DNA self-polymers as microarray probes improve assay sensitivity

We have developed a novel microarray probe with increased sensitivity. In this approach, PCR-generated microarray probes are end-ligated into redundant polymers and printed on standard arraying surfaces. These DNA polymer probes result in greatly improved sensitivity over classical monomer probes. Furthermore, polymer microarray sensitivity can be even further improved by incorporation of a biotin adapter into the first strand cDNA during reverse transcription and attachment of a gold particle (Genicon RLS, Invitrogen, CA) in a secondary reaction. This approach allowed us to reliably assess: expression of genes from <5 μg of total RNA starting material without sample amplification. Finally, the resonance light scattering-labeled microarrays can be archived without fading, allowing re-scanning at a later time.