Improved Western blot detection using CCD digital imaging: Comparison of cooled-CCD digital imaging versus X-ray film

Chemiluminescent Western blotting is a popular protein detection method for studying proteins. The typical protocol for measuring chemiluminescent signal exposes the Western blot to laboratory-grade X-ray film, but digital imaging using a cooled-CCD camera is proving to be a more functional choice for researchers. The Thermo Scientific MYECL Imager offers digital imaging with a number of improvements over film detection, including greater signal sensitivity, linearity and dynamic range. Introduction Western blot analysis has been used as a qualitative assessment of the presence of a specific protein of interest in a sample with a target-specific antibody. Relative differences in protein amounts can be assessed by the signal intensity as it typically correlates to the protein amount in the blot. Scanning of the film with a basic document scanner and the use of image analysis software has been used to extract some quantitative information; however, densitometry from the scanned X-ray film image can be challenging and chemiluminescent Western blot analysis is generally regarded as not being quantitative. An alternative method to X-ray film for capturing luminescent signals from Western blots is to use a cooledCCD camera. Charge-coupled device (CCD) cameras use a light-sensitive silicon chip that converts photons into digital signals. Imagers with early generation CCD cameras designed for low-light applications were not capable of matching the speed or sensitivity of X-ray film.