Enzyme-responsive snap-top covered silica nanocontainers

Kaushik Patel, Sarah Angelos, William R. Dichtel, Ali Coskun, Ying Wei Yang, Jeffrey I. Zink*, J. Fraser Stoddart

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

542 Scopus citations


Mesoporous silica nanoparticles, capable of storing a payload of small molecules and releasing it following specific catalytic activation by an esterase, have been designed and fabricated. The storage and release of the payload is controlled by the presence of [2]rotaxanes, which consist of tri(ethylene glycol) chains threaded by α-cyclodextrin tori, located on the surfaces of the nanoparticles and terminated by a large stoppering group. These modified silica nanoparticles are capable of encapsulating guest molecules when the [2]rotaxanes are present. The bulky stoppers, which serve to hold the tori in place, are stable under physiological conditions but are cleaved by the catalytic action of an enzyme, causing dethreading of the tori and release of the guest molecules from the pores of the nanoparticles. These snap-top covered silica nanocontainers (SCSNs) are prepared by a modular synthetic method, in which the stoppering unit, incorporated in the final step of the synthesis, may be changed at will to target the response of the system to any of a number of hydrolytic enzymes. Here, the design, synthesis, and operation of model SCSNs that open in the presence of porcine liver esterase (PLE) are reported. The empty pores of the silica nanoparticles were loaded with luminescent dye molecules (rhodamine B), and stoppering units that incorporate adamantyl ester moieties were then attached in the presence of α-cyclodextrin using the copper-catalyzed azide-alkyne cycloaddition (CuAAC), closing the SCSNs. The release of rhodamine-B from the pores of theSCSN, following PLE-mediated hydrolysis of the stoppers, was monitored using fluorescence spectroscopy.

Original languageEnglish (US)
Pages (from-to)2382-2383
Number of pages2
JournalJournal of the American Chemical Society
Issue number8
StatePublished - Feb 27 2008

ASJC Scopus subject areas

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry


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