Nanoscope breaks small item record
Scientists may soon be able to watch viruses in action for the first time using the world's most powerful optical microscope.
British researchers from the University of Manchester helped develop the instrument, which has broken all records for magnifying small objects using ordinary white light.
The "microsphere nanoscope" is capable of examining objects as small as 50 nanometres across - 20 times smaller than the present limit for optical microscopes of around one micrometre, or 0.001 millimetres.
Theoretically the microscope should allow scientists to look at tiny details inside cells and even "live" viruses.
Electron microscopes, which use a focused beam of electrons instead of light, can image extremely small objects but have limitations. Either they are designed only to view surface details, or they require extremely thin specimen sections, making it difficult to image fine biological structures.
The new instrument, described in the journal Nature Communications, employs "superlenses" in the form of tiny "microspheres" to push the technical boundaries of optical microscopes.
Professor Lin Li, from the University of Manchester's School of Mechanical, Aerospace and Civil Engineering, who led the project with colleagues from Singapore, said: "This is a world record in terms of how small an optical microscope can go by direct imaging under a light source covering the whole range of optical spectrum.
"Not only have we been able to see items of 50 nanometres, we believe that is just the start and we will be able to see far smaller items. Theoretically, there is no limit on how small an object we will be able to see.
"The common way of seeing tiny items presently is with an electron microscope, and even then you cannot see inside a cell - only the outside. Optical fluorescence microscopes can see inside the cells indirectly by dying them, but these dyes cannot penetrate viruses.
"Seeing inside a cell directly without dying and seeing living viruses directly could revolutionise the way cells are studied and allow us to examine closely viruses and biomedicine for the first time."