Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Reveal the Enemy

20.07.2009
Carbon nanotubes and aptamers: new biosensor detects extremely low bacteria concentrations quickly, easily, and reliably

Bacterial diseases are usually detected by first enriching samples, then separating, identifying, and counting the bacteria.

This type of procedure usually takes at least two days after arrival of the sample in the laboratory. Tests that work faster, in the field, and without complex sample preparation, whilst being precise and error-free, are thus high on the wish list.

A Spanish research team headed by Jordi Riu and F. Xavier Rius at the University Rovira i Virgili in Tarragona has now developed a new technique to make this wish come true. With a novel biosensor, they have been able to detect extremely low concentrations of the typhus-inducing Salmonella typhi.

As reported in the journal Angewandte Chemie, their new method is based on electrochemical measurements by means of carbon nanotubes equipped with aptamers as bacteria-specific binding sites. If bacteria bind to the aptamers, the researchers detect a change in electrical voltage.

Aptamers are synthetic, short DNA or RNA strands that can be designed and made to bind a specific target molecule. An aptamer that specifically binds to salmonella has recently been developed. The Spanish researchers chose to use this aptamer for their biosensor. By means of additional functional groups, they securely anchored the aptamers to carbon nanotubes, which were deposited onto an electrode in an ultrathin layer.

In the absence of salmonella, the aptamers fit closely against the walls of the carbon nanotubes. If the biosensor is put into a salmonella-containing sample, the microbes stick to the aptamers like flies to flypaper. This influences the interaction between the aptamers and the nanotubes, which makes a change in the electrode voltage noticeable within seconds.

Using this biosensor, the researchers were able to detect a bacterial concentration equivalent to one salmonella bacterium in 5 mL of medium. Quantitative measurements were possible down to a concentration of about 1000 salmonella per milliliter. This biosensor is specific: it does not react to bacteria other than Salmonella typhi. “Our new technique makes the detection of micro-organisms as fast and simple as the measurement of pH value,” say Riu and Rius.

Author: Jordi Riu, Universitat Rovira i Virgili, Tarragona (Spain), mailto:jordi.riu@urv.cat

Title: Immediate Detection of Living Bacteria at Ultralow Concentrations Using a Carbon-Nanotube-Based Potentiometric Aptasensor

Angewandte Chemie International Edition, doi: 10.1002/anie.200902090

Jordi Riu | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society

nachricht 127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>