Imaging Systems

Imaging Systems

Bio-Rad's family of imaging systems.

The selection of which image acquisition device to use for the digitization of electrophoresis gels depends on the staining technique used (see Table below):

• Densitometers — based on high-performance document scanners utilizing visible light for analysis of electrophoresis gels and blots stained with visible dyes. Bios-Rad' GS-800™ calibrated densitometer can be used to image both gels and blots and has a linear response up to 3.0 optical units in gray levels
  

  GS-800 calibrated densitometer.

• Charge-Coupled Device (CCD) cameras — operate with either trans-illumination provided by UV or visible light boxes positioned underneath the gel or blot for imaging a variety of stains (Coomassie, silver, fluorescence) or epi-illumination detected using colormetric or fluorescent techniques. Supercooled CCD cameras reduce image noise, allowing detection of faint luminescent signals. Bio-Rad's Gel Doc™ EZ system provides four application-specific trays: a UV tray (for ethidium bromide staining of DNA gels and fluorescence imaging), a white tray (for Coomassie, copper, silver, and zinc stains), a blue tray (for nondestructive nucleic acid imaging), and a Stain-Free tray for direct visualization, analysis, and documentation of protein samples in polyacrylamide gels without staining, destaining, or gel drying (see sidebar). Bio-Rad's ChemiDoc MP system has the ability to image colorimetric and fluorescently stained gels and blots to detect chemiluminescent and other low light and multiplex or multiplex fluorescent samples
  
  

  Gel Doc EZ system	Gel Doc XR+ system	ChemiDoc XRS+ system	ChemiDoc MP system

• Laser-based scanners — offer the highest sensitivity, resolution, and linear dynamic range. They are powerful image acquisition tools for electrophoresis gels and blots stained with fluorescent dyes like Flamingo™ fluorescent gel stain. Lasers can be matched to the excitation wavelengths of a multitude of fluorophores. Bio-Rad's PharosFX™ systems use multiple lasers, which enhance application flexibility and allow optimal excitation of single and multicolor fluorescent samples to enable detection of almost any fluorescent dye or label
  

  PharosFX™ system	PMI™ system

Imaging System Selection Guide.

— Not recommended; 1–5, recommendation level (5 = highest).
* Optimal with low fluorescence PVDF membrane.
** With spot diameters >400 µm.