Kim Minjeong, Choi Myoung Gil, Ra Ho Won, Park Seung Bin, Kim Yong-Joo, Lee Kyubock
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 34134, Korea.
Materials (Basel). 2018 Feb 13;11(2):296. doi: 10.3390/ma11020296.
The encapsulation of living cells is appealing for its various applications to cell-based sensors, bioreactors, biocatalysts, and bioenergy. In this work, we introduce the encapsulation of multiple microalgal cells in hollow polymer shells of rhombohedral shape by the following sequential processes: embedding of microalgae in CaCO₃ crystals; layer-by-layer (LbL) coating of polyelectrolytes; and removal of sacrificial crystals. The microcapsule size was controlled by the alteration of CaCO₃ crystal size, which is dependent on CaCl₂/Na₂CO₃ concentration. The microalgal cells could be embedded in CaCO₃ crystals by a two-step process: heterogeneous nucleation of crystal on the cell surface followed by cell embedment by the subsequent growth of crystal. The surfaces of the microalgal cells were highly favorable for the crystal growth of calcite; thus, micrometer-sized microalgae could be perfectly occluded in the calcite crystal without changing its rhombohedral shape. The surfaces of the microcapsules, moreover, could be decorated with gold nanoparticles, Fe₃O₄ magnetic nanoparticles, and carbon nanotubes (CNTs), by which we would expect the functionalities of a light-triggered release, magnetic separation, and enhanced mechanical and electrical strength, respectively. This approach, entailing the encapsulation of microalgae in semi-permeable and hollow polymer microcapsules, has the potential for application to microbial-cell immobilization for high-biomass-concentration cultivation as well as various other bioapplications.
活细胞的封装因其在基于细胞的传感器、生物反应器、生物催化剂和生物能源等各种应用中具有吸引力。在这项工作中，我们通过以下连续过程将多个微藻细胞封装在菱面体形状的中空聚合物壳中：将微藻嵌入碳酸钙晶体中；聚电解质的逐层（LbL）涂层；以及去除牺牲晶体。微胶囊的尺寸通过改变碳酸钙晶体的尺寸来控制，而碳酸钙晶体尺寸取决于氯化钙/碳酸钠的浓度。微藻细胞可以通过两步过程嵌入碳酸钙晶体中：晶体在细胞表面的异质成核，随后通过晶体的后续生长将细胞嵌入。微藻细胞的表面非常有利于方解石晶体的生长；因此，微米级的微藻可以完美地封闭在方解石晶体中而不改变其菱面体形状。此外，微胶囊的表面可以用金纳米颗粒、四氧化三铁磁性纳米颗粒和碳纳米管（CNT）进行修饰，我们预期分别通过这些修饰实现光触发释放、磁分离以及增强机械和电气强度的功能。这种将微藻封装在半透性中空聚合物微胶囊中的方法，具有应用于高生物量浓度培养的微生物细胞固定化以及各种其他生物应用的潜力。
