Fluorescence Western Blot Imaging System

What is the Fluorescence Western Blot Imaging System?

This system excites fluorescently labelled antibodies on a blot and captures two or more channels in one image, allowing multiplex detection and total protein normalization. It suits laboratories that need to compare several targets on the same membrane without stripping and reprobing.

Overview

Fluorescent conjugates with distinct excitation and emission spectra are applied simultaneously or sequentially, and the instrument images the membrane at each channel's wavelengths using LED or laser excitation and matched filters. Because the signals are spectrally separated, two or more targets can be measured on the same blot, and a total protein channel can serve as the loading control instead of a single housekeeping band. Sensitivity depends on the fluorophore, the conjugate quality and the background autofluorescence of the membrane, so low-fluorescence membranes and appropriate blocking reagents are usually specified. The system also supports multiplex diagnostic blots with different labels, and quantitative output requires channel-specific calibration and careful avoidance of signal bleed-through between channels.

How does it work?

Immunoblotting starts with proteins that are either separated by polyacrylamide gel electrophoresis and transferred to a membrane, or applied directly as discrete lines on a strip. The membrane is blocked to prevent non-specific binding, then incubated with diluted patient sample so that antibodies in the sample bind to their target antigens. After washing, an enzyme- or fluorophore-labelled anti-human antibody is added, and a substrate produces a visible, luminescent or fluorescent signal proportional to the bound antibody. Strips are read by eye, by a scanning densitometer or by a charge-coupled device camera, and each band is scored as absent, weak, moderate or strong, or quantified as an intensity ratio against a control band. Interpretation criteria for confirmatory assays are set by the manufacturer and by national guidance, and the pattern of reactive bands, not a single band, determines the reported result.

What are the key features?

• LED or laser excitation with matched emission filters
• Simultaneous two or more channel acquisition
• Total protein channel as a loading control
• Low autofluorescence membrane compatibility
• Multiplex diagnostic blot support
• Channel-specific calibration to limit bleed-through

What are the technical specifications?

A typical fluorescence western blot imaging system configuration offers excitation sources of LED or laser at 488, 532, 635 and 685 nm, emission filters of 4–6 bandpass filters, 520–800 nm, channels of Two-colour or four-colour simultaneous imaging, detector of Cooled CCD or complementary metal oxide sensor, membrane sizes of Up to 10 × 15 cm and sensitivity of Low nanogram to picogram range per band depending on the label. 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 Fluorescence Western Blot Imaging System is used in multiplex protein expression studies, diagnostic blot confirmation with internal controls, autoimmune antigen multiplex blots and research requiring total protein normalization. Across the wider Immunoblot Systems class, laboratories also deploy it for HIV and hepatitis confirmatory testing, autoimmune antibody profile testing and lyme disease and syphilis confirmation.

Which standards and certifications apply?

Relevant standards and methods include ISO 15189, CLSI M53, CLSI EP05, CLSI EP17, WHO HIV testing strategy, IEC 61010-1 and IEC 61010-2-101. Certification candidates for this model are CE, ISO 13485 manufacturing and NMPA registration for research use; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Work on a clean bench with gloves, since membranes are easily contaminated, and use only the buffers and dilutions specified in the kit, because salt concentration and pH change binding and washing efficiency. Keep incubation temperatures and times consistent, as band intensity varies with both, and avoid letting strips dry out between steps. Verify performance at installation with the kit's positive and negative controls and with a proficiency panel if available, and repeat the check with each new reagent lot. Clean the scanner or imaging optics regularly, keep the light source stable for fluorescence and luminescence work, and store images together with the patient identifier for the retention period required by local rules.

How do I select the right Fluorescence Western Blot Imaging System?

Specify this system when two or more targets must be measured on one membrane, when a total protein channel replaces a single loading control, or when diagnostic blots carry internal labelled controls. In the RFQ confirm channel separation performance, the membrane and blocking reagents recommended to keep autofluorescence low, and the software's normalization workflow.

How does it compare with other Immunoblot Systems variants?

Decide first whether the laboratory processes strips manually or needs automated incubation and washing, because the processing step dominates hands-on time and reproducibility. Then choose the reading method: visual reading suits low volumes and is accepted for many line immunoassays, densitometry provides objective band intensity, and camera-based imaging supports chemiluminescence and multiplex fluorescence. Check that the instrument accepts the strip and membrane formats of your kits, that the software applies the manufacturer interpretation criteria, and that images and results are archived in a retrievable format. Confirm assay registration in your market, and the availability of controls, conjugates and substrates, since these consumables are kit specific and may have short shelf lives.