Tuning of salt separation efficiency by flow rate control in microfluidic dynamic dialysis
Tuning of salt separation efficiency by flow rate control in microfluidic dynamic dialysis
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DOI：
10.1007/s10404-019-2277-z
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发表时间：
2019-10-01
影响因子：
2.8
通讯作者：
de Planque, Maurits R. R.
中科院分区：
文献类型：
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作者：
Kalikavunkal, Prameen C.;Green, Nicolas G.;de Planque, Maurits R. R.
微升规模的分离过程对于生物医学研究和小容量临床样本的临床点诊断非常重要。质谱仪和场效应感测法等分析方法需要样品脱盐，但盐浓度太低会破坏蛋白质结构和生物分子间的相互作用。在这项工作中，我们研究了从蛋白质溶液中提取盐分是否可以通过动态透析参数进行控制。采用激光切割法制备了具有5 kDa截留分子量纤维素膜的微流控逆流透析器，可在较宽的进料流量和透析流量下工作。结果表明，在合适的流动条件下，最显著的是进料流量，保留盐浓度可以达到输入氯化钠浓度的0.1%~99%。实验数据与基于扩散的传质理论模型吻合较好。在白蛋白浓度为50 mg/mL的条件下，盐透析性能相似，接近血浆蛋白含量，通宵连续透析不会恶化，表明膜污染最小。该透析器构造方法与所有平面膜兼容，能够实现可调动态透析，用于广泛的在线微流控生物分子分离。
Microliter-scale separation processes are important for biomedical research and point-of-care diagnostics with small-volume clinical samples. Analytical assays such as mass spectrometry and field effect sensing necessitate sample desalting, but too low a salt concentration can disrupt protein structures and biomolecular interactions. In this work, we investigated whether salt extraction from a protein solution can be controlled by dynamic dialysis parameters. A microfluidic counter-flow dialyzer with a 5 kDa molecular weight cut-off cellulose membrane was fabricated by laser cutting and operated with a wide range of feed and dialysis flow rates. It was found that with the appropriate flow conditions, most notably the feed flow rate, retentate salt concentrations from 0.1 to 99% of the input NaCl concentration can be achieved. The experimental data were in good agreement with a theoretical diffusion-based mass transfer model. The salt dialysis performance was similar in the presence of 50 mg/mL albumin, approximating blood plasma protein content, and did not deteriorate with overnight continuous dialysis, indicating minimal membrane fouling. The dialyzer construction method is compatible with all planar membranes, enabling implementation of tuneable dynamic dialysis for a wide range of on-line microfluidic biomolecular separations.