URBANA, Ill. A sub-cellular world has been opened up for scientists to study E. coli and other tissues in new ways, thanks to a microscopy method that stealthily provides three-dimensional, high-quality images of the internal structure of cells without disturbing the specimen.
By combining a novel algorithm with a recently-developed add-on technique for commercial microscopes, researchers at the University of Illinois have created a fast, non-invasive 3D method for visualizing, quantifying, and studying cells without the use of fluorescence or contrast agents.
In a paper published online today in the journal PLoS ONE, the researchers who developed the technique reported that they were able to use it to visualize the E. coli bacteria with a combination of speed, scale, and resolution unparalleled for a label-free method.
The method is based on a broadband interferometric technique known as Spatial Light Interference Microscopy (SLIM) that was designed by Beckman Institute researcher Gabriel Popescu as an add-on module to a commercial phase contrast microscope. SLIM is extremely fast and sensitive at multiple scales (from 200 nm and up) but, as a linear optical system, its resolution is limited by diffraction.
By applying a novel deconvolution algorithm to retrieve sub-diffraction limited resolution information from the fields measured by SLIM, Popescu and his fellow researchers were able to render tomographic images with a resolution beyond SLIM's diffraction limits. They used the sparse reconstruction method to render 3D reconstructed images of E. coli cells, enabling label-free visualization of the specimens at sub-cellular scales.
Last year the researchers successfully demonstrated a new optical technique that provides 3D measures of complex fields called Spatial Light Interference Tomography (SLIT) on live neurons and photonic crystal structures. In this project they developed a nov
|Contact: Sue Johnson|
Beckman Institute for Advanced Science and Technology