Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Lab Chip. 2018 Mar 13;18(6):890-901. doi: 10.1039/c7lc00951h.
Wider use and adaptation of microfluidics is hindered by the infrastructure, knowledge, and time required to build prototype systems, especially when multiple fluid operations and measurements are required. As a result, 3D printing of microfluidics is attracting interest, yet cannot readily achieve the feature size, smoothness, and optical transparency needed for many standard microfluidic systems. Herein we present a new approach to the design and construction of high-precision modular microfluidics, using standard injection-molded blocks that are modified using micromilling and assembled via elastically averaged contacts. Desktop micromilling achieves channel dimensions as small as 50 μm depth and 150 μm width and adhesive films seal channels to allow internal fluid pressure of >400 kPa. Elastically averaged connections between bricks result in a mechanical locating repeatability of ∼1 μm, enabling fluid to pass between bricks via an O-ring seal with >99.9% reliability. We demonstrated and tested block-based systems for generating droplets at rates above 9000 min and COV <3%, and integrated optical sensors. We also show how blocks can be used to build easily reconfigurable interfaces with glass microfluidic devices and imaging hardware. Microfluidic bricks fabricated by FDM and SLA 3D printing cannot achieve the dimensional quality of molded bricks, yet 3D printing allows customized bricks to be integrated with standard LEGOs. Our approach enables a wide variety of modular microfluidic units to be built using a widely available, cost-effective platform, encouraging use in both research and education.
微流控的广泛应用和适应性受到构建原型系统所需的基础设施、知识和时间的限制，尤其是当需要进行多种流体操作和测量时。因此，微流控的 3D 打印技术引起了人们的兴趣，但它不能轻易实现许多标准微流控系统所需的特征尺寸、平滑度和光学透明度。在此，我们提出了一种新的高精度模块化微流控设计和构建方法，使用经过微铣削修改的标准注塑块，并通过弹性平均接触进行组装。桌面微铣削可实现小至 50μm 深度和 150μm 宽度的通道尺寸，并使用粘性薄膜密封通道，以允许内部流体压力超过 400kPa。砖块之间的弹性平均连接导致机械定位重复性约为 1μm，从而使流体能够通过 O 形圈密封在砖块之间可靠地传递，可靠性超过 99.9%。我们展示并测试了基于块状系统的微流控，其生成液滴的速率超过 9000 min，COV<3%，并集成了光学传感器。我们还展示了如何使用块状物构建与玻璃微流控器件和成像硬件易于重新配置的接口。FDM 和 SLA 3D 打印制造的微流控砖无法达到注塑砖的尺寸质量，但 3D 打印允许定制砖块与标准乐高积木集成。我们的方法可以使用广泛可用、具有成本效益的平台构建各种模块化微流控单元，鼓励在研究和教育中使用。
