Fluorescence microscopy techniques have become the norm for studying fluorescently labelled proteins and the effects that drug molecules have on their expression and function. However, one limitation has always been in generating spatial information about where the molecules of interest are located. The new technique, known as Photo-Activated Localisation (PAL) microscopy enables proteins to be located in a cell to a resolution of 20nm - an order of magnitude higher than conventional fluorescence techniques such as confocal microscopy achieve. "We were very excited by the potential of PAL microscopy from the moment we started to assess the technique. It not only offers the highest resolution available, but also achieves this in a very light-efficient manner. PAL microscopy has also been demonstrated on multi-colored samples, an essential prerequisite for accurate colocalization studies," said Dr Bernhard Zimmermann, senior product manager at Carl Zeiss MicroImaging. "With the integration of PAL microscopy, the affordable personal super-resolution system, into microscope systems from Carl Zeiss, our customers will get for the first time a complete picture of the ultrastructure underlying the cellular architecture and functioning. This truly reveals new insights into how life is organized at the subcellular level." The technique was developed by Dr Eric Betzig and Dr Harold Hess at the Janelia Farm Research Campus of the Howard Hughes Medical Institute (HHMI) in Virginia, USA, and is so powerful that it allows scientists peering inside cells to determine the precise location of individual proteins within the cells. Traditional microscopes have struggled to resolve the organisation of most small cellular compartments but Dr Betzig and Dr Hess overcame this by only sparsely photo-activating fluorescent molecules such that individual molecules are further apart. The activated molecules positions are determined before the activation process is repeated. Assembling individual images into a single image enables a resolution to be achieved that is close to that of an electron microscope. "We share a deep commitment with Carl Zeiss to see this technology reach a broad community of researchers in a form that upholds high technical standards and will truly further their research," said Dr Hess.