Manipulation of coacervate droplets with an electric field.
Manipulation of coacervate droplets with an electric field.
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DOI：
10.1073/pnas.2203483119
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发表时间：
2022-08-09
影响因子：
11.1
通讯作者：
中科院分区：
文献类型：
--
作者：
生物材料的许多独特特性源于其组成分子的高电荷性质及其漫射的反离子云，这通常使这些材料具有本质极化，从而对电场具有高度响应。我们研究了一种这种合成材料，这种材料通过形成聚电解质凝聚体转移到蒸馏水中，以提取多余的反离子，形成高度稳定的液滴悬浮液，其中单个液滴及其大结构可以精确地操纵，其场强相当于9伏电池的大小。这些材料在封装、运输和递送各种各样的货物方面很有用，在制造和医药的许多应用中，作为理解生命系统电动力学方面的模型系统。许多生物聚合物是高度带电的，并且在许多聚合物混合物的情况下，它们倾向于相分离，这是链连通性和相关的相对较低的聚合物混合熵的自然结果。最近，人们已经认识到，由这种聚电解质混合物形成的相分离结构，称为“复杂凝聚体”，是生命系统必不可少的许多生物结构和过程的基础，并且人们对理解这种类型的相分离过程的独特物理特征产生了浓厚的兴趣。在本工作中，我们特别关注聚电解质混合溶液相分离后形成的稳定凝聚液滴的场响应性，然后暴露于去离子水中，使液滴界面层获得粘弹性特性，从而强烈地稳定其不结聚。我们表明，我们可以用相对较低的电压电场（约10 V/cm）精确控制单个液滴及其阵列的位置，并且振荡场的施加会导致链的形成，并将这些链粗化为长纤维。这种类似相分离的过程通常在受到更大场强的固体胶体颗粒的电流变流体中观察到。这些凝聚体的电流变特性的关键是当液滴被引入去离子水时界面粘弹性的改变以及液滴的高极化性，类似于许多活细胞的特性。由于许多不同的分子有效载荷可以结合到这些稳定的液滴中，我们预计会有许多应用。
Many of the unique properties of biological materials are derived from the highly charged nature of the constituent molecules and their diffuse counterion clouds, which often render such materials intrinsically polarizable, and thus highly responsive to electric fields. We investigate a synthetic material of this kind created through the formation of polyelectrolyte coacervates transferred to distilled water to extract excess counterions to form highly stable droplet suspensions in which individual droplets, and their large configurations, can be precisely manipulated with field strengths comparable in magnitude to a 9-volt battery. These materials should be useful in encapsulating, transporting, and delivering various cargos in numerous applications in manufacturing and medicine and as a model system for understanding electrodynamic aspects of living systems. Many biopolymers are highly charged, and as in the case of many polymer mixtures, they tend to phase separate as a natural consequence of chain connectivity and an associated relatively low entropy of polymer mixing. Recently, it has become appreciated that the phase-separated structures formed by such polyelectrolyte blends, called “complex coacervates,” underlie numerous biological structures and processes essential to living systems, and there has been intense interest in understanding the unique physical features of this type of phase-separation process. In the present work, we are particularly concerned with the field responsiveness of stabilized coacervate droplets formed after the phase separation of polyelectrolyte blend solution and then exposed to deionized water, making the droplet interfacial layer acquire a viscoelastic character that strongly stabilizes it against coalescence. We show that we can precisely control the positions of individual droplets and arrays of them with relatively low-voltage electric fields (on the order of 10 V/cm) and that the imposition of an oscillatory field gives rise to chain formation with coarsening of these chains into long fibers. Such a phase-separation–like process is generally observed in electrorheological fluids of solid colloidal particles subjected to much larger field strengths. The key to these coacervates’ electrorheological properties is the altered interfacial viscoelastic properties when the droplets are introduced into deionized water and the associated high polarizability of the droplets, similar to the properties of many living cells. Since many different molecular payloads can be incorporated into these stable droplets, we anticipate many applications.
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影响因子：
5.5
作者：
Lösche, M;Schmitt, J;Kjaer, K
通讯作者：
Kjaer, K
影响因子：
3.4
作者：
Desmond, Kenneth W.;Young, Pearl J.;Weeks, Eric R.
通讯作者：
Weeks, Eric R.
影响因子：
3
作者：
HALSEY, TC;MARTIN, JE
通讯作者：
MARTIN, JE
影响因子：
16.6
作者：
Drobot B;Iglesias-Artola JM;Le Vay K;Mayr V;Kar M;Kreysing M;Mutschler H;Tang TD
通讯作者：
Tang TD
影响因子：
1.6
作者：
Hameroff, S;Nip, A;Tuszynski, J
通讯作者：
Tuszynski, J