Directed migration of particles and molecules in a temperature gradient field, which is known as thermophoresis or the Soret effect, is of fundamental importance for mass transfer in colloid science and life sciences. However, thermophoretic tweezers that enable versatile particle manipulation have remained elusive due to the complex underlying physical forces in thermophoresis and the lack of general thermophilic particles above room temperature. Herein, we exploit entropic response and permittivity gradient at the particle–solvent interface to optically generated thermal gradient to achieve the thermophoretic trapping and dynamic manipulation of charged particles over an optothermal-responsive substrate. Engineering the interfacial properties, i.e., the surface charge of particles and the ionic strength of the solvent, further enhances the trapping efficiency. Through the rational design of optothermal potential profiles and substrate geometries, we have achieved various tweezing functionalities, including particle assembly, alignment, rotation and guiding, as well as precise transport of single nanoparticles. Based on the general concept of entropic change of polarized molecules structured at the particle–solvent interlayer, the thermophoretic tweezers are applicable to various types of particles, biological cells, and molecules and a wide range of solvents.

中文翻译：

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界面熵驱动的热泳镊子

粒子和分子在温度梯度场中的定向迁移（称为热泳或Soret效应）对于胶体科学和生命科学中的质量转移至关重要。然而，由于热泳中潜在的复杂物理力以及在室温以上缺乏一般的嗜热粒子，使得能够进行多种粒子操纵的热泳镊子仍然难以捉摸。在本文中，我们利用粒子-溶剂界面处的熵响应和介电常数梯度来光学生成热梯度，以实现在光热响应基板上的带电粒子的热泳捕获和动态操纵。工程界面属性，即，颗粒的表面电荷和溶剂的离子强度，进一步提高了捕集效率。通过合理设计光热势分布和基板几何形状，我们实现了各种钳夹功能，包括颗粒组装，对准，旋转和引导以及单个纳米颗粒的精确运输。基于在粒子-溶剂中间层构造的极化分子的熵变的一般概念，热泳镊子适用于各种类型的粒子，生物细胞，分子和各种溶剂。