Nondiffusive mechanisms enhance protein uptake rates in ion exchange particles
Nondiffusive mechanisms enhance protein uptake rates in ion exchange particles
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DOI：
10.1073/pnas.0237084100
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发表时间：
2003-01-21
影响因子：
11.1
通讯作者：
Lenhoff, AM
中科院分区：
文献类型：
--
作者：
Dziennik, SR;Belcher, EB;Lenhoff, AM
扫描共聚焦荧光显微镜和多光子荧光显微镜被用来成像的蛋白质溶菌酶的摄取到个人的离子交换色谱颗粒在填充床在真实的时间。在所有研究的吸附剂中，在低盐浓度下观察到渗透到颗粒中的自锐浓度前沿，但仅在某些材料中持续到100 mM离子强度。在其他吸附剂中，在这些较高的盐浓度下观察到扩散分布，过渡区在中间盐浓度下在前部显示出明显的荧光峰。摄取曲线中的这些模式伴随着蛋白质摄取速率的显著增加，这也在批摄取实验中肉眼可见。荧光峰似乎是浓度过冲，其可能部分地从对运输的电动贡献发展，所述电动贡献也增强摄取速率。电动起源的进一步证据是，该效果与高吸附剂表面电荷密度相关。结合电动效应的数学模型的预测与观测定性一致。这些研究结果表明，扩散以外的机制有助于蛋白质在带相反电荷的多孔材料中的转运，并可用于实现过程色谱中的快速摄取。
Scanning confocal fluorescence microscopy and multiphoton fluorescence microscopy were used to image the uptake of the protein lysozyme into individual ion exchange chromatography particles in a packed bed in real time. Self-sharpening concentration fronts penetrating into the particles were observed at low salt concentrations in all of the adsorbents studied, but persisted to 100 mM ionic strength only in some materials. In other adsorbents, diffuse profiles were seen at these higher salt concentrations, with the transition region exhibiting a pronounced fluorescence peak at the front at intermediate salt concentrations. These patterns in the uptake profiles are accompanied by significant increases in protein uptake rates that are also seen macroscopically in batch uptake experiments. The fluorescence peak appears to be a concentration overshoot that may develop, in part, from an electrokinetic contribution to transport that also enhances the uptake rate. Further evidence for an electrokinetic origin is that the effect is correlated with high adsorbent surface charge densities. Predictions of a mathematical model incorporating the electrokinetic effect are in qualitative agreement with the observations. These findings indicate that mechanisms other than diffusion contribute to protein transport in oppositely charged porous materials and may be exploited to achieve rapid uptake in process chromatography.