Flow cytometry

Counting blood cells

Thousands of cells per second are counted and characterized in medical and biotechnical analytics with laser-based flow cytometry. This enables the fast and secure detection of blood anomalies.

 

Flow cytometer principle

Simultaneous multi-wavelength detection

Flow cytometry is widely used in diagnosis of health disorders, especially blood cancers, but has many other applications in basic research, clinical practice and clinical trials. It relies on the detection of fluorescence signals that are 1000 times weaker than scattered light, which in turn is 1000 times weaker than the light that the sample is illuminated with. Alas, the task in flow cytometry is to detect a signal that is a million times weaker than the illumination light. This fact explains the high requirements to filters and dichroic beamsplitters that are used in flow cytometry. For a detailed description of flow cytometry please refer to BD's excellent Flow Cytometry Web-Based Training or Oregon State Univerity's equally valuable resource Flow Cytometry - How Does It Work?

 

 

 

Separating absorption and emission spectra

Absorption and emission spectra of most fluorophores (fluorescent dyes) are closely located and often even overlap. This requires that excitation and emission filters have very steep edges to effectively separate absorption and emission peaks from each other. High out-of-band rejection is essential to make the the weak fluorescence signal detectable among the strong illumination light. Well designed dichroic beamsplitters have broad reflection and transmission wavelength ranges with a sharp transition in between. They help suppressing the excitation light by at least two orders of magnitude and allow contrast rich imaging of cells and other specimens.

Decades of experience with fluorescence filters

Did you know that Delta Optical Thin Film was the first to suggest the use of interference filters to Carl Zeiss and Leica in the late 1960s? We started volume manufacturing of fluorescence filters in the early 1970s and were the first to implement computer controlled deposition in the early 1990s. Using our own synthesis and deposition control software allows us to offer coatings made with plasma assisted e-beam evaporation technology with a quality equal to that achievable by IBS and similar technologies. With our decades of experience we are today the biggest supplier of high performance fluorescence filter sets to the market leading manufactures of fluorescence microscopes.

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