Expression profiling by oligonucleotide microarrays spotted on coated polymer slides

We have developed a ready-to-spot polymer microarray slide, which is coated with a uniform layer of reactive electrophilic groups using anthraquinone-mediated photo-coupling chemistry. The slide coating reduces the hydrophobicity of the native polymer significantly, thereby enabling robust and efficient one-step coupling of spotted 5' amino-linked oligonucleotides onto the polymer slide. The utility of the coated polymer slide in gene expression profiling was assessed by fabrication of spotted oligonucleotide microarrays using a collection of 5' amino-linked 70-mer oligonucleotide probes representing 96 yeast genes from Operon. Two-colour hybridizations with labelled cDNA target pools derived from standard grown and heat-shocked wild type yeast cells could reproducibly measure heat shock induced expression of seven different heat shock protein (HSP) genes. Moreover, the observed fold changes were comparable to those reported previously using spotted cDNA arrays and high-density 25-mer oligonucleotide arrays from Affymetrix. The low hybridization signals obtained from the DeltaSSA4 mutant cDNA target, together with the high signal detected in two-colour hybridizations with heat-shocked wild type yeast relative to the DeltaSSA4 mutant strain implies that unspecific binding of cDNA target to the SSA4-specific 70-mer oligonucleotide probes is negligible. Combined, our results indicate that the coated polymer microarray slide represents a robust and cost-effective array platform for pre-spotted oligonucleotide arrays.