Probe composition print buffer

Perhaps the least rmderstood factor in the process of microarraying is the print buffer (probe ink) composition. This may not be too much of a surprise because manufacturers of computer printers offer consumers a multitude of different inks (whose formulas are closely guarded trade secrets) for use with a particular printer and kind of paper. In fact, it can be argued that the ink is perhaps the most important piece of the consumable product stream for this manufacturing sector. 

consider oligonucleotide structure. Unmodified nucleic acid probes may be viewed as negatively charged polymers (they are polyanions) 

The ink is composed of the probe, buffer, and most often a wetting agent that allows uniform deposition of the oligonucleotide to the substrate surface to control spot size and spot morphology. Other additives to the ink may be present to prevent or slow evaporation in an effort to control spot size. Fluorescent or other dye stuffs are sometimes included to monitor prinhng efficiency. The ink can therefore represent a complex matrix for the probe. 

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There are many approaches by which to prepare a probe for immobilization to a substrate by printing. The exact nature of the buffer (ink) composition will depend upon the surface characteristics of the substrate and the surface... 

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