The UVITec crosslinker is a convenient tool for delivering controlled amounts of ultraviolet irradiation. We have used the device successfully for crosslinking DNA and oligonucleotides to glass slides for microarrays as well as crosslinking nucleic acids to membranes for colony hybridization, Southern blotting and Northern blotting.
One of the main benefits of this unit is its size. It is a small, fully enclosed system that allows UV exposure to the nucleic acid and solid support without the need for a darkroom. Of course, the machine also accurately determines the energy applied using a photocell-based feedback mechanism. This is difficult or impossible using a standard UV transilluminator (the energy output from UV emission tubes decreases with age). The energy output can be controlled by setting the irradiation time (minutes) or energy output (joules). Strangely, some of the units measure in minutes and tenths of minutes, rather than minutes and seconds. The newer models measure in minutes and seconds.
The unit is available in three different wavelengths; 254 nm, 312 nm or 365 nm. The wavelength can be changed at any time by replacing the UV emission tubes inside the unit. We have found that replacement is relatively inexpensive and easy, as the instrument uses 5 x 8 W fluorescent type tubes.
The door of this unit has a safety interlock to prevent accidental UV exposure to the people operating the unit. The unit will continue the irradiation without losing its settings when the door is closed again. However, the safety interlock takes longer to deactivate the UV source than other units that we have tested (although the time of radiation leakage is short, only one or two seconds). The unit also has a viewing window which is transparent, but protected from UV light. This means that the solid support can be observed during irradiation, unlike many other brands of crosslinkers. We have found this feature useful for membranes that are likely to dry out or curl.