Diafiltration is a membrane filtration technique that rapidly removes permeable molecules from a solution by controlling the tangential and orthogonal flows over a membrane and by replenishing the permeate with an equivalent amount of replacement buffer. However, its application to the purification of many key biomaterials and nanomaterials has been limited by the large dead volume (>10 mL) that is required to automate the process. To address this challenge, we have developed a diafiltration-on-a-chip device that can process low-volume samples (50 μL). The key innovation of this device is a magnetically-driven on-chip peristaltic pump that is able to continuously drive fluid flow at rates as high as 50 mL h⁻¹ with minimal external instrumentation and a dead volume of <50 μL. To demonstrate the utility of this device, we purified microbeads from dye with >99% purity and >96% retention within two hours. We additionally showed that cells could be purified from microbeads with >97% purity and >97% retention in two hours. Because our approach requires minimal instrumentation, it is well suited for on-chip parallelization, which was demonstrated by incorporating four complete diafiltration systems onto a single credit card-sized chip.

中文翻译：

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使用集成的磁性蠕动微泵进行微流控芯片渗滤

渗滤是一种膜过滤技术，可通过控制膜上的切向和正交流并通过向渗透液中加入等量的置换缓冲液来快速从溶液中去除渗透性分子。但是，其在许多关键生物材料和纳米材料的纯化中的应用受到自动化过程所需的大量死体积（> 10 mL）的限制。为了应对这一挑战，我们开发了一种芯片上渗滤设备，该设备可以处理小体积样品（50μL）。该设备的关键创新是电磁驱动的片上蠕动泵，该泵能够以高达50 mL h ^-1的速度连续驱动流体流动外部仪器最少，死体积<50μL。为了证明该设备的实用性，我们在两个小时内从染料中纯化了微珠，纯度> 99％，保留率> 96％。我们还表明，可以在两小时内从微珠中纯化出细胞，其纯度> 97％，保留率> 97％。由于我们的方法所需的仪器最少，因此非常适合片上并行化，这是通过在单个信用卡大小的芯片上集成四个完整的渗滤系统来证明的。