A flexible light-directed DNA chip synthesis gated by deprotection using solution photogenerated acids

Oligonucleotide microarrays or oDNA chips are effective decoding and analyt ical tools for genomic sequences and are useful for a broad range of applic ations. Therefore, it is desirable to have synthesis methods of DNA chips t hat are highly flexible in sequence design and provide high quality and gen eral adoptability. We report herein, DNA microarray synthesis based on a fl exible biochip method. Our method simply uses photogenerated acid (PGA) in solution to trigger deprotection of the 5'-OH group in conventional nucleot ide phosphoramidite monomers (i.e. PGA-gated deprotection), with the rest o f the reactions in the synthesis cycle the same as those used for routine s ynthesis of oligonucleotides. The complete DNA chip synthesis process is ac complished on a regular DNA synthesizer that is coupled with a UV-VIS proje ction display unit for performing digital photolithography. Using this meth od, oDNA chips containing probes of newly discovered genes can be quickly a nd easily synthesized at high yields in a conventional laboratory setting. Furthermore, the PGA-gated chemistry should be applicable to microarray syn theses of a variety of combinatorial molecules, such as peptides and organi c molecules.