In August 2006 CBST received a $599K, 2-year National Science Foundation Major Research Instrumentation award for a project lead by Thomas Huser, Chief Scientist at CBST and Associate Professor in the Department of Internal Medicine at UC Davis. The project aims to develop, commercialize, and enhance a high-resolution structured-illumination (SI) fluorescence microscope system following a design originated at the University of California, San Francisco (UCSF) called OMX (Optical Microscope eXperimental). This first commercial OMX system will be located at the newly opened NSF Center for Biophotonics Science and Technology (CBST) Oak Park Research Building in Sacramento, CA. The OMX will be co-developed with an industrial partner (Applied Precision (API)).

The prototype OMX system at UCSF has demonstrated the highest lateral resolution of any wide-field light microscope, achieving <100 nm resolution. The microscope operates by using illumination with a periodic intensity pattern that encodes high spatial-frequency information from the sample, not seen by conventional microscopes, into multiple lower frequency moiré images. These images are then used to computationally reconstruct the real image at 2 to 5 times the diffraction-limited resolution. In addition to enhanced spatial resolution, the OMX microscope has exceptional light collection efficiency, is designed for ultra-stable operation with minimal thermal drift, and is able to perform high-speed 3D imaging with up to 4 cameras simultaneously.

Widespread use of this super-resolution microscope is expected to lead to many new discoveries in cellular biology. OMX provides excellent coverage of the intermediate length scales bridging the gap between standard fluorescence microscopes (~ 250 nm) and electron microscopy. Many important biological applications lie in this intermediate range, such as resolving sub-cellular structures, the organization of chromosomes, the assembly of large protein complexes, viral structure, and processes affecting cellular organelles in addition to non-biological applications in semi-conductor metrology and high-resolution imaging of nano-scale devices and materials.

A group of multidisciplinary users in the Colleges of Biology, Engineering, and the School of Medicine at UC Davis, other CBST partner institutions including Mills College, and Lawrence Livermore National Laboratory (LLNL) have expressed an interest in using the final instrument to significantly advance their research. The OMX system will also be used for the training of students and researchers as part of CBST courses in advanced microscopy.

The same random arrangement of 50 nm fluorescent microscpheres on a glass microscope slide are shown in the three images shown above. The image on the left is obtained with a diffraction limited conventional light microscope. The center image is obtained using linear structured illumination (SI) which improves the resolution by 2X. The image on the right is obtained using non-linear SI and gives a 5X improvement in resolution. The baseline OMX microscope will be capable of linear structured illumination and can allow for implementation of non-linear versions of SI. For more details see Mats Gustafsson’s publication “Nonlinear structured-illumination microscopy: Wide-field fluorescence imaging with theoretically unlimited resolution” in the Sept 13, 2005 issue of PNAS, Vol 102(37), pp. 13081-13086– describing the method for achieving an unprecedented 50 nm spatial resolution in widefield fluorescence microscopy and showing that spatial resolution is in principle only limited by signal and noise considerations.

For more information about this article, please contact Prof. Thomas Huser (trhuser@ucdavis.edu), Prof. John Sedat (sedat@msg.ucsf.edu), or Prof. Mats Gustafsson (mats@msg.ucsf.edu).