Key Laboratory for Green Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University , Tianjin 300072, China.
ACS Appl Mater Interfaces. 2013 Oct 23;5(20):9991-7. doi: 10.1021/am403523d. Epub 2013 Oct 4.
Microcapsules with diverse wall structures may exhibit different performance in specific applications. In the present study, three kinds of mussel-inspired polydopamine (PDA) microcapsules with different wall structures have been prepared by a template-mediated method. More specifically, three types of CaCO3 microspheres (poly(allylamine hydrochloride), (PAH)-doped CaCO3; pure-CaCO3; and poly(styrene sulfonate sodium), (PSS)-doped CaCO3) were synthesized as sacrificial templates, which were then treated by dopamine to obtain the corresponding PDA-CaCO3 microspheres. Through treating these microspheres with disodium ethylene diamine tetraacetic acid (EDTA-2Na) to remove CaCO3, three types of PDA microcapsules were acquired: that was (1) PAH-PDA microcapsule with a thick (∼600 nm) and highly porous capsule wall composed of interconnected networks, (2) pure-PDA microcapsule with a thick (∼600 nm) and less porous capsule wall, (3) PSS-PDA microcapsule with a thin (∼70 nm) and dense capsule wall. Several characterizations confirmed that a higher degree in porosity and interconnectivity of the capsule wall would lead to a higher mass transfer coefficient. When serving as the carrier for catalase (CAT) immobilization, these enzyme-encapsulated PDA microcapsules showed distinct structure-related activity and stability. In particular, PAH-PDA microcapsules with a wall of highly interconnected networks displayed several significant advantages, including increases in enzyme encapsulation efficiency and enzyme activity/stability and a decrease in enzyme leaching in comparison with other two types of PDA microcapsules. Besides, this hierarchically structured PAH-PDA microcapsule may find other promising applications in biocatalysis, biosensors, drug delivery, etc.
具有不同壁结构的微胶囊在特定应用中可能表现出不同的性能。在本研究中，通过模板介导的方法制备了三种具有不同壁结构的贻贝类聚多巴胺（PDA）微胶囊。更具体地说，合成了三种类型的 CaCO3 微球（聚（盐酸烯丙胺），（PAH）掺杂的 CaCO3；纯-CaCO3；和聚（苯乙烯磺酸钠），（PSS）掺杂的 CaCO3）作为牺牲模板，然后用多巴胺处理得到相应的 PDA-CaCO3 微球。通过用乙二胺四乙酸二钠（EDTA-2Na）处理这些微球去除 CaCO3，得到了三种类型的 PDA 微胶囊：（1）PAH-PDA 微胶囊，其具有由相互连接的网络组成的厚（约 600nm）且高度多孔的胶囊壁，（2）纯-PDA 微胶囊，其具有厚（约 600nm）且较少多孔的胶囊壁，（3）PSS-PDA 微胶囊，其具有薄（约 70nm）且致密的胶囊壁。几种特性证实，胶囊壁的孔隙度和互连度越高，传质系数就越高。当用作固定化过氧化氢酶（CAT）的载体时，这些包封酶的 PDA 微胶囊表现出明显的结构相关活性和稳定性。特别是，具有高度互连网络壁的 PAH-PDA 微胶囊在几个方面具有显著的优势，包括增加了酶包封效率和酶活性/稳定性，以及与其他两种 PDA 微胶囊相比，酶浸出率降低。此外，这种具有层次结构的 PAH-PDA 微胶囊可能在生物催化、生物传感器、药物输送等方面有其他有前途的应用。
