Imaging electrophoretic gels with a scanning beam laser macroscope

A scanning beam laser macroscope has been developed which scans an area of 7.5 × 7.5 cm in 5 s. This new imaging system is examined as a potential tool for scanning electrophoretic gels. A specially‐designed telecentric, ƒ*θ laser scan lens is used in the instrument to achieve a linear scan and a flat focal plane. The laser scan lens focuses the incoming beam from a laser to a 10 μm spot inside the gel. A raster scan is performed across the gel and the signal is detected with a photomultiplier, forming a 512 × 512 digital image stored as a computer file. Silver‐stained protein polyacrylamide gels have been imaged in transmission and double‐transmission, while DNA agarose gels (stained with ethidium bromide) have been imaged in fluorescence with better than 25 pg. sensitivity. The macroscope has the advantage that it is not tied to the electrophoresis system as are end‐of‐line scanners, and the scan is rapid, so that several gels can be scanned in a very short time.