PH-controlled release of substrates from mesoporous SiO2 nanoparticles gated by metal ion-dependent DNAzymes

Zhanxia Zhang, Fuan Wang, Dora Balogh, Itamar Willner*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

The pH-controlled release of substrates from mesoporous SiO2 nanoparticles, MP-SiO2 NPs, is demonstrated by capping the pores with the Mg2+- or UO22+-dependent DNAzyme sequences and unlocking of the pores with Mg2+ ions or UO2 2+ ions at appropriate pH values. While the Mg2+-dependent DNAzyme reveals high activity at pH = 7.2, moderate activity at pH = 6.0, and it lacks activity at pH = 5.2, the UO22+-dependent DNAzyme reveals high activity at pH = 5.2, moderate activity at pH = 6.0, and it is catalytically inactive at pH = 7.2. Accordingly, the MP-SiO2 NPs were loaded with methylene blue, MB+, or thionine, Th+, and locked in the pores by the Mg2+- and UO2 2+-dependent DNAzyme sequences, respectively. The pH-programmed release of MB+ or Th+ from the loaded NPs proceeds, in the presence of Mg2+ ions or UO22+ ions, at pH = 7.2 and pH = 5.2, using the Mg2+- and UO2 2+-dependent DNAzyme as catalysts that cleave the protecting caps and unlock the pores, respectively. At pH = 6.0 the MB+- and Th +-loaded NPs are concomitantly unlocked by the two DNAzymes. The unlocking processes are selective and other metal ions do not stimulate the release processes. This journal is

Original languageEnglish
Pages (from-to)4449-4455
Number of pages7
JournalJournal of Materials Chemistry B
Volume2
Issue number28
DOIs
StatePublished - 28 Jul 2014

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