3D Hydrodynamic Focusing in Microscale Optofluidic Channels Formed with a Single Sacrificial Layer
3D Hydrodynamic Focusing in Microscale Optofluidic Channels Formed with a Single Sacrificial Layer
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DOI：
10.3390/mi11040349
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发表时间：
2020-04-01
期刊：
影响因子：
3.4
通讯作者：
Hawkins, Aaron R.
中科院分区：
文献类型：
--
作者：
Hamilton, Erik S.;Ganjalizadeh, Vahid;Hawkins, Aaron R.
光流体装置能够检测单分子，但通过流体动力聚焦（HDF）需要更高的灵敏度和特异性。三维（3D）流体动力学聚焦实现在10 μ m规模的微通道横截面与一个单一的牺牲层。使用缓冲液包裹样品液实现HDF，需要四个流体端口通过压力驱动流动进行操作。通过蚀刻到衬底中形成的低压室或凹坑使得能够在低流速下进行体积流量比诱导的聚焦。单层设计简化了表面微加工，并将器件产量提高了1.56倍。将聚焦设计与光波导集成，并用于分析流体流中珠粒的荧光信号。发现聚焦方案的实施使珠速度和荧光信号的分布变窄，产生33%更一致的信号。在低操作真空压力下观察到储库效应，并且实现了光流体信号方差和强度之间的平衡。该设计在光流体传感器中的实现将实现更高的检测灵敏度和样品特异性。
Optofluidic devices are capable of detecting single molecules, but greater sensitivity and specificity is desired through hydrodynamic focusing (HDF). Three-dimensional (3D) hydrodynamic focusing was implemented in 10-mu m scale microchannel cross-sections made with a single sacrificial layer. HDF is achieved using buffer fluid to sheath the sample fluid, requiring four fluid ports to operate by pressure driven flow. A low-pressure chamber, or pit, formed by etching into a substrate, enables volumetric flow ratio-induced focusing at a low flow velocity. The single layer design simplifies surface micromachining and improves device yield by 1.56 times over previous work. The focusing design was integrated with optical waveguides and used in order to analyze fluorescent signals from beads in fluid flow. The implementation of the focusing scheme was found to narrow the distribution of bead velocity and fluorescent signal, giving rise to 33% more consistent signal. Reservoir effects were observed at low operational vacuum pressures and a balance between optofluidic signal variance and intensity was achieved. The implementation of the design in optofluidic sensors will enable higher detection sensitivity and sample specificity.