Reversible Trapping of Colloids in Microgrooved Channels via Diffusiophoresis under Steady-State Solute Gradients.
Reversible Trapping of Colloids in Microgrooved Channels via Diffusiophoresis under Steady-State Solute Gradients.
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DOI：
10.1103/physrevlett.125.248002
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发表时间：
2020-07
影响因子：
8.6
通讯作者：
Naval Singh;G. Vladisavljević;F. Nadal;C. Cottin-Bizonne;C. Pirat;G. Bolognesi
中科院分区：
文献类型：
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作者：
Naval Singh;G. Vladisavljević;F. Nadal;C. Cottin-Bizonne;C. Pirat;G. Bolognesi
胶体在死端结构中的受控传输是一种关键能力，可以实现广泛的应用，例如生化分析，药物输送和地下石油开采。这封信提出了一种新的陷阱机制，允许快速（即，在几分钟内）和通过具有不同盐度水平的平行流在死端微槽内的亚微米颗粒的可逆累积。对于第一次，在死端结构的粒子聚焦下实现稳态梯度。共焦显微镜分析和数值研究表明，颗粒被困在一个流动的回流区域内的凹槽，由于扩散电泳运输和流体动力学效应的组合。与直觉相反，在聚焦点处的粒子速度并不为零，因此，粒子被连续地输送进出聚焦点。累积过程也是可逆的，并且可以通过经由流动切换阀控制流的盐浓度来循环地捕获和释放胶体。
The controlled transport of colloids in dead-end structures is a key capability that can enable a wide range of applications, such as biochemical analysis, drug delivery, and underground oil recovery. This Letter presents a new trapping mechanism that allows the fast (i.e., within a few minutes) and reversible accumulation of submicron particles within dead-end microgrooves by means of parallel streams with different salinity level. For the first time, particle focusing in dead-end structures is achieved under steady-state gradients. Confocal microscopy analysis and numerical investigations show that the particles are trapped at a flow recirculation region within the grooves due to a combination of diffusiophoresis transport and hydrodynamic effects. Counterintuitively, the particle velocity at the focusing point is not vanishing and, hence, the particles are continuously transported in and out of the focusing point. The accumulation process is also reversible and one can cyclically trap and release the colloids by controlling the salt concentration of the streams via a flow switching valve.