Shen Fengshan, Yu Yan, Li Yuexuan, Feng Hongtao, Wu Tianzhun, Chen Yan
CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences Shenzhen China
RSC Adv. 2021 Oct 27;11(55):34660-34668. doi: 10.1039/d1ra06173a. eCollection 2021 Oct 25.
The ability to locally modulate the magnetic field distribution is a prerequisite for efficient manipulation in magnetic force-based microfluidic devices. Here, we report a simple, robust, and fast fabrication method of magnetic microstructures for locally modulating magnetic fields. In the proposed method, a photosensitive magnetic composite consisting of carbonyl-iron microparticles in a poly(ethylene glycol) diacrylate (PEGDA) matrix was utilized to photolithographically fabricate magnetic microstructures. The magnetic behavior of the composite was first evaluated, and then various complicated patterns were fabricated on a glass slide within a few minutes. To demonstrate the capability of magnetic microstructures as a magnetic field concentrator, magnetic microstructures with different orientations to the external magnetic field were designed and fabricated, such as square arrays and grid-like magnetic microstructures. The modulated magnetic fields from such magnetic microstructures were numerically analyzed and then experimentally validated by trapping magnetic hydrogel beads. Further, the magnetically labeled cells were applied to the magnetic microstructures to prove the possibility of cell confinement magnetic guidance in regions that exhibit enhanced magnetic field gradients. Overall, the proposed approach facilitates simple and fast fabrication of soft magnetic microstructures for microscale modulation of magnetic fields, which exhibits an immense application potential in magnetic force-based microfluidic techniques.
局部调节磁场分布的能力是基于磁力的微流控装置中进行有效操控的前提条件。在此，我们报告一种用于局部调节磁场的磁性微结构的简单、稳健且快速的制造方法。在所提出的方法中，一种由聚（乙二醇）二丙烯酸酯（PEGDA）基质中的羰基铁微粒组成的光敏磁性复合材料被用于通过光刻制造磁性微结构。首先评估了该复合材料的磁行为，然后在几分钟内在载玻片上制造了各种复杂图案。为了证明磁性微结构作为磁场集中器的能力，设计并制造了与外部磁场具有不同取向的磁性微结构，例如方形阵列和网格状磁性微结构。对这种磁性微结构产生的调制磁场进行了数值分析，然后通过捕获磁性水凝胶珠进行了实验验证。此外，将磁性标记的细胞应用于磁性微结构，以证明在呈现增强磁场梯度的区域中细胞限制和磁性引导的可能性。总体而言，所提出的方法有助于简单快速地制造用于微尺度磁场调制的软磁性微结构，这在基于磁力的微流控技术中具有巨大的应用潜力。
