College of Marine Life Science, Ocean University of China, Qingdao, 266003, PR China.
College of Marine Life Science, Ocean University of China, Qingdao, 266003, PR China.
Int J Biol Macromol. 2017 Dec;105(Pt 1):924-930. doi: 10.1016/j.ijbiomac.2017.07.124. Epub 2017 Jul 20.
Multilayer alginate hydrogel beads (MAHBs), which were prepared by emulsion method, had been fabricated via the ionic crosslinking between calcium ion (Ca) and carboxylic group of alginate and utilized as encapsulating material for oral delivery of a model probiotic bacteria Bifidobacterium breve. Optical and fluorescence microscopy obviously showed the microorganism cells were encapsulated in the core beads. The viability of B. breve cells encapsulated in MAHBs was significantly enhanced compared with ordinary free cultured ones, the top CFU per mL were (3.70±0.20)×10 and (2.61±0.22)×10 respectively. Meanwhile, B. breve cells encapsulated in MAHBs could still keep viability even after 12h' culture in the broth with pH value similar to gastric juice, while the free cultured cells had no activity in such culture condition. To test applicability of MAHBs for the delivery of microorganisms, a Gram-positive strain, Staphylococcus aureus, as well as a Gram-negative strain, Escherichia coli, were also employed and encapsulated in MAHBs. Similar to B. breve cells, the viability of encapsulated S. aureus cells and E. coli cells in extreme pH value environment were significantly promoted. In addition, a high α-amylase yielding efficiency Bacillus subtilis strain was found and encapsulated in MAHBs. Compared with control groups, MAHBs encapsulated B. subtilis cells produced more α-amylase after 240h' culture, while the release of this enzyme was sustained rather than the burst release like free cultured group, which means this system would not reduce metabolite yield while having long term sustained-release effect. In summary, MAHBs are favorable biological carrier, which has the potential of being applied to oral delivery of probiotics.
多层海藻酸钠水凝胶珠（MAHBs）通过乳化法制备，通过钙离子（Ca）与海藻酸钠的羧基之间的离子交联制备，并用作包封短双歧杆菌的模型益生菌的口服递送的包封材料。光学和荧光显微镜明显显示微生物细胞被包封在核心珠中。与普通自由培养的细胞相比，包封在 MAHBs 中的 B. breve 细胞的存活率显著提高，每毫升的最高 CFU 分别为（3.70±0.20）×10 和（2.61±0.22）×10。同时，即使在与胃液相似的 pH 值的肉汤中培养 12 小时后，包封在 MAHBs 中的 B. breve 细胞仍能保持活力，而自由培养的细胞在这种培养条件下没有活性。为了测试 MAHBs 用于微生物传递的适用性，还将革兰氏阳性菌金黄色葡萄球菌和革兰氏阴性菌大肠杆菌包封在 MAHBs 中。与 B. breve 细胞类似，在极端 pH 值环境中包封的金黄色葡萄球菌细胞和大肠杆菌细胞的存活率也得到了显著提高。此外，发现并包封在 MAHBs 中的枯草芽孢杆菌菌株具有高α-淀粉酶产率。与对照组相比，MAHBs 包封的枯草芽孢杆菌细胞在 240 小时培养后产生了更多的α-淀粉酶，而酶的释放是持续的而不是像自由培养组那样的爆发释放，这意味着该系统在具有长期持续释放作用的同时不会降低代谢产物的产量。总之，MAHBs 是一种有利的生物载体，具有在益生菌口服递送上应用的潜力。
