Molinski John H, Parwal Siddhant, Zhang John X J
Thayer School of Engineering at Dartmouth, Hanover, NH, 03755, USA.
Dartmouth Cancer Center, Dartmouth Health, Lebanon, NH, 03766, USA.
Small Methods. 2024 Dec;8(12):e2400388. doi: 10.1002/smtd.202400388. Epub 2024 Jul 14.
Efficient isolation and patterning of biomolecules is a vital step within sample preparation for biomolecular analysis, with numerous diagnostic and therapeutic applications. For exosomes, nanoscale lipid-bound biomolecules, efficient isolation is challenging due to their minute size and resultant behavior within biofluids. This study presents a method for the rapid isolation and patterning of magnetically tagged exosomes via rationally designed micromagnets. Micromagnet fabrication utilizes a novel, scalable, and high-throughput laser-based fabrication approach that enables patterning at microscale lateral resolution (<50 µm) without lithographic processing and is agnostic to micromagnet geometry. Laser-based processing allows for flexible and tunable device configurations, and herein magnetophoretic capture within both an open-air microwell and an enclosed microfluidic system is demonstrated. Patterned micromagnets enhance localized gradient fields throughout the fluid medium, resulting in rapid and high efficiency magnetophoretic separation, with capture efficiencies nearing 70% after just 1s within open-air microwells, and throughputs upward of 3 mL h within enclosed microfluidic systems. Using this microchip architecture, immunomagnetic exosome isolation and patterning directly from undiluted plasma samples is further achieved. Lastly, a FEA-based modeling workflow is introduced to characterize and optimize micromagnet unit cells, simulating magnetophoretic capture zones for a given micromagnet geometry.
生物分子的高效分离和图案化是生物分子分析样品制备中的关键步骤，具有众多诊断和治疗应用。对于外泌体这种纳米级脂质结合生物分子，由于其微小尺寸以及在生物流体中的行为，高效分离具有挑战性。本研究提出了一种通过合理设计的微磁体快速分离和图案化磁性标记外泌体的方法。微磁体制造采用了一种新颖、可扩展且高通量的基于激光的制造方法，该方法能够在无需光刻工艺的情况下以微米级横向分辨率（<50 µm）进行图案化，并且与微磁体几何形状无关。基于激光的加工允许灵活且可调的器件配置，本文展示了在开放式微孔和封闭式微流体系统中的磁泳捕获。图案化的微磁体增强了整个流体介质中的局部梯度场，从而实现快速且高效的磁泳分离，在开放式微孔中仅1秒后捕获效率就接近70%，在封闭式微流体系统中的通量超过3 mL/h。使用这种微芯片架构，还进一步实现了直接从未稀释的血浆样品中免疫磁分离和图案化外泌体。最后，引入了基于有限元分析（FEA）的建模工作流程来表征和优化微磁体单元，模拟给定微磁体几何形状的磁泳捕获区域。
