3D video microscope helps scientists study HIV
A microscope system that captures 3D video of cells at very high resolution is helping scientists understand how AIDS and other diseases spread.
The Deltavision OMX Blaze system can reveal the internal structures of living cells that are too small to be seen with visible light and has enabled researchers at the University of California, Davis, to examine how the human immunodeficiency virus (HIV) moves between cells.
The team at the Center for Biophotonics Science and Technology (CBST) has been trialling the prototype technology since June 2011 to help its developer, GE Healthcare-owned Applied Precision Inc (API), refine the device for wider distribution.
‘We anticipate it being used heavily to image microbiology samples of infectious agents that are responsible for a lot of the deaths of people worldwide and understand those mechanisms,’ Paul Goodwin, director of advanced applications at API, told The Engineer.
The system is particularly useful for studying HIV because much of the viral information is transferred between cells without being exposed to the outside environment — one of the reasons why the virus is so difficult to fight with antibodies.
A previous generation of the OMX technology enabled the capture of super-resolution 3D image data but the Blaze model is able to acquire such images fast enough to capture dynamics in living cells, effectively at a rate of one every 10 seconds.
Other imaging systems that allow the examination of structures smaller than the wavelength of light, such as electron microscopes, typically require samples to be chemically ’fixed’ and viewed in a vacuum so are unsuitable for monitoring living cells over time.
API’s system, based on research from the University of California, San Francisco, uses fluorescence imaging whereby cells are illuminated with a specific pattern of light. The information captured in the images is used to calculate the higher resolution structures.
By rotating and shifting the light pattern across 15 different positions, the system can capture multiple images at a rate of 105 per second that are processed to create moving 3D pictures with data about the exact positions of cell structures.
API had to develop new illumination technology and new camera technology using CMOS processors to enable the system to work fast enough, said Goodwin.
‘The technology that was required to achieve this was not only being able to change the light quickly, but we needed new camera technology that would create efficiency and low noise to collect a lot of images quickly.’
The company expects to make the device available next month after final improvements from the trial but also hopes to develop it further to increase the time it can observe a sample for, which is limited by the fluorescence of the sample to several minutes.
‘We have a good idea now of the things we need to improve in terms of the illumination, the sample preparation and the post-processing of the data to be able to maximise the information and reduce the amount of light on the sample,’ said Goodwin.