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sábado, 3 de março de 2012

Amazing nano rockets in five easy steps (Nature Chemistry)


Jet engined nano size rockets, which contain a cargo may be a solution for several delivery jobs in the human body. And no, this is not science fiction, it is science.

Nature Chemistry publishes the invention by chemists of the Institute for Molecules and Materials (IMM), Radboud University Nijmegen online on February 26. ‘We think this is the first realistic and useable nano motor,' the researchers say.
Useable nano motor
Making a nano motor has been a dream of many researchers in the field. Several impressive attempts have been made, but at the end of the day they turned out to be too difficult to construct , had poor motor performance, or ‘square' wheels.

We work from a different angle and use nature as inspiration, but do not directly copy natural systems. In nature cells transport things all the time using motor systems,' says Prof. Jan van Hest.
Our nano rocket is made building on a simple design, using so-called polymersomes , which are ball shaped containers, as the main component. Since we master the craft to include different types of molecules in these containers and link them to marker molecules or functional enzymes, and peptides on the outside, we foresee practical use of these engines in the near future, for instance as drug delivery systems.'

So what is the IMM recipe for a nano rocket? 
> Step one: let polymers - hydrophobic on one side and hydrophilic on the other -- assemble themselves into neat nano balls.
> Step two: stump your nano balls into nano bowls using osmotic pressure.> Step three: place a reactive particle in each nano bowl, and stop it from moving out again. ‘We used a catalytically active platinum nanoparticle in this case,' Dr. Daniela Wilson explains. ‘Your nano rocket is almost ready for use now.'
>Step four: drain the nano rockets from the solution.
> Step five: place your nano rockets into a suitable fuel (hydrogen peroxide in this case) and watch them closely with your microscope. See how the escaping exhaust gasses propel your nano rocket.

The nanoparticles are about ten times smaller than a bacterium. As long as they are not a part of some form of fuel they move very little (video below) and a bit crisscross. That's very different when they are a part of any form of fuel (video below). Right now, the Nijmegen-based researchers are learning to steer the rockets, using a gradient of fuel concentration. To be continued!

Autonomous movement of platinum-loaded stomatocytes
Daniela A. Wilson, Roeland J. M. Nolte and Jan C. M. van Hest, Institute for Molecules and Materials, Radboud University Nijmegen, the Netherlands
Advance Online Publication on Nature Chemistry's website on 26 February
The DOI for this paper is

The following funding acknowledgements from the authors appear at the end of the paper:
This work was supported by the Dutch Science Foundation (NWO/CW) under the VICI project ‘Kinetically controlled peptide-polymer artificial organelles' (Jan van Hest). Daniella Wilson and Roeland Nolte acknowledge financial support from the Royal Netherlands Academy of Science.