Cló, E.; Snyder, J. W.; Voigt, N. V.; Ogilby, P. R.; Gothelf, K. V.
J. Am. Chem. Soc. 2006, 128, 4200–4201, doi: 10.1021/ja058713a
Department of Chemistry, University of Aarhus, Langelandsgade 140, 8000 Århus C, Denmark
DNA sequence-controlled on-and-off switching of a singlet oxygen sensitizer has been developed and demonstrated. The singlet oxygen photosensitizer pyropheophorbide-a (P) was attached to a 15-mer nucleotide sequence. A molecule that could quench the sensitizer, the so-called “black hole quencher 3” (Q), was attached to a complementary nucleotide strand. Upon hybridization of the two conjugates, singlet oxygen production from P was completely shut down. Upon the addition of a third DNA sequence that can displace and release the P−DNA conjugate from the P−Q pair, up to 85% of the singlet oxygen production was recovered. This system is a model for a benign drug that becomes active only in the presence of a specific targeted nucleotide sequence.