Electron microscopy tool improves drug R&D
the European research market allowing researchers for the first
time to directly image cells in their native wet environment with a
standard scanning electron microscope (SEM).
The technology completely isolates wet samples from the vacuum in the microscope chamber. This makes possible the imaging of fully hydrated samples and opens up new opportunities for application-specific tools for improved drug discovery, and advancing treatment and diagnostic solutions for the medical and pharmaceutical markets.
Ron Levin, marketing and sales manager for the European market, told DrugResearcher.com: "The QX capsules are especially relevant for pharmaceutical companies that are investigating receptor membranes. This is a tool for drug discovery, as it allows detail not previously achievable."
The QX capsule uses an ultra thin membrane that is transparent to an electron beam but impervious to water and strong enough to resist a one-atmosphere pressure difference.
It combines the function of a specimen holder or tissue specimen holder with an electron-transparent, vacuum-tight window. It is used to separate the wet specimens from the SEM vacuum enabling researchers to directly image unstained, unfixed cells and tissues including the imaging of entire cell membranes and internal structures with any SEM.
Levin said: "The advantage of observing cells in their native wet environment is you get to see the cells with an SEM magnification in their natural state. The SEM vacuum causes the cell or sample of interest to evaporate resulting in a skewed image of the material."
"A prime example of this is a cell membrane. In a dry environment the membrane will collapse inside."
Imaging of samples in the QX capsule can be achieved with backscattered electron detection, X-ray detection or light detection revealing structure as well as material composition.
Levin said: "Although the capsule is a single-use device it is affordable and compares favourably to other methods of analysis in terms of savings in lab time and reagent cost."
Ory Zik, company founder and co-inventor of the QuantomiX technology added: "The capsule fits existing electron microscopes, working best with the new generation microscopes that have better detectors and computer interface."
"Previously, all biological and other water-containing samples could not be imaged in a wet state at atmospheric pressure and room temperature."
While resolution is slightly lower than in dry SEM samples, depending on the specific sample and the SEM model used, a resolution of 20 nm can be resolved. With Field Emission Gun (FEG), 10 nm gold particles can be routinely visualised. The resolution of fluid samples that do not contain metals, such as emulsions, is approximately 100 nm.
Levin said: "The lower resolution only applies to certain materials in a live cell. Obviously there will be limitations. This drawback can be solved by the staining and fixing of cells but this will affect the environment the cell is suspended in."
One advantage of the QX capsule technology is the imaging of the size and distribution of cellular lipids, particularly in research aimed at improving the diagnosis and management of diseases such as obesity and diabetes, said QuantomiX.
Barbara Corkey, professor of medicine and biochemistry and director in the Obesity Research Centre at Boston University said: "QuantomiX's QX-capsule enabled us to quantitatively study lipid accumulation, in a way that we could not do before."
Levin said: "The lipid in dry environment will evaporate. In the capsule the lipid will be kept in its natural environment and on a SEM image it will appear as a darker, distinguishable colour indicating its presence This is useful for comparing cells of a normal and obese person as actual lipid droplets can be accounted for."
The company which made its products available to the US market in the second quarter of 2004 and is now to Europe expect to further develop its products and technology for use in future medical diagnostic and industrial applications.
The technology debuted to the European scientific community at an exhibits and a workshop at the Micro Sciences 2004 meeting in London.
The initial findings using this technology were published in the March 9, 2004 issue of the Proceedings of the National Academy of Sciences (PNAS Volume 101 no. 10).
