Florez Sergio Leonardo, Campaña Ana Lucia, Noguera M Juliana, Quezada Valentina, Fuentes Olga P, Cruz Juan C, Osma Johann F
Department of Electrical and Electronic Engineering, Universidad de Los Andes, Cra. 1E No. 19a-40, Bogota 111711, Colombia.
Department of Biomedical Engineering, Universidad de Los Andes, Cra. 1E No. 19a-40, Bogota 111711, Colombia.
Micromachines (Basel). 2022 Jun 19;13(6):970. doi: 10.3390/mi13060970.
Magnetite nanoparticles (MNPs) have attracted basic and applied research due to their immense potential to enable applications in fields as varied as drug delivery and bioremediation. Conventional synthesis schemes led to wide particle size distributions and inhomogeneous morphologies and crystalline structures. This has been attributed to the inability to control nucleation and growth processes under the conventional conditions of bulk batch processes. Here, we attempted to address these issues by scaling down the synthesis process aided by microfluidic devices, as they provide highly controlled and stable mixing patterns. Accordingly, we proposed three micromixers with different channel configurations, namely, serpentine, triangular, and a 3D arrangement with abrupt changes in fluid direction. The micromixers were first studied in silico, aided by Comsol Multiphysics to investigate the obtained mixing patterns, and consequently, their potential for controlled growth and the nucleation processes required to form MNPs of uniform size and crystalline structure. The devices were then manufactured using a low-cost approach based on polymethyl methacrylate (PMMA) and laser cutting. Testing the micromixers in the synthesis of MNPs revealed homogeneous morphologies and particle size distributions, and the typical crystalline structure reported previously. A life cycle assessment (LCA) analysis for the devices was conducted in comparison with conventional batch co-precipitation synthesis to investigate the potential impacts on water and energy consumption. The obtained results revealed that such consumptions are higher than those of the conventional process. However, they can be reduced by conducting the synthesis with reused micromixers, as new PMMA is not needed for their assembly prior to operation. We are certain that the proposed approach represents an advantageous alternative to co-precipitation synthesis schemes, in terms of continuous production and more homogeneous physicochemical parameters of interest such as size, morphologies, and crystalline structure. Future work should be directed towards improving the sustainability indicators of the micromixers' manufacturing process.
由于磁铁矿纳米颗粒（MNPs）在药物递送和生物修复等众多领域具有巨大的应用潜力，因此吸引了基础研究和应用研究。传统的合成方案导致颗粒尺寸分布广泛，形态和晶体结构不均匀。这归因于在批量间歇过程的传统条件下无法控制成核和生长过程。在这里，我们试图通过微流控设备辅助缩小合成过程来解决这些问题，因为微流控设备提供了高度可控和稳定的混合模式。因此，我们提出了三种具有不同通道配置的微混合器，即蛇形、三角形和流体方向突然变化的三维排列。首先在计算机模拟中对微混合器进行研究，借助Comsol Multiphysics软件研究获得的混合模式，进而研究它们对形成尺寸和晶体结构均匀的MNPs所需的可控生长和成核过程的潜力。然后使用基于聚甲基丙烯酸甲酯（PMMA）和激光切割的低成本方法制造这些设备。在MNPs合成中测试微混合器，结果显示出均匀的形态和颗粒尺寸分布，以及先前报道的典型晶体结构。与传统的间歇共沉淀合成相比，对这些设备进行了生命周期评估（LCA）分析，以研究对水和能源消耗的潜在影响。获得的结果表明，这些消耗高于传统工艺。然而，通过使用重复使用的微混合器进行合成可以降低消耗，因为在操作前组装时不需要新的PMMA。我们确信，就连续生产以及诸如尺寸、形态和晶体结构等更均匀的感兴趣的物理化学参数而言，所提出的方法是共沉淀合成方案的一个有利替代方案。未来的工作应致力于改善微混合器制造过程的可持续性指标。
