Monday, May 28, 2007

DNA Photonics

DNA – “the molecule of Life” – exciting new material for fabricating Photonics devices with improved properties.

The most important and famous biomaterial known to man is DNA, the polymeric molecule that carries the genetic code in all living organisms.

The continuous effort is being taken to develop photonics devices based on Organic Materials. It is inspired by possible use of range of materials and low cost production.

One of good example of this trend is Organic LED, which is at the heart of display technology now breaking into consumer electronics market and replacing small LEDs.

The DNA molecular structure (the famous double helix) consists of two intertwined spirals of sugar and phosphate molecules linked by hydrogen-bonded base pairs. The width of the double helix is about two nanometres and the length of the DNA molecule depends on the number of base pairs (about a third of nanometre per base pair). Synthesizing or manipulating DNA molecules by physical and chemical means can lead to a variety of structures at the nanoscale. Potential applications include assembly of molecular electronic devices, nanoscale robotics, DNA-based computation, for example. Synthetic DNA is also the material of choice for fundamental studies of electronic processes resulting from the interaction of DNA molecules with light.

DNA photonic devices can be split into two categories — wet devices and solid state devices. The wet category contains primarily optofluidic devices, where the DNA molecules are present in either an aqueous or organic-solvent solution and are transported in a fluid under the influence of electric fields or fluid flow.

In contrast, solid-state devices are based on thin films of DNA. DNA films are produced by solution methods at present, where a reaction between the DNA and a cationic surfactant (such as cetyltrimethyl ammonium — CTMA) produces a DNA–lipid complex that is insoluble in water but soluble in alcohols.

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