Department of Mechanical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
Nanoscale. 2018 Aug 2;10(30):14421-14431. doi: 10.1039/c7nr07669j.
Despite the unique advantages of nanochannels imparted by their small size, their utility is limited by the lack of affordable and versatile fabrication methods. Moreover, nanochannel-incorporated fluidic devices require micro-sized conduit integration for efficient access of liquid samples. In this study, a simple and cost-effective fabrication method for mixed-scale channel networks via hot-embossing of poly(methyl methacrylate) (PMMA) using a carbon stamp is demonstrated. Due to its high rigidity, PMMA ensures collapse-free channel fabrication. The carbon stamp is fabricated using only batch microfabrication and has a convex architecture that allows the fabrication of a complex channel network via a single imprinting process. In addition, the microchannels are connected to nanochannels via three-dimensional (3D) microfunnels that serve as single-particle-entrapment chambers, ensuring smooth transport of samples into the nanochannels. Owing to the 3D geometry of the microfunnels and the small size of the nanochannels, a solute gradient can be generated locally at the microfunnel. This local solute gradient enables the entrapment of microparticles at the microfunnels via diffusiophoresis, which can manipulate the particle motion in a controllable manner, without any external equipment or additional electrode integration into the channels. To the best of our knowledge, this is the first report of diffusiophoresis-based single-particle entrapment.
尽管纳米通道具有尺寸小带来的独特优势，但由于缺乏经济实惠且用途广泛的制造方法，其应用受到限制。此外，纳米通道流体装置需要微通道集成才能有效地处理液体样品。在这项研究中，展示了一种通过热压印聚甲基丙烯酸甲酯（PMMA）制造混合尺度通道网络的简单且具有成本效益的方法，使用的碳压印模板是通过批量微加工制造的，具有凸面结构，允许通过单次压印过程制造复杂的通道网络。此外，微通道通过三维（3D）微漏斗与纳米通道相连，微漏斗充当单颗粒捕获室，确保样品顺利进入纳米通道。由于微漏斗的 3D 几何形状和纳米通道的小尺寸，可以在微漏斗处局部产生溶质梯度。这种局部溶质梯度可以通过扩散电泳将微颗粒捕获在微漏斗处，从而以可控的方式操纵颗粒的运动，而无需任何外部设备或将额外的电极集成到通道中。据我们所知，这是首次报道基于扩散电泳的单颗粒捕获。
