Hejazian Majid, Darmanin Connie, Balaur Eugeniu, Abbey Brian
ARC Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University VIC 3086 Australia
RSC Adv. 2020 Apr 21;10(27):15694-15701. doi: 10.1039/d0ra00232a.
Serial femtosecond crystallography (SFX) methods used at X-ray free electron lasers (XFELs) offer a range of new opportunities for structural biology. A crucial component of SFX experiments is sample delivery. Microfluidic devices can be employed in SFX experiments to precisely deliver microcrystals to the X-ray beam and to trigger molecular dynamics rapid mix-and-inject measurements. Here, for the first time, we have developed a process based on high-resolution photolithography using SU8 on glass to fabricate microfluidic mix-and-inject devices. In order to characterise these devices a broad range of flow rates are used and the mixing and jetting response of the devices monitored. We observe that a stable jet is formed using these devices when injecting DI-water. Three different jetting regimes, liquid column, ribbon, and cylindrical jet, were observed. Furthermore, fluorescence experiments confirm that rapid and uniform mixing of the two injected solutions is possible using these devices indicating that they could be used to probe molecular dynamics on sub-microsecond timescales.
在X射线自由电子激光（XFEL）上使用的串行飞秒晶体学（SFX）方法为结构生物学提供了一系列新机遇。SFX实验的一个关键组成部分是样品递送。微流控装置可用于SFX实验，以将微晶精确递送至X射线束，并触发分子动力学快速混合和注入测量。在此，我们首次开发了一种基于在玻璃上使用SU8进行高分辨率光刻的工艺，以制造微流控混合和注入装置。为了表征这些装置，使用了广泛的流速范围，并监测装置的混合和喷射响应。我们观察到，在注入去离子水时，使用这些装置会形成稳定的射流。观察到三种不同的喷射模式，即液柱、带状和圆柱形射流。此外，荧光实验证实，使用这些装置可以使两种注入溶液快速且均匀地混合，这表明它们可用于探测亚微秒时间尺度上的分子动力学。
