Auto-production of biosurfactants reverses the coffee ring effect in a bacterial system.
Auto-production of biosurfactants reverses the coffee ring effect in a bacterial system.
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DOI：
10.1038/ncomms2746
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发表时间：
2013
影响因子：
16.6
通讯作者：
中科院分区：
文献类型：
--
作者：
被称为“咖啡环效应”的物质在蒸发液滴边缘的沉积是由径向向外的毛细管流引起的。这一现象在包括胶体和细菌系统在内的各种系统中都很常见。表面活性剂在抵消这些咖啡环沉积方面的作用与被称为Marangoni涡的局部涡旋的发生有关。在这里，我们表明这些旋流是普遍的，不仅导致胶体的均匀沉积，而且也发生在活的细菌系统中。对铜绿假单胞菌的实验表明，生物表面活性剂的自动生产在细菌干燥时创造均匀的沉积方面起着至关重要的作用。此外，在生物相关的条件下，除了涡旋区域外，还观察到复杂的随时间变化的流动，这在更低的表面活性剂浓度下也能有效地逆转咖啡环效应。咖啡环效应在含有悬浮物的液滴干燥过程中经常观察到，导致液滴边缘沉积。Sempels等人。表明在活的细菌系统中自行产生的生物表面活性剂逆转了咖啡环效应，并导致均匀的沉积。
The deposition of material at the edge of evaporating droplets, known as the ‘coffee ring effect’, is caused by a radially outward capillary flow. This phenomenon is common to a wide array of systems including colloidal and bacterial systems. The role of surfactants in counteracting these coffee ring depositions is related to the occurrence of local vortices known as Marangoni eddies. Here we show that these swirling flows are universal, and not only lead to a uniform deposition of colloids but also occur in living bacterial systems. Experiments on Pseudomonas aeruginosa suggest that the auto-production of biosurfactants has an essential role in creating a homogeneous deposition of the bacteria upon drying. Moreover, at biologically relevant conditions, intricate time-dependent flows are observed in addition to the vortex regime, which are also effective in reversing the coffee ring effect at even lower surfactant concentrations. The coffee ring effect is commonly observed in drying droplets containing suspended matter leading to a deposition at the droplet edge. Sempels et al. show that self-generated biosurfactants in living bacterial systems reverse the coffee ring effect and result in a homogeneous deposition.
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影响因子：
3.9
作者：
Hu, H;Larson, RG
通讯作者：
Larson, RG
影响因子：
--
作者：
ANIANSSON, EA;WALL, SN
通讯作者：
WALL, SN
影响因子：
9.9
作者：
Sefiane, K
通讯作者：
Sefiane, K
DOI：
10.1016/0927-7757(96)03561-3
发表时间：
1996-08-20
影响因子：
5.2
作者：
Fruhner, H;Wantke, KD
通讯作者：
Wantke, KD
影响因子：
4.6
作者：
Dunn, G. J.;Wilson, S. K.;Sefiane, K.
通讯作者：
Sefiane, K.