We analyze the transport of 25 nm polystyrene nanoparticles through a microfluidic geometry housing a microtoroidal whispering gallery mode (WGM) sensor, taking into account diffusion, convection and optical forces. In particular, we look at the effects of tightly confining the flow of nanoparticles near the microtoroid’s equatorial rim, and calculate the average nanoparticle detection time as well as the total yield for passage of a 1 L sample. Compared to purely diffusive transport, flow rates on the order of 2 nL min give yield enhancements of up to 15 , with nanoparticles being detected every 12 s. Even shorter detection times (1.2 s) can be achieved, but at the expense of lower yield. The sensor’s transport properties are further improved due to gradient optical forces exerted on the nanoparticles.

中文翻译：

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回音壁模式生物传感器的产量提高：微流体和光学力

我们分析了 25 nm 聚苯乙烯纳米粒子通过微流体几何结构的传输，该几何结构包含微环形回音壁模式 (WGM) 传感器，同时考虑到扩散、对流和光学力。特别是，我们研究了在微环的赤道边缘附近严格限制纳米颗粒流动的影响，并计算平均纳米颗粒检测时间以及通过 1 L 样品的总产量。与纯粹的扩散传输相比，大约 2 nL min 的流速使产量提高了 15%，每 12 秒检测到一次纳米颗粒。甚至可以实现更短的检测时间 (1.2 s)，但代价是产量较低。由于施加在纳米颗粒上的梯度光学力，传感器的传输特性得到进一步改善。