New technique to image cell interior
A new method of imaging cells is allowing scientists from Queen Mary University of London to see tiny structures inside the nucleus of the cell for the first time.
Recent advances in super-resolution microscopy have made it possible to study complex structures smaller than 200nm, but the techniques can only produce very clear images of structures at the bottom of the cell.
This new imaging system – Spinning Disk Statistical Imaging (SDSI) – has made it possible to image structures smaller than 80nm anywhere in the cell. The technique was developed by Dr Neveen Hosny working with Professor Martin Knight, and Dr Ann Wheeler.
“The spinning disk microscope produces focused images at high speed because it has a disk with an array of tiny holes in it which remove the out of focus light,” said Wheeler. “We have combined this microscope with new fluorescent probes, which switch between a bright and dark state rapidly. This system is now allowing us to see structures three times smaller than could usually be seen using standard light microscopes.”
The technique has been used to visualise chromatin – the protein structure that controls DNA expression and the nuclear envelope – and to image focal adhesions, sub-cellular macromolecules which the cell uses to attach to its environment
“Although it was previously possible to see these structures, our method provides a greater degree of detail. It also allows us to look at protein complexes which are smaller than 200nm in the nucleus, which hasn’t been done before,” Wheeler said.
“Super resolution microscopy is a major step forward and we are looking forward to using this technology in a wide range of applications from stem cell behaviour to understanding arthritis or the development of nanomedicine,” said Knight.
The microscope is housed in its own room with a carefully controlled environment to miminise vibrations. Dr Wheeler added: “We will be continuing to develop the technology to improve the fluorescent probes used for this technique and also applying it to cellular processes such as invasion in cancer.”