Amadeo Filippo, Mukherjee Prithviraj, Gao Hua, Zhou Jian, Papautsky Ian
Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA.
Micromachines (Basel). 2021 Nov 13;12(11):1392. doi: 10.3390/mi12111392.
Fabrication of microfluidic devices by soft lithography is by far the most popular approach due to its simplicity and low cost. The approach relies on casting of elastomers, such as polydimethylsiloxane (PDMS), on masters fabricated from photoresists on silicon substrates. These masters, however, can be expensive, complicated to fabricate, and fragile. Here we describe an optimized replica molding approach to preserve the original masters by heat molding of polycarbonate (PC) sheets on PDMS molds. The process is faster and simpler than previously reported methods and does not result in a loss of resolution or aspect ratio for the features. The generated PC masters were used to successfully replicate a wide range of microfluidic devices, including rectangular channels with aspect ratios from 0.025 to 7.3, large area spiral channels, and micropost arrays with 5 µm spacing. Moreover, fabrication of rounded features, such as semi-spherical microwells, was possible and easy. Quantitative analysis of the replicated features showed variability of <2%. The approach is low cost, does not require cleanroom setting or hazardous chemicals, and is rapid and simple. The fabricated masters are rigid and survive numerous replication cycles. Moreover, damaged or missing masters can be easily replaced by reproduction from previously cast PDMS replicas. All of these advantages make the PC masters highly desirable for long-term preservation of soft lithography masters for microfluidic devices.
通过软光刻制造微流控器件是目前最受欢迎的方法，因为它简单且成本低。该方法依赖于将弹性体（如聚二甲基硅氧烷（PDMS））浇铸在由硅基板上的光刻胶制成的母版上。然而，这些母版可能成本高昂、制造复杂且易碎。在此，我们描述一种优化的复制成型方法，通过在PDMS模具上热成型聚碳酸酯（PC）片来保存原始母版。该过程比先前报道的方法更快、更简单，并且不会导致特征的分辨率或纵横比损失。生成的PC母版成功用于复制各种微流控器件，包括纵横比从0.025到7.3的矩形通道、大面积螺旋通道以及间距为5 µm的微柱阵列。此外，制造圆形特征（如半球形微孔）是可行且容易的。对复制特征的定量分析显示变异性小于2%。该方法成本低，不需要洁净室环境或危险化学品，且快速简单。制造的母版坚固耐用，可经受多次复制循环。此外，损坏或缺失的母版可以通过从先前浇铸的PDMS复制品进行复制轻松替换。所有这些优点使得PC母版非常适合长期保存微流控器件的软光刻母版。
