Bacteria on the spot ! - (May/24/2006 )

Hello friends !

I am a novice to microarrays.

I have learnt that typical DNA or PROTEIN ayyar spots are around the size of 100 um (approxamately) and the center-to-center distance between two spots is around 140 um.
The size of the spots are quite large as compared to the average size of most bacteria.
In such a case, a few bacterial cells can be easily accomadated in the area of SAY a Protein spot.
My question is that how are these spots(slides) protected from contamination as the bacteria can easily degrade the protein molecules, not only during manufacturing but during actual use of the slides in labs? I have seen people working with microarray slides without any special asceptic hoods and other such measures.

The question may seem very stupid to experts but kindly help answering !

Thank you very much.

I'd suggest taking an array (or a plain glass slide), putting it under a microscope, and trying to see some bacteria. There aren't any. Sure, there will be one or two, perhaps, but bacteria like moist, food-rich environments, totally unlike the surface of a glass slide with chemicals on it. Unless you store your arrays moist in an incubator, you have little to worry about.

From a commercial aspect, we usually add a preservative to our solutions. That way, we stop any bugs before they get a hold. And as phage said, the slide is dry, so bugs won't be able to do much anyway.