Spotting DNA at a high resolution for microarray fabrication

A Microplotter was used to deposit ~35 micron spots of a DNA solution on a chemically treated glass slide to fabricate a one-component microarray. A fluorescently-labeled oligonucleotide solution was loaded into a Microplotter and dispensed in a complex pattern on a treated surface. The oligonucleotides had been modified with an amine group, which reacted with the epoxide chemical groups on the surface of the glass slide and covalently bound the oligonucleotides to the surface.

Traditional microarray spotting systems deposit spots with diameters in the range of 75-150 microns, so the ability to print 35-micron-wide features (with a lower limit of 5 microns in width) leads to a significant increase in microarray density. The features were also very regular in shape and size, with coefficients of variability of less than 10% for spot diameter.