Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
ACS Appl Mater Interfaces. 2020 Jul 15;12(28):31124-31136. doi: 10.1021/acsami.0c06711. Epub 2020 Jul 2.
A method to assemble loaded stimuli-responsive DNA-polyacrylamide hydrogel-stabilized microcapsules is presented. The method involves coating substrate-loaded CaCO 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 CaCO 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 = Mg ions, Zn 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 Mg 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 Mg 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.
一种组装负载刺激响应 DNA-聚丙烯酰胺水凝胶稳定微胶囊的方法被提出。该方法涉及包被带有核酸启动子单元的基底负载 CaCO3 微球，并在微胶囊上交联 DNA 修饰的聚丙烯酰胺链，使用杂交链式反应（HCR）产生 DNA 交联水凝胶涂层。CaCO3 颗粒的溶解产生了负载基底的水凝胶保护微胶囊。微胶囊-水凝胶壳包括工程化的刺激响应寡核苷酸交联剂，控制水凝胶壳的刚性，允许负载的触发释放。一种方法包括将辅因子依赖性 DNA 酶单元掺入交联水凝胶层中（辅因子=Mg 离子、Zn 离子或组氨酸）作为刺激响应单元。相应的辅因子切割交联 DNA 酶底物会产生刚性降低、孔隙率增加的水凝胶涂层，从而允许负载释放。另一种方法涉及应用 HCR 过程来组装双层水凝胶微胶囊，这些微胶囊通过两个协同触发解锁。展示了由 K 离子稳定的 G-四链体/18-冠醚（CE）响应层和 Mg 离子 DNA 酶响应层组成的双层微胶囊。在存在 Mg 离子的情况下，通过 18-冠醚和 K 离子分别解锁和锁定 G-四链体交联层，允许负载的可切换控制释放。此外，还演示了两种具有两种不同负载（四甲基罗丹明葡聚糖，TMR-D 和 CdSe/ZnS 量子点）的刺激响应双层水凝胶微胶囊的互通讯。互通讯过程涉及从一个微胶囊到另一个微胶囊的刺激触发产生“信息传递”链，从而激活负载的释放。
