A laser scanner for imaging fluorophore labeled molecules in electrophoretic gels

Abstract

A laser scanner for imaging electrophoretic gels was constructed and tested. The scanner incorporates a green helium-neon (HeNe) laser (543.5nm wavelength) and can achieve a spatial resolution of 1 9~. The instrument can function in two modes : "snap-shot" and "finish-line". In snapshot mode, all samples are electrophoresed for the same time and the gel is scanned after completion of electrophoresis, while in finish-line mode, fluorophore labeled samples are electrophoresed for a constant distance and the image is formed as the samples pass under the detector. The resolving power of the fkh-line mode of imaging is found to be greater than that of the snapshot mode of imaging. This laser scanner is also compared with a Charge Coupled Device (CCD) camera and in terms of resolving power is found to be superior. Sensitivity of the instrument is presented in terms of the mi ni mum amount of DNA that can be detected verses its molecular length.

A Comparison of Electrophoretic Resolution for Snapshot and Finish-Line Imaging

“…3 using the same charge-coupled device imaging system used in Ref. (5) and found that of the resolving power provided by finish-line imaging compared to that of snapshot imaging continues to im-resolving power was lower than that obtained with our laser scanner in either mode (18). This difference in prove for all of the molecular lengths that we studied, the absolute values of resolving power for each method resolving power is not due to any inherent deficiency in the optics of the charge-coupled device system, howpeak between 2 and 3 kbp and decline thereafter.…”