Dual Polarisation Interferometry

"Making Light Work of Structure-Function Studies"

Farfield's proprietary Dual Polarisation Interferometry (DPI) technology is an exciting, tagless analytical technique with current applications in Surface Science and Biophysics. One key challenge in these fields is the lack of sufficiently sensitive analytical tools to probe the real-time relationship between structural change and molecular function or behaviour.

The DPI technique forms the basis for Farfield's AnaLight® instrument range. DPI uses polarised light from a laser passing down stacked waveguides. These waveguides are incorporated into the structure of our AnaChip™ range. The molecules under study are immobilised (physically or chemically) onto one of a range of AnaChip™ surfaces. The evanescent field emanating from the top waveguide interrogates the immobilised molecules. Changes in the resulting optical interference pattern are caused by changes in the structure and/or mass of the immobilised molecules. Thus DPI provides the exquisite sensitivity to give previously unavailable insights into the structural changes taking place in molecular systems as they function and interact.

AnaLight® DPI instruments are quantitative analytical tools, not sensors. AnaLight® routinely and reproducibly provides quantitative data on real-time changes in dimension (resolution <0.1Å) and density (resolution <0.1 picogram/mm2) of the immobilised molecules, without recourse to tagging. This allows accurate calculation of further parameters including mass, surface coverage and concentration. This means, for example, that AnaLight® instruments can reliably detect molecules below 50Da binding to immobilised macromolecules of up to 100,000Da with a mass resolution of <5Da.

Bridging Technology: Data generated on any AnaLight® instrument is absolute. In simple terms, AnaLight® instruments are 'molecular microscopes' whose quantitative structural measurements can be compared directly with complimentary techniques such as x-ray crystallography, NMR and neutron reflection, whilst also being capable of functional measurement at far higher sensitivity and with less ambiguity than classical optical and acoustic biosensor technologies.

Dual Polarisation Interferometry (261KB)

Visit the InfoZone to learn more about the principles behind the DPI technique.