Lactate Biosensors and their Application in (Sports) Medicine, for Life Quality and Wellbeing. Microchimica Acta 160 (1-2), 15-55,
Stoltenburg, R.; Reinemann, C.; Strehlitz, B. (2007): SELEX
- a (r)evolutionary method to generate high affinity nucleic acid ligands. Biomolecular Engineering 24, 381-403,

Mann, D., Reinemann, C., Stoltenburg, R., Strehlitz, B.
(2005) In vitro selection of DNA aptamers binding ethanolamine. Biochem. Biophys. Res. Co. 338, 1928-1934.
Stoltenburg, R., Reinemann, C., Strehlitz, B. (2005):
FluMag-SELEX as an advantageous method for DNA aptamer selection. Anal. Bioanal. Chem. 383, 83-91.

At the Helmholtz Centre for Environmental Research (UFZ) scientists research the causes and consequences of far-reaching environmental changes. They study water resources, biological diversity, the consequences of climate change and adaptation possibilities, environmental and biotechnologies, bio energy, the behaviour of chemicals in the environment and their effect on health, as well as modelling and social science issues. Their guiding research principle is supporting the sustainable use of natural resources and helping to secure these basic requirements of life over the long term under the influence of global change. The UFZ employs 930 people at its sites in Leipzig, Halle and Magdeburg. It is funded by the German government and by the states of Saxony and Saxony-Anhalt.

The Helmholtz Association helps solve major, pressing challenges facing society, science and the economy with top scientific achievements in six research areas: Energy, Earth and Environment, Health, Key Technologies, Structure of Matter, Transport and Space. With 28,000 employees in 15 research centres and an annual budget of around EUR 2.4 billion, the Helmholtz Association is Germany's largest scientific organisation. Its work follows in the tradition of the great natural scientist Hermann von Helmholtz (1821-1894).

Tilo Arnhold | UFZ News
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>