Nano-pen prints polymers

[nanoorg]

Researchers in Israel and France have devised a new technique to make molecularly imprinted polymers using a nanofountain pen. The method paves the way to highly stable nanoarrays for multi-analyte detection.

Micro- and nano-biochips could expand the use of arrayed biosensors in applications such as point-of-care clinical testing, environmental monitoring and homeland security. Normally, these biochips employ enzymes or antibodies as sensors but these molecules can be unstable. Moreover, a natural receptor for a particular target may not always exist. Scientists would therefore like to create new, tailor-made receptors for particular molecular targets.

Levi Gheber's team at Ben-Gurion University of the Negev in Beer-Sheva, together with Karsten Haupt's group at the Compiègne University of Technology, have now shown that they can do just this. Anne-Sophie Belmont, in Haupt's group, and colleagues made single nanostructures with molecular imprints that can be positioned with high precision using a nanofountain pen. The pen is a hollow glass capillary drawn into a very sharp tip with an aperture of just a few hundreds of nanometres.

The "ink" – which can be proteins, polymers, DNA and enzymes – only flows out of the tip of the nanopipette when it is in contact with a surface to deposit miniscule amounts of solution. The pipette is mounted as the probe of an atomic force microscope (AFM) and its position is controlled with nanometre precision. This technique is called MIP by researchers for molecularly imprinted polymers.

The device can print without lifting the pen off the substrate and the amount of "ink" in the pen's reservoir is practically unlimited at these scales.

The main advantage of the technique is that proteins, enzymes and polymers can be printed onto glass, gold-coated and silicon substrates providing nanoarrays that can detect multiple analytes based on MIPs that have high stability compared to biological receptors. The arrays can be imprinted with target molecules for which natural receptors may not exist.

The team is now working on printing MIPs that can detect several analytes on the same array. It also hopes to develop label-free detection techniques for binding on such small MIP structures.

The researchers reported their work in Appl. Phys. Lett..


Source: http://nanotechweb.org/articles/news/6/5/26/1


Story posted: 4th June 2007