A silver bullet for DNA separation

19 October 2010

A simple and greener way to separate DNA using branched silver microparticles is revealed by scientists in China.

Separation techniques are required for a multitude of applications from disease diagnosis to environmental monitoring. Many materials are used to separate complex chemical mixtures with more recent interest focussing on magnetic nanoparticles as they can be easily recovered.

However, preparation of magnetic nanoparticles requires a large amount of organic reagents and energy and it can be difficult to get the right dimensions. Now Erkang Wang and co-workers at the Changhun Institute of Applied Chemistry have developed crystalline silver particles, know as dendrites, as an alternative to magnetic nanoparticles for DNA separation. 'The development of a facile, economical and simple strategy to synthesize a new monodisperse, easily-modified substitute for magnetic nanoparticles with controlled size is a great challenge' explains Wang.

Nanoparticles can be used to detect DNA then be easily separated using gravity

Wang used the silver microdendrites to analyse human T-lymphotropic virus types I (HTLV-I), which is associated to adult T cell lymphoma/leukemia. The silver micro-dendrites were firstly modified with a probe to target the DNA and a second fluorophore labelled probe was used to enable detection with a confocal laser scanning microscope. The separation uses gravity thus eliminating the need for magnetic separation and simplifying the process.

'If the described approach would extend the toolbox of nanoparticle-based bioanalytical techniques by providing another, alternative separation technique without the requirements of either magnetic particles nor centrifuges it would be a welcome addition to the field,' comments Wolfgang Fritzsche, an expert in nanobiophotonics at the Institute of Photonic Technology in Jena, Germany.

'Many other chemicals such as proteins, organic pollutants and even heavy metal ions could be detected using this technique,' adds Wang and adds that the next challenge is to develop this technique for real sample analysis.

Leanne Marle


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