Next-Gen Photonics Instruments OPTICAL PRODUCT components within complex biological systems has transformed our understanding of cellular function, disease mechanisms, and developmental biology. Light sources are a critical component of fluorescence microscopy, as they provide the excitation energy required to stimulate fluorophores and generate the emitted fluorescence signal. The choice of light source directly influences the brightness, resolution, and sensitivity of the imaging system. Modern fluorescence microscopes increasingly use LEDs as light sources due to their long lifetimes, low power consumption, and rapid switching between wavelengths, making them ideal for routine and multi-color imaging. Compared to mercury and metal halide lamps traditionally used for widefield fluorescence, LEDs offer many advantages for automated systems. The UK based company CoolLED designs and manufactures cutting-edge LED illumination systems for these applications. They have developed powerful, stable and customisable multi-spectral solutions for manufacturers of automated fluorescence systems. Their ultra-bright illumination with high-speed TTL triggering increases imaging speed, boosting throughput which is especially valuable for high-content screening. Slide scanning also benefits where homogeneous illumination is critical for high-quality image stitching, so image acquisition is both fast and high quality. The need for deeper tissue penetration, reduced background autofluorescence and improved photostability has driven the development of fluorescent dyes in the red to nearinfrared( NIR) spectral region. Some examples are the stabilized boreniumion dye, which emits in the red / NIR region and remains stable in air, or the optimized redabsorbing rhodamine derivatives, which can improve brightness and spectral tuning in the red region. For these new
Figure 1: Cell confluence measurement. Left, raw image from the incubator; right, AI processed false color image( Source: Opto GmbH).
dyes, the wavelengths range 340-850 nm of the CoolLED’ s solutions allows them to cover the full range of fluorophore needs.
THE ROLE OF CALIBRATION TARGETS High-end fluorescence microscopes often require the use of calibration targets for reproducible x / y / z positioning and sensitivity. They are essential tools for ensuring the accuracy, consistency, and reproducibility of imaging data across different instruments and serve as reference standards to assess key imaging parameters such as spatial resolution, intensity uniformity, spectral alignment, and chromatic aberration. As fluorescence microscopy becomes more complex, reliable calibration becomes increasingly critical for validating results and meeting rigorous standards in different biomedical applications.
Figure 2: LED source for fluorescence microscopy( Source: CoolLED).©
Calibration targets traditionally consisted of reservoirs of fluorescent liquids, doped specialty glass or colored beads. The recent developments in broadband photoluminescent coatings have shown very interesting advantages. These engineered thin-film or substrate-embedded materials are particularly valuable for validating system performance, because a single target can generate a stable, broad-range fluorescence output under multiple excitation wavelengths. The company IMT Masken und Teilungen AG, with extensive experience in building sub-micron patterning processes, has developed cost-effective solutions to meet specific users’ requirements for photoluminescent patterns on glass. In collaboration with the Swiss Federal Laboratories for Materials Science and Technology( Empa), broadband photo-luminescent coatings have been developed and optimized for use in various application scenarios. These include plasma-deposited inorganic thinfilm coatings with high resistance to radiative degradation for high-power illumination, as well as bright photoluminescent organic-based coatings. The susceptibility of the coatings to bleaching has been further reduced by applying additional layers of heat dissipating material. IMT has optimized the processes for depositing photoluminescent layers as well as the nanopatterning processes, to coat arbitrary and large area structures.
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