1. Academic Validation
  2. Single and Bilayer Polyacrylamide Hydrogel-Based Microcapsules for the Triggered Release of Loads, Logic Gate Operations, and Intercommunication between Microcapsules

Single and Bilayer Polyacrylamide Hydrogel-Based Microcapsules for the Triggered Release of Loads, Logic Gate Operations, and Intercommunication between Microcapsules

  • ACS Appl Mater Interfaces. 2020 Jul 15;12(28):31124-31136. doi: 10.1021/acsami.0c06711.
Sivan Lilienthal 1 Amit Fischer 1 Wei-Ching Liao 1 Remi Cazelles 1 Itamar Willner 1
Affiliations

Affiliation

  • 1 Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Abstract

A method to assemble loaded stimuli-responsive DNA-polyacrylamide hydrogel-stabilized microcapsules is presented. The method involves coating substrate-loaded CaCO3 microparticles, functionalized with nucleic acid promoter units, and cross-linking DNA-modified polyacrylamide chains on the microcapsules, using the hybridization chain reaction (HCR) to yield the DNA-cross-linked hydrogel coating. Dissolution of the CaCO3 particles generated the substrate-loaded hydrogel-protected microcapsules. The microcapsule-hydrogel shells include engineered stimuli-responsive oligonucleotide cross-linkers that control the stiffness of the hydrogel shells, allowing the triggered release of the loads. One approach includes the incorporation of cofactor-dependent DNAzyme units into the cross-linked hydrogel layers (cofactor = Mg2+ ions, Zn2+ ions, or histidine) as stimuli-responsive units. Cleavage of the cross-linking DNAzyme substrates by the respective cofactors yields hydrogel coatings with a reduced stiffness and higher porosity that allow the release of the loads. A further approach involved the application of the HCR process to assemble the bilayer hydrogel microcapsules that are unlocked by two cooperative triggers. Bilayer microcapsules consisting of a K+ ions-stabilized G-quadruplex/18-crown-6-ether (CE) responsive layer and a Mg2+ ion DNAzyme-responsive layers are presented. Unlocking and locking of the G-quadruplex cross-linked layer by 18-crown-6-ether and K+ ions, respectively, in the presence of Mg2+ ions allow the switchable controlled release of the load. In addition, the intercommunication of two kinds of stimuli-responsive bilayer hydrogel microcapsules carrying two different loads (tetramethylrhodamine-dextran, TMR-D, and CdSe/ZnS quantum dots) is demonstrated. The intercommunication process involves the stimuli-triggered generation of "information transfer" strands from one microcapsule to another that activate the release of the loads.

Keywords

DNA nanotechnology; DNAzyme; G-quadruplex; hybridization chain reaction; nanomedicine.

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