A direct electron detector for electron cryo-microscopy. (360G-Wellcome-101488_Z_13_Z)

The field of electron cryo-microscopy (cryo EM) is playing an increasingly important role in structural molecular and cellular biology, owing to advances in hardware and software that improve the image quality and facilitate the work. A major limitation has been the low quality of image recording, because of the low contrast and high radiation sensitivity of biological samples. Digital detectors are essential for high-throughput data collection, but the commonly used CCD detectors have worse res olution than photographic film. They convert electrons into visible light for signal recording, and this conversion degrades the image quality. Recent developments have led to commercially available direct electron detectors giving far superior performance for EM, with excellent test results already published. They provide information to the theoretical limit of resolution, whereas CCD images lack the higher resolution details. The signal/noise ratio of direct detectors at maximum resolution is at least 10-fold superior, providing major advantages for both single particles and cryo tomography. Since cryo EM operates at the limits of detection for delicate biological structures, this instrumental advance makes a vast difference to feasibility, resolution and efficiency of data collection. The resulting improvements in biological output lead to a much better use of expensive facilities.