Optimisation of bacterial release from a stable microfluidic-generated water-in-oil-in-water emulsion.
Optimisation of bacterial release from a stable microfluidic-generated water-in-oil-in-water emulsion.
复制标题
DOI：
10.1039/d0ra10954a
复制
发表时间：
2021-02-10
期刊：
影响因子：
3.9
通讯作者：
Gkatzionis K
中科院分区：
文献类型：
--
作者：
Mohd Isa NS;El Kadri H;Vigolo D;Gkatzionis K
液滴微流控技术应用于水包油包水（W/O/W）乳化液中细菌的包封，可以产生尺寸可控的单分散液滴。本实验研究了水乳/水乳/水乳状液中细菌的释放，双乳结构对细菌生长和代谢活性的影响，以及细菌释放的稳定性和机制。采用双聚焦结微流控装置在可控压力下形成W/O/W乳液，形成直径约为100 μm的微滴，内水相（W1）直径约为40-50 μm。将gfp标记的大肠杆菌（大肠杆菌- gfp）包裹在W1液滴内，通过监测液滴大小和成乳行为来研究乳剂的稳定性。采用亲水性（Tween 80）和亲脂性表面活性剂（聚甘油聚蓖麻油酸酯）稳定双乳，并通过改变渗透平衡，在W1相（低渗透）或W2相（高渗透）中加入NaCl来破坏双乳的稳定。采用琼脂镀法监测大肠杆菌-绿色荧光蛋白的释放，测定释放细菌的菌落形成单位（CFU），并采用荧光显微镜观察滴滴释放机制。NaCl浓度越高，Tween 80用量越少，大肠杆菌gfp的释放量越高。显微镜观察发现，细菌的释放机制分为两步：双W/O/W乳剂液滴分裂释放W1液滴，形成二次双乳，然后W1液滴坍塌释放大肠杆菌- gfp进入连续水相。包封提高了活力和代谢活性。营养物质可以穿过油层。在高渗透压和低表面活性剂浓度下，细菌释放量增加，乳液稳定性降低。观察到两步释放机制。
Application of droplet microfluidics for the encapsulation of bacteria in water-in-oil-in-water (W/O/W) emulsion allows for production of monodisperse droplets with controllable size. In this study the release of bacteria from W/O/W emulsion, the effect of the double emulsion structure on bacterial growth and metabolic activity, and the stability and mechanism of bacterial release were investigated. W/O/W emulsions were formed using a double flow-focusing junction microfluidic device under controlled pressure to produce droplets of approximately 100 μm in diameter containing an inner aqueous phase (W1) of about 40–50 μm in diameter. GFP-labelled Escherichia coli (E. coli-GFP) bacteria were encapsulated within the W1 droplets and the stability of emulsions was studied by monitoring droplet size and creaming behaviour. The double emulsions were stabilised using a hydrophilic (Tween 80) and a lipophilic surfactant (polyglycerol polyricinoleate) and were destabilised by altering the osmotic balance, adding NaCl either in the inner W1 phase (hypo-osmotic) or outer W2 phase (hyper-osmotic). The release of E. coli-GFP was monitored by plating on agar whereby the colony form unit (CFU) of the released bacteria was determined while fluorescent microscopy was employed to observe the mechanism of release from the droplets. The release of E. coli-GFP was significantly increased with higher concentrations of NaCl and lower amounts of Tween 80. Microscopic observation revealed a two-step mechanism for the release of bacteria: double W/O/W emulsion droplet splitting to release W1 droplets forming a secondary double emulsion followed by the collapse of W1 droplets to release E. coli-GFP into the continuous aqueous phase. Encapsulation enhanced viability and metabolic activity. Nutrients can cross the oil layer. Bacterial release increased while emulsion stability decreased at high osmotic pressure and low surfactant concentration. Two-step release mechanism observed.
登录
查看更多内容
影响因子：
4.4
作者：
Hong, Yongsuk;Brown, Derick G.
通讯作者：
Brown, Derick G.
影响因子：
3.9
作者：
EL Kadri, Hani;Gun, Ramazan;Gkatzionis, Konstantinos
通讯作者：
Gkatzionis, Konstantinos
影响因子：
3.9
作者：
González-Ochoa, H;Ibarra-Bracamontes, L;Arauz-Lara, JL
通讯作者：
Arauz-Lara, JL
影响因子：
4.9
作者：
Ngai, T;Behrens, SH;Auweter, H
通讯作者：
Auweter, H
影响因子：
8.1
作者：
El Kadri, Hani;Lalou, Sofia;Gkatzionis, Konstantinos
通讯作者：
Gkatzionis, Konstantinos