Sarwar M Sulaiman, Simon Ursula, Dimartino Simone
Institute for Bioengineering, The School of Engineering, The University of Edinburgh, Edinburgh EH9 3DW, UK.
Institute for Bioengineering, The School of Engineering, The University of Edinburgh, Edinburgh EH9 3DW, UK.
J Chromatogr A. 2021 Jun 7;1646:462125. doi: 10.1016/j.chroma.2021.462125. Epub 2021 Apr 1.
3D printing has recently found application in chromatography as a means to create ordered stationary phases with improved separation efficiency. Currently, 3D printed stationary phases are limited by the lack of 3D printing materials suitable for chromatographic applications, and require a strict compromise in terms of desired resolution, model size and the associated print time. Modelling of mass transfer in 3D printed monoliths is also fundamental to understand and further optimise separation performance of 3D printed stationary phases. In this work, a novel 3D printing material was formulated and employed to fabricate monolithic cation exchangers (CEXs) with carboxyl functionalities. CEXs were printed with ligand densities of 0.7, 1.4, 2.1 and 2.8 mmol/g and used in batch adsorption experiments with lysozyme as model protein. All CEXs demonstrated high binding strength towards lysozyme, with maximum binding capacities of up to 108 mg/mL. The experimental results were described using mass transfer models based on lumped pore diffusion and lumped solid diffusion mechanisms adapted to reflect the complex geometry of the 3D printed monoliths. An exact 3D model as well as less computationally demanding 1D and 2D approximations were evaluated in terms of their quality to capture the experimental trend of batch adsorption kinetic data. Overall, the model results indicate that mass transfer in the fabricated CEXs is mostly controlled by pore diffusion at high protein concentrations in the mobile phase, with solid diffusion becoming important at low protein concentrations. Also, the kinetic data were approximated equally well by both the full 3D model as well as the 2D approximation, indicating leaner mathematical models of lower dimensionality can be employed to describe mass transfer in complex three dimensional geometries. We believe this work will help spur the development of 3D printable materials for separations and aid in the development of quantitative platforms to evaluate and optimise the performance of 3D printed monoliths.
3D打印最近在色谱法中得到应用，作为一种创建具有更高分离效率的有序固定相的手段。目前，3D打印固定相受到缺乏适用于色谱应用的3D打印材料的限制，并且在所需分辨率、模型尺寸和相关打印时间方面需要严格的权衡。对3D打印整体柱中的传质进行建模对于理解和进一步优化3D打印固定相的分离性能也至关重要。在这项工作中，一种新型的3D打印材料被配制并用于制造具有羧基官能团的整体阳离子交换剂（CEXs）。CEXs以0.7、1.4、2.1和2.8 mmol/g的配体密度进行打印，并用于以溶菌酶为模型蛋白的批量吸附实验。所有CEXs对溶菌酶都表现出高结合强度，最大结合容量高达108 mg/mL。实验结果使用基于集总孔扩散和集总固体扩散机制的传质模型进行描述，这些机制经过调整以反映3D打印整体柱的复杂几何形状。根据其捕捉批量吸附动力学数据实验趋势的质量，评估了精确的3D模型以及计算要求较低的1D和2D近似模型。总体而言，模型结果表明，在流动相中高蛋白浓度下，制造的CEXs中的传质主要受孔扩散控制，而在低蛋白浓度下固体扩散变得重要。此外，完整的3D模型和2D近似模型对动力学数据的近似效果相同，这表明可以采用维度较低的更简洁数学模型来描述复杂三维几何形状中的传质。我们相信这项工作将有助于推动用于分离的3D可打印材料的开发，并有助于开发定量平台来评估和优化3D打印整体柱的性能。
