Modulating the release of Escherichia coli in double W1/O/W2 emulsion globules under hypo-osmotic pressure
Modulating the release of Escherichia coli in double W1/O/W2 emulsion globules under hypo-osmotic pressure
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DOI：
10.1039/c6ra17091a
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发表时间：
2016-01-01
期刊：
影响因子：
3.9
通讯作者：
Gkatzionis, Konstantinos
中科院分区：
文献类型：
--
作者：
EL Kadri, Hani;Gun, Ramazan;Gkatzionis, Konstantinos
双重水包油包水（W-1/O/W-2）乳液具有包封细菌的潜力，并且如果其结构不稳定，则可以以时间控制的方式促进细菌释放。W-1/O/W-2乳剂中细菌释放机制的描述仅限于高渗条件;然而，低渗条件下细菌释放的机制不同，细菌的存在可能影响乳剂，反之亦然。在这项工作中，研究了在存在或不存在GFP标记的大肠杆菌（E. coli）的情况下W-1/O/W-2乳液的稳定性和释放特性。coli-GFP）。还测定了通过在低渗溶液中稀释乳剂来改变渗透平衡的影响。W-1/O/W-2乳液的制备及E.使用两步均质化方法实现coli-GFP包封，并通过改变亲水性表面活性剂（Tween 80，0.5-10%）、亲脂性表面活性剂（PGPR，1-8%）和W-1（20%和40%）的浓度来改变结构。E. coli-GFP通过培养监测并使用荧光显微镜观察。E.在高浓度W-1和低浓度Tween 80或PGPR时，当渗透压平衡改变时，coli-GFP表达显著增加（P < 0.05）。细菌释放是由于油球破裂而发生的，细菌的活力不受释放机制的影响。细菌浓度在乳化的第一阶段对复乳结构有影响，而在渗透平衡改变阶段对复乳结构无影响。
Double water-in-oil-in-water (W-1/O/W-2) emulsions have the potential to encapsulate bacteria and their structure if destabilised can facilitate bacterial release in a time controlled manner. The description of release mechanisms of bacteria in W-1/O/W-2 emulsions is limited to hyper-osmotic conditions; however, the mechanism responsible for bacterial release in hypo-osmotic conditions is different and the presence of bacteria may affect the emulsion and vice versa. In this work, the stability and release properties of W-1/O/W-2 emulsions were studied with or without the presence of GFP-tagged Escherichia coli (E. coli-GFP) in the inner aqueous phase (W-1). The impact of altering the osmotic balance by diluting the emulsion in a hypo-osmotic solution was also determined. W-1/O/W-2 emulsion preparation and E. coli-GFP encapsulation was achieved using a two-step homogenisation process and structure was changed by altering the concentration of hydrophilic surfactant (Tween80, 0.5-10%), lipophilic surfactant (PGPR, 1-8%) and W-1 (20% and 40%). The release of E. coli-GFP was monitored by culture and observed using fluorescence microscopy. The release of E. coli-GFP was significantly (P < 0.05) increased when the osmotic balance was altered and at high amounts of W-1 and low concentrations of Tween80 or PGPR. Bacterial release occurred due to oil globule bursting and the viability of bacteria was unaffected by the release mechanism. The concentration of bacteria affected the double emulsion structure during the first step of emulsification but had no effect on emulsion structure during osmotic balance alteration.