3D hydrodynamic focusing was implemented with channel cross-section dimensions smaller than 10 μm. Microchannels were formed using sacrificial etching of two photoresist layers on a silicon wafer. The photoresist forms a plus-shaped prismatic focusing fluid junction which was coated with plasma-enhanced chemical-vapor-deposited oxide. Buffer fluid carried to the focusing junction envelopes an intersecting sample fluid, resulting in 3D focusing of the sample stream. The design requires four fluid ports and operates across a wide range of fluid velocities through pressure-driven flow. The focusing design was integrated with optical waveguides to interrogate fluorescing particles and confirm 3D focusing. Particle diffusion away from a focused stream was characterized.

以小于 10 μm 的通道横截面尺寸实现 3D 流体动力学聚焦。使用牺牲蚀刻硅晶片上的两个光刻胶层来形成微通道。光致抗蚀剂形成正形棱柱聚焦流体结，其涂有等离子体增强化学气相沉积氧化物。输送到聚焦接头的缓冲液包裹着相交的样品液，从而实现样品流的 3D 聚焦。该设计需要四个流体端口，并通过压力驱动的流动在广泛的流体速度范围内运行。聚焦设计与光波导集成以询问荧光颗粒并确认 3D 聚焦。表征远离聚焦流的粒子扩散。