Andor cameras support RNA/DNA research via optical microscopy

The company says active feedback provides subnanometer resolution needed for single molecule analysis.

Low-light-imaging device specialist Andor (Belfast, UK) says two of its back-illuminated EMCCD camera models have been "instrumental" in helping Steven Chu, a Nobel Laureate and US Energy Secretary, push the boundaries of optical microscopy in order to perform molecular analysis in biological research applications.1

One of the cameras involved is the Andor DU860, is capable of acquiring images at 500 frames/s; the other is a DU897 model that can capture individual photons from single fluorescence emitters.

By developing an active feedback system, Chu and his team were able to repeatedly place the centroid of a single fluorescent molecule image anywhere on either of the camera’s CCD arrays and measure its position with sub-pixel accuracy. This means that in conjunction with additional optical beams to stabilize the microscopy system, the traditional errors caused by nonuniformity of chip manufacture can be reduced to subnanometer scale.

As a result, the team was able to develop a two-color, single-molecule imaging system, which achieved image resolutions an order of magnitude greater than the current best super-resolution techniques (5 nm).

Gaining the ability to resolve single molecules at this level has implications for biological research, where it should allow the structure of large, multi-subunit complexes to be analyzed at the single molecule level.

Chu and his colleagues are planning to use the new technique to learn more about the human RNA polymerase II system, which initiates the transcription of DNA, and the molecular mechanisms controlling cell-to-cell adhesion processes.

The resolving power of the new super-resolution technique may also be useful in guiding the design of new photometric imaging systems in fields such as nanometrology, atomic physics, and astronomy, says Andor.

1. A. Pertsindis, y. Zhang, S. Chu, S., "Subnanometre single-molecule localization, registration and distance measurements," Nature, doi:10.1038/nature09163,2010).

-- Posted by Vision Systems Design

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