Multispectral Fluorescence Imaging System

What is the Multispectral Fluorescence Imaging System?

A multispectral fluorescence imaging system captures the emission spectrum at each pixel and separates overlapping signals computationally, allowing five or more targets to be resolved on one blot or tissue section with reduced autofluorescence interference.

Overview

Instead of using a single bandpass filter per dye, a multispectral system acquires a series of images across narrow wavelength bands or the full emission range. Because each fluorophore has a characteristic spectrum and autofluorescence has its own, linear unmixing can separate the contributions of each component even when their emission peaks overlap. This allows panels of five to seven labelled antibodies to be used on the same membrane or section, and it removes background from membrane or tissue autofluorescence that would otherwise hide weak bands. Sensitivity depends on the quantum efficiency of the detector at each wavelength, and unmixing requires accurate reference spectra recorded from single-colour controls. The approach is widely used for multiplexed immunohistochemistry and for quantitative multiplexed blotting.

How does it work?

Imaging systems convert a signal on a membrane or gel surface into a calibrated digital image. In chemiluminescence imaging, no excitation light is needed: an enzyme such as horseradish peroxidase converts a substrate into an excited product that emits light, and a cooled CCD or CMOS sensor integrates that faint emission over minutes. Fluorescence imaging instead excites fluorophores with LEDs or lasers and collects emitted light through bandpass filters, which allows multiplexing with differently labelled antibodies. Colorimetric systems use white or coloured illumination and measure transmitted or reflected light to quantify stained bands such as Coomassie blue. Laser scanning instruments move a focused beam across the surface and record point by point, which gives high spatial resolution and a wide linear dynamic range. In all cases the software subtracts background, converts pixel intensities to optical density, and compares bands with a standard or loading control.

What are the key features?

• Spectrum acquisition across narrow bands or full emission range
• Linear unmixing resolves overlapping fluorophore signals
• Panels of five to seven labelled targets per sample
• Removal of membrane or tissue autofluorescence background
• Reference spectra captured from single-colour controls
• Quantitative analysis with per-channel intensity tables

What are the technical specifications?

A typical multispectral fluorescence imaging system configuration offers spectral channels of 8–32 narrow bands or continuous spectral scan, wavelength range of approx. 400–900 nm, multiplex capacity of 5–7 targets per sample (dye dependent), excitation sources of LED or laser lines, 4–8 selectable, detector of Cooled CCD or sCMOS and unmixing of Linear unmixing from single-colour reference spectra. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Multispectral Fluorescence Imaging System is used in multiplexed quantitative western blotting, multiplexed immunohistochemistry imaging, autofluorescence removal in tissue sections and co-localisation studies with several markers. Across the wider Protein Imaging class, laboratories also deploy it for western blot band quantification, protein purity assessment from stained gels and multiplexed fluorescence immunodetection.

Which standards and certifications apply?

Relevant standards and methods include USP <1057>, Ph. Eur. 2.2.31, IEC 61010-1, ISO 17025, 21 CFR Part 11 and ISO 9001. Certification candidates for this model are CE, ISO 9001 manufacturing and IEC 61010-1 safety; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Keep the imaging area clean and free of dust, because particles scatter light and appear as false bands. Avoid saturating the sensor, since saturated pixels cannot be used for quantification; most software flags them, and exposure series should be used to confirm the signal is in the linear range. Chemiluminescent substrates decay within minutes to an hour, so imaging should follow the supplier's timing recommendation and be consistent between samples. Fluorescent blots fade with repeated exposure, so images should be captured once where possible. Calibrate the instrument periodically with a step tablet or fluorescence standard and record the settings used, so that images from different sessions remain comparable. Archive raw files, not only processed figures, because quantitative results may need re-analysis.

How do I select the right Multispectral Fluorescence Imaging System?

Select a multispectral system when more than three targets must be measured together or when autofluorescence interferes with weak signals. Specify spectral channel count and range, excitation options, multiplex capacity, unmixing software and the reference-spectrum workflow it requires.

How does it compare with other Protein Imaging variants?

Choose the detector that matches your detection chemistry. Chemiluminescence needs a cooled sensor with low dark current and long integration times, and absolute sensitivity matters more than resolution. Fluorescence needs matched excitation sources and emission filters, and filter selection should cover the dyes you actually use, including near-infrared pairs for low-background multiplexing. Colorimetric and densitometry work needs uniform illumination and colour calibration to make Coomassie or silver staining quantitative. Laser scanning suits applications where a wide linear dynamic range and high resolution are essential, such as purity determination with small impurity peaks. Check the camera or scanner resolution in millimetres per pixel, dynamic range in orders of magnitude, cooling temperature, imaging area, light source lifetime and whether the software supports background subtraction, saturation warnings, lane profiling and export of numerical data.