This issue showcases the winners of the second annual Microscopy Today Innovation Awards competition. These awards were established to honor innovative microscopy-related products and methods that appeared in the previous year.

Localizing specific proteins within cells, tissues, and organisms has been a goal of microscopists for generations. In the early 1990s, a breakthrough was made when a molecule originally derived from a jellyfish was introduced as a probe for fluorescence microscopy. This molecule is green fluorescent protein (GFP), and it has become well known for its usefulness in localizing proteins at the level of the light microscope. It is also well known that electron microscopy (EM) offers far superior spatial resolution over light microscopy, but the application of probes to localize specific proteins has required antibodies conjugated with colloidal metals (such as gold). Delivery of antibodies into the cell commonly requires detergents to permeabilize the cell membrane, which compromises the ultrastructural detail. Another breakthrough was recently published on-line by Xiaokun Shu, Varda Lev-Ram, Thomas Deerinck, Yingchuan Qi, Ericka Ramko, Michael Davidson, Yishi Jin, Mark Ellisman, and Roger Tsien: they have developed a method similar to using GFP for light microscopy, but for specifically tagging proteins at the EM level.

A number of proposed technologies involve the controlled implementation of biologically induced carbonate mineral precipitation in the geologic subsurface. Examples include the enhancement of soil stability, immobilization of groundwater contaminants such as strontium and uranium, and the enhancement of oil recovery and geologic carbon sequestration via controlled permeability reduction. The most significant challenge in these technologies remains to identify and better understand an industrially, environmentally, and economically viable carbonate precipitation route.

Understanding the structure and dynamics of the protein complexes that underlie cellular function is a central scientific challenge. Biochemical techniques used to identify such complexes would be enhanced by the imaging of specific molecular positions in the context of intact cells, with protein-scale resolution (on the order of a few nanometers). Currently, though, nanometer resolution can only be achieved at the cost of less-direct imaging of the unperturbed cell. Cellular ultrastructure is traditionally studied by transmission electron microscopy (TEM), which yields nanometer resolution on embedded and stained sections, or cryo sections. These cellular samples are neither intact nor in their native liquid state. Light microscopy is used to image protein distributions in fluorescently labeled cells in liquid to investigate cellular function, but even recent improvements in resolution by nanoscopy techniques are still insufficient to resolve the individual constituents of protein complexes. Thus, development of techniques capable of high-resolution imaging in native cellular states would contribute significantly to our understanding of cellular function at the molecular level. The development of liquid compartments that include electron-transparent silicon nitride membrane windows has led to the introduction of a novel concept to achieve nanometer resolution on tagged proteins in cells.

When studying highly resolved scanning electron microscope images of cell surfaces, the question arises, whether the observed patterns are real or just artifacts of the cell preparation process. The following steps are usually necessary for preparation: fixation, drying, and metal coating. Each step might introduce different artifacts. Clever techniques have been developed to dry cells as gently as possible, for example critical point drying with different organic solvents and CO2. Instrument manufacturers also have taken account of this issue, for example, through the realization of the environmental scanning electron microscope (ESEM), operating with a low-vacuum environment saturated with water so that samples might stay hydrated. Another approach is the extreme high-resolution scanning electron microscope (XHR SEM), where the electron beam is decelerated shortly before reaching the sample. This technique requires no metal coating of the sample. Cryo-SEM also may be used, where no sample preparation is required beyond freezing in a high-pressure freezer or other cryo-fixation device. Then the cell can be examined in the frozen, hydrated state using a cryostage. However, at least some kind of preparation is necessary for SEM imaging, and we wanted to find out what changes the preparation makes on the cell surface.

“Second best no more” was the title of an article written by David C. Joy for Nature Materials. The article was for highlighting a breakthrough made by a team formed between Brookhaven National Laboratory (BNL, USA) and Hitachi High Technologies Corporation (HHT, Japan). Sub-angstrom secondary electron (SE) images were obtained on a Hitachi HD-2700, which is a combined scanning electron microscope (SEM) and scanning transmission electron microscope (STEM) operating at a maximum accelerating voltage of 200 kV. For the first time, single atoms and atomic lattices on crystal surfaces are unambiguously presented in SE images.

Quantifying an X-ray spectrum is the process of converting a measured spectrum into an estimate of the composition of the material from which the spectrum was collected. In a certain sense, interpreting X-ray spectra is very simple. A spectrum from even the most complex material can be thought of as a sum of spectra from the constituent elements (see Figure 1). To first approximation, if you know the spectrum for the constituent pure elements, you can estimate the spectrum for the complex material. Regardless of the software vendor or the name of the algorithm, this is the basis for quantification of all X-ray spectra.

Metallic and non-metallic nanoparticles (NPs), ranging in size from 1–200 nm, have unique functional properties that differ from their bulk materials and their component atoms or molecules. These unique properties have driven the demand for nano-sized materials and new methods to synthesize NPs, which are used in drug delivery systems, bio-imaging agents, catalysts, photonics, and optical devices. Inorganic NPs can be synthesized with a variety of methods that impart size, shape, and other structural properties. Cobalt-based NPs, for instance, display unique size and shape-dependent magnetic properties, while the band gap, UV blocking properties and stability of zinc oxide (ZnO) NPs enable new applications in products ranging from cosmetics to solar cell power.

Microscopy Today congratulates the second annual group of Innovation Award winners. The ten innovations described below move several microscopy techniques forward: light microscopy, scanning probe microscopy, electron microscopy, and analytical microscopy. These innovations will make imaging and analysis more powerful, more flexible, more productive, and easier to accomplish.

Although the last decade in electron microscopy has seen tremendous gains in image resolution, new challenges in the field have come to the forefront. First, new ultra-sensitive instruments bring about unprecedented environmental specifications and facility needs for their optimal use. Second, in the quest for higher spatial resolutions, the importance of developing and sharing crucial expertise—from sample preparation to scientific vision—has perhaps been deemphasized. Finally, for imaging to accelerate discoveries related to large scientific and societal problems, in situ capabilities that replicate real-world process conditions are often required to deliver necessary information. This decade, these are among the hurdles leaders in the field are striving to overcome.

Linkam Scientific Instruments have been chosen by the Physics Department of the University of Liverpool to study the effects of controlling stresses applied during the growth of collagen secreted from human fibroblast cells. The research goal of senior research assistant, Dr. Caroline Smith, and her colleagues at the University of Liverpool is to advance the treatment of tendon injuries by developing a method of growing oriented human collagen.

Selected postings to the Microscopy Listserver from May 1, 2011 to July 1, 2011. Complete listings and subscription information can be obtained at http://www.microscopy.com. Postings may have been edited to conserve space or for clarity.

Following is a list of microscopy related meetings and courses. The editors would greatly appreciate input to this list via the electronic submission form under “events/other microscopy events” at the MSA webpage: www.msa.microscopy.com. We will gladly add hypertext links to the notice on the web and insert a listing of the meeting in the next issue.