Mechanics of semiflexible chains formed by poly(ethylene glycol)-linked paramagnetic particles
Mechanics of semiflexible chains formed by poly(ethylene glycol)-linked paramagnetic particles
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DOI：
10.1103/physreve.68.021402
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发表时间：
2003-08-01
影响因子：
2.4
通讯作者：
Gast, AP
中科院分区：
文献类型：
--
作者：
Biswal, SL;Gast, AP
磁流变颗粒，永久连接成链，提供了一种磁驱动手段来操纵微观流体流动。顺磁胶体粒子在外磁场作用下获得偶极矩形成可逆链。通过化学连接顺磁性胶体颗粒，可以创建柔性磁响应链。我们使用链亲和素-生物素结合连接顺磁微球。将链霉亲和素包覆的微球放置在流动池中，并施加磁场，使颗粒形成链。然后在有电场存在的情况下加入双生物素-聚乙二醇分子的聚合连接剂溶液。这些连接的链对磁场保持响应；然而，在没有外部磁场的情况下，这些链由于热运动而弯曲和弯曲。链的柔韧性由颗粒之间的间隔分子的长度决定，并通过弯曲刚度或弯曲刚度来量化。为了了解链的机械性能，我们使用各种光学捕获实验来测量链的弯曲刚度。增加连接剂中聚乙二醇链的长度可以增加链的柔韧性。
Magnetorheological particles, permanently linked into chains, provide a magnetically actuated means to manipulate microscopic fluid flow. Paramagnetic colloidal particles form reversible chains by acquiring dipole moments in the presence of an external magnetic field. By chemically connecting paramagnetic colloidal particles, flexible magnetoresponsive chains can be created. We link the paramagnetic microspheres using streptavidin-biotin binding. Streptavidin coated microspheres are placed in a flow cell and a magnetic field is applied, causing the particles to form chains. Then a solution of polymeric linkers of bis-biotin-poly(ethylene glycol) molecules is added in the presence of the field. These linked chains remain responsive to a magnetic field; however, in the absence of an external magnetic field these chains bend and flex due to thermal motion. The chain flexibility is determined by the length of the spacer molecule between particles and is quantified by the flexural rigidity or bending stiffness. To understand the mechanical properties of the chains, we use a variety of optical trapping experiments to measure the flexural rigidity. Increasing the length of the poly(ethylene glycol) chain in the linker increases the flexibility of the chains.