Partnership for Soft Condensed Matter (PSCM), ESRF - The European Synchrotron, 71 avenue des Martyrs, 38043 Grenoble, France.
ESRF- The European Synchrotron, 71 avenue des Martyrs, 38043 Grenoble, France.
Lab Chip. 2020 Nov 10;20(22):4128-4140. doi: 10.1039/d0lc00767f.
The use of microfluidics on synchrotron X-ray beamlines represents an advanced sample preparation and delivery platform for state-of-the-art X-ray characterization of micro-samples. The recent developments of 3D printing technologies have opened possibilities for rapid fabrication of complex microfluidic devices. One of the major challenges in 3D printing of microfluidic devices using a digital light processing (DLP) desktop printer is that the static liquid resin trapped in the channels, once the "ceiling" is printed, still receives small doses of light through the subsequently printed layers. This easily triggers partial polymerisation of the resin which impedes its flushing out of the channels after completion of the printing session. We show here that it is possible to gain better control over the resin polymerisation and improve the quality of the microfluidic devices by efficiently reducing the penetration depth of the UV LED light through wavelength selection combined with a careful choice of absorber and photo-initiator materials. We produced and tested several structures using a slightly modified desktop printer at 385 nm wavelength with 37 × 37 μm2 pixel resolution at a printed layer thickness of 25 μm. The structures include particle filters, mixers, droplet generators and droplet storage traps with features below 100 μm. We demonstrate crystallisation of model inorganic and organic compounds in trapped droplets and assess the feasibility of in-device X-ray diffraction experiments. This research opens the path for the use of 3D printed microfluidic devices on X-ray beamlines.
在同步加速器 X 射线光束线上使用微流控技术代表了一种先进的样品制备和输送平台，可用于对微样本进行最先进的 X 射线特性分析。最近 3D 打印技术的发展为快速制造复杂的微流控设备开辟了可能性。使用数字光处理（DLP）台式打印机对微流控设备进行 3D 打印的主要挑战之一是，一旦打印了“天花板”，被困在通道中的静态液体树脂仍然会通过随后打印的层接收到少量的光。这很容易引发树脂的部分聚合，从而阻碍其在打印会话完成后从通道中冲洗出来。我们在这里表明，通过波长选择结合仔细选择吸收剂和光引发剂材料，有效地降低 UV LED 光的穿透深度，可以更好地控制树脂聚合，并提高微流控设备的质量。我们使用经过略微修改的桌面打印机在 385nm 波长下以 37×37μm2 的像素分辨率和 25μm 的打印层厚度生产并测试了几种结构。这些结构包括粒径过滤器、混合器、液滴发生器和具有低于 100μm 特征的液滴储存陷阱。我们在被困液滴中演示了模型无机和有机化合物的结晶，并评估了在设备内进行 X 射线衍射实验的可行性。这项研究为在 X 射线光束线上使用 3D 打印微流控设备开辟了道路。
