Key factors to consider when purchasing a microscope.
Upright or upside down?
Of course, depending on the intended application and the sample you wish to observe, it will help you to immediately decide whether you need an upright or an inverted microscope, the difference being the optics positioned above or below the sample. "But another thing to consider is not only the sample itself, but also the vessel in which you're looking at it," says Olympus vice product Lauren Alvarenga. For microscopic imaging of samples in flasks or plastic dishes, you'll need an inverted microscope with eyepieces that have a long working distance to accommodate the thickness of the dish.
optical system
Resolving power is the ability to see sample details and the speed at which images can be resolved—another important factor to consider.
“Objectives are critical in an optical system,” emphasizes Jeff McGinn, president of McCrone Microscopy and Accessories, an instrumentation division of the McCrone Group. “The higher the numerical aperture (NA) of an objective, the better its resolving power. We evaluate the level of detail the user needs to see and budget, to help users choose an objective lens with a suitable numerical aperture (NA). "In addition to numerical aperture (NA), it is also necessary to evaluate the degree of correction of spherical aberration and chromatic aberration of the microscope objective lens.
In terms of budget, Alvarenga advises: “Choose an objective within your budget. The quality of the objective will directly affect the quality of the data, so this is a very important factor to consider.” You can also choose objectives designed for specific techniques, such as phase contrast Imaging, silicone optical time-lapse imaging. Phase contrast imaging is commonly used in wet laboratories, especially those performing cell counts or viability assays. At the same time, check the working distance of the objective lens (that is, WD, the distance between the lens and the sample) to determine whether it matches your sample type.
detection
Another important part of the microscope light path is the acquisition device for the sample signal.
"Camera technology is developing rapidly," Olenych said, noting that demand for CMOS camera chips is increasing rapidly compared to traditional CCD technology. CMOS chips are usually larger in size and more sensitive than CCD chips, he explained. CMOS chips have more pixels, which means that they can achieve finer imaging in a smaller area. Photomultiplier tubes (PMTs) are also an option in applications that do not require spatial resolution. PMTs do not store charge and can respond to changes in incoming light flux within nanoseconds, so they are used to detect and record extremely fast events.
ease of use
Another factor that may influence your decision is the ease of use of the microscope system. The user-friendliness of an instrument depends largely on the software's interface. "Olympus software is very common across all systems under its brand, reducing the time to re-explore methods on a new microscope system and to train new lab personnel," Alvarenga said. Some microscope developers have introduced more intuitive interfaces, controlling the instrument through touchscreen technology. For example, the Revolve microscope from Echo Laboratories is controlled by an App under the iOS system, which has a pinch-to-zoom function, and can also perform cell counts by clicking the screen. Eugene Cho, CEO and Founder of Echo Laboratories, explained: “Ease of use, which used to be of the least concern to the user, is becoming more and more important to the user.
