Benefits of Using Phase Plates in Industrial and Laboratory Processes
Phase plates, also called microplates, are an innovative technique in the field of optoelectronic microscopy. They give increased contrast and higher signal-to Noise ratio in high resolution imaging of ultra-violet radiation sensitive samples. The main advantage is that the thickness of the plate can be varied according to the type of sample to be imaged. Thin film phase plates have so far been tested only in biophysical applications and have showed promise for cryo tomography and single cell detection.
Single crystalline microphoton microscopes using light emitting diodes (LEDs) allow for efficient visualization of chemical reactions and biological probes in living tissues. By contrast, electron microscopes using electrons emit blue light and thus cannot reveal the details of complex biological molecules. In such cases the phase plates need to be replaced by other techniques such as fluorescence microscopy and chemical absorption. But another major plus with phase plates is their great sensitivity. They can image extremely small particles, such as viruses, bacteria, and even electrons and atoms.
Phase plates work well for studying single crystal materials like glass, silver, titanium, or titanium dioxide. They can be used to study chemical reactions in solids and liquids and in living tissues. When multiple crystals are involved, the use of objective lens is appropriate. However, the multiple objectives in electron microscopy make phase plates impractical for this technique. It also limits the number of objectives achievable.
Recently, two research teams independently developed a novel method for phase contrast enhancement in electron microscopy experiments. One group discovered the existence of a new type of dispersion that occurs at certain temperatures when highly excited atoms of interest are present. The second team successfully applied this method to an experimental study on hydrogen bonding of oxygen molecules. Their results were published recently in Nature Chemistry. They published their study in Google scholar.
According to them, using a combination of diamond and phase plates in electron microscopy enables the researcher to achieve much better image contrast than with other techniques. Diamond phase plates, they found, have a significant effect on the signal to noise ratio. Basically, the better the signal to noise ratio, the higher the quality of the image and the better the STED microscopy images become. Their findings were published in Nature Chemistry.
This recent finding makes use of phase plates, which have been previously seen only in gas-phase studies of electron microscopy, in electron microscopy applications. Because the diamonds improve the signal to noise ratio significantly, the researchers argue, it makes use of these special diamonds the ideal choice for microscopy applications. In fact, they claim that their improved contrast in cryo Electron Microscopy experiments was up to seven times better than what one could achieve using standard electron microscopes. It’s important to note, however, that this finding has only been tested on sheets of glass, which are non-crystalline, which do not feature a refractive chromium oxide coating.
They believe that future studies should look more closely at the chemical makeup of various thin-film phase plates and probe the effects of various coatings on the signal to noise ratio in biological systems. They also hope to test the effects of a thicker zeolite layer on biological systems, particularly in systems that may contain both hydrogen and oxygen. Zernike Phase Plate Technology is only just starting to make its way into clinical and pre-clinical laboratories, and the researchers admit that there are still many challenges ahead. Other teams have already begun looking into the phenomenon of improved contrast in electron microscopy with the use of thin-film phase plates.
Although the technology is relatively new to the scientific community, phase plates have been used for decades in industrial and laboratory processes. There is no telling if the widespread use of this technology will prove beneficial for those with eye disorders, cancer patients, or anyone else with vision impairments. However, researchers are hopeful that the introduction of the volta phase plate will help advance the field. “This is exciting technology,” said Jay Calvert, who is a professor at the University of Iowa. “It has a lot of promise for people with visual impairments.”
