AbstractThe fabrication of DNA arrays directly on aminolyzed sheets of poly(ethylene terephthalate) (PET) is described. Array surfaces typically employ bifunctional linkers or layers of covalently attached polymers to provide substrate hydroxy groups as synthesis attachment points. An amine treatment is used here to expose hydroxy groups on films of PET. These hydroxy groups can then be used to couple phosphoramidites and initiate the array synthesis without further functionalization steps. Arrays fabricated on these substrates with a maskless array synthesizer are tolerant of the high number of chemical exposure steps required to synthesize relatively long oligonucleotides. The results might be of the greatest use to the synthetic biology community, for whom a flexible and robust substrate could enable new strategies to enhance the throughput of oligonucleotide synthesis.