Splette, Wikimedia Commons, 2006

Advance in the recording of samples by fluorescence microscopes

04. 05. 2015

Fluorescence microscopes have been finding ever wider application in the natural sciences and medicine. Researchers at Brno University of Technology have invented a method of how to combine on the microscope bright field and fluorescence measurement and to use this method when monitoring the physiological functions of heart cells.

The phenomenon called fluorescence is often used in the sophisticated imaging of both organic and inorganic structures or for observing cell processes. When the fluorescent dye receives radiation in the fields of shorter wavelengths of UV or visible light, in which it is able to absorb exciting radiation, it emits its own radiation. For observing this radiation, fluorescence microscopes and highly sensitive and very fast fluorescence cameras are used. Fluorescence is often used in cardiology research for observing concentrations of intracellular calcium, which is otherwise difficult to achieve. The dynamics of the concentration of intracellular calcium is closely related to the mechanical contractions of cardiac muscle cells; however, these are watched in the bright field of a microscope.

Modern microscopy enables measurement using two or more fluorescent dyes, mostly using a rotating filter changer (wheel). In this way, scientists can observe the differently dyed structures. If the shape of the object being examined is to be evaluated, imaging in the bright field must be provided. Without the option of gradually switching channels this is difficult, since strong passing light degrades weak fluorescence. Moreover, the observed phenomena are very fast and a time delay due to switching between channels is unacceptable.

Researchers at the Brno University of Technology, Ing. Vratislav Čmiel and Prof. Ing. Ivo Provazník, Ph.D. of the Department of Biomedical Engineering at the Faculty of Electrical Engineering and Communication have come up with a technical solution in the form of an adapter intended for connecting to fluorescence microscopes. The adapter enables the image of observed cells to be divided spectrally into two digital cameras, and at the same time it captures the spectrally divided image without any time delay.

The structural design of the invention offers other advantages. It contains only one optical filter, placed along with a dichroic mirror at the output. Consequently, with the adapter on the microscope the observed samples lose almost none of the intensity of fluorescence. When combining fluorescent imaging with imaging in the bright field, the insertion of another filter into the optical path of the passing light source will suffice.

Dynamic calcium manifestations can be measured using a calcium indicator along with heart cell contractions in the observed heart cells. Multi-channel fluorescence microscopic measurement is generally used in various fields of cell biology and medicine. The invention is also expected to find its use in other fields. Support for such expectation comes in part from the high variability of the adapter and the magnetic holding of the fluorescent cube, enabling easy and quick filter exchange.

The device is protected by:

Author: Ing. Vratislav Čmiel

Source of initial picture: Splette, Wikimedia Commons, 2006


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