Heidt Benjamin, Rogosic Renato, Leoné Nils, Brás Eduardo J S, Cleij Thomas J, Harings Jules A W, Diliën Hanne, Eersels Kasper, van Grinsven Bart
Sensor Engineering Department, Faculty of Science and Engineering, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
Aachen-Maastricht Institute for Biobased Materials, Faculty of Science and Engineering, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
Biosensors (Basel). 2021 Oct 15;11(10):395. doi: 10.3390/bios11100395.
We demonstrate a novel way of creating three-dimensional microfluidic channels capable of following complex topographies. To this end, substrates with open channels and different geometries were 3D-printed, and the open channels were consecutively closed with a thermoplastic using a low-resolution vacuum-forming approach. This process allows the sealing of channels that are located on the surface of complex multiplanar topographies, as the thermoplastic aligns with the surface-shape (the macrostructure) of the substrate, while the microchannels remain mostly free of thermoplastic as their small channel size resists thermoplastic inflow. This new process was analyzed for its capability to consistently close different substrate geometries, which showed reliable sealing of angles >90°. Furthermore, the thermoplastic intrusion into channels of different widths was quantified, showing a linear effect of channel width and percentage of thermoplastic intrusion; ranging from 43.76% for large channels with 2 mm width to only 5.33% for channels with 500 µm channel width. The challenging sealing of substrate 'valleys', which are created when two large protrusions are adjacent to each other, was investigated and the correlation between protrusion distance and height is shown. Lastly, we present three application examples: a serpentine mixer with channels spun around a cuboid, increasing the usable surface area; a cuvette-inspired flow cell for a 2-MXP biosensor based on molecular imprinted polymers, fitting inside a standard UV/Vis-Spectrophotometer; and an adapter system that can be manufactured by one-sided injection molding and is self-sealed before usage. These examples demonstrate how this novel technology can be used to easily adapt microfluidic circuits for application in biosensor platforms.
我们展示了一种创建能够跟随复杂地形的三维微流控通道的新方法。为此，使用3D打印具有开放通道和不同几何形状的基板，然后使用低分辨率真空成型方法用热塑性塑料依次封闭开放通道。该过程允许密封位于复杂多平面地形表面上的通道，因为热塑性塑料与基板的表面形状（宏观结构）对齐，而微通道由于其小通道尺寸可抵抗热塑性塑料流入，因此大部分仍无热塑性塑料。分析了这一新工艺封闭不同基板几何形状的能力，结果表明角度>90°时密封可靠。此外，还对热塑性塑料侵入不同宽度通道的情况进行了量化，结果表明通道宽度与热塑性塑料侵入百分比呈线性关系；宽度为2mm的大通道热塑性塑料侵入率为43.76%，而通道宽度为500µm的通道热塑性塑料侵入率仅为5.33%。研究了两个大凸起相邻时形成的基板“山谷”的挑战性密封，并展示了凸起距离与高度之间的相关性。最后，我们给出了三个应用示例：一个带有围绕长方体旋转通道的蛇形混合器，增加了可用表面积；一个受比色皿启发的用于基于分子印迹聚合物的2-MXP生物传感器的流通池，可安装在标准紫外/可见分光光度计内；以及一个适配器系统，该系统可以通过单面注塑制造，并且在使用前是自密封的。这些示例展示了这种新技术如何能够轻松地使微流控电路适应生物传感器平台中的应用。
