Homemade microarrays are made by printing or arraying nucleic acids (the “microarray probes”) onto pre-treated glass microscope slides. The microarray probes can either be cDNAs or oligonucleotides. To manufacture cDNA probes, cDNA clone collections are amplified by polymerase chain reaction (PCR). For oligonucleotide probes, 50-70mer oligos are ordered from a commercial vendor.
The probes are printed in a two-dimensional grid onto
glass. Spots are
typically 100–300 µm in size and are spaced about the same distance
apart. Using this technique, arrays consisting of more than 25,000 cDNAs
or oligonucleotides can be printed onto the surface of a conventional microscope