Microfluidic devices are widely used for biomedical applications based on microscopy or other optical detection methods. However, the materials commonly used for microfabrication typically have a high refractive index relative to water, which can create artifacts at device edges and limit applicability to applications requiring high precision imaging or morphological feature detection. Here we present a soft lithography method to fabricate microfluidic devices out of MY133-V2000, a UV-curable, fluorinated polymer with low refractive index that is close to that of water (n = 1.33). The primary challenge in the use of this material (and fluorinated materials in general) is the low adhesion of the fluorinated material; we present several alternative fabrication methods we have tested to improve inter-layer adhesion. The close match between the refractive index of this material and aqueous solutions commonly used in biomedical applications enables fluorescence imaging at microchannel or other microfabricated edges without distortion. The close match in refractive index also enables quantitative phase microscopy (QPM) imaging across the full width of microchannels without error-inducing artifacts for measurement of cell biomass. Overall, our results demonstrate the utility of low-refractive index microfluidics for biological applications requiring high precision optical imaging.

中文翻译：

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折射率匹配的微流控设备的软光刻制造，可减少荧光和定量相成像中的伪影。

基于显微镜或其他光学检测方法，微流体装置被广泛用于生物医学应用。然而，通常用于微细加工的材料通常具有相对于水的高折射率，这会在器件边缘产生伪影，并限制了对需要高精度成像或形态学特征检测的应用的适用性。在这里，我们介绍一种软光刻方法，以从MY133-V2000中制造微流控器件，MY133-V2000是一种紫外线固化的氟化聚合物，其折射率接近水（n = 1.33）。使用这种材料（通常是氟化材料）的主要挑战是氟化材料的低粘附性。我们介绍了几种经过测试可以改善层间附着力的替代制造方法。该材料的折射率与生物医学应用中常用的水溶液之间的紧密匹配使得在微通道或其他微加工边缘的荧光成像不会变形。折射率的紧密匹配还可以在整个微通道的整个宽度上进行定量相显微镜（QPM）成像，而不会产生导致细胞生物量测量错误的伪影。总的来说，我们的结果证明了低折射率微流体在需要高精度光学成像的生物应用中的实用性。折射率的紧密匹配还可以在整个微通道的整个宽度上进行定量相显微镜（QPM）成像，而不会产生导致细胞生物量测量错误的伪影。总的来说，我们的结果证明了低折射率微流体在需要高精度光学成像的生物应用中的实用性。折射率的紧密匹配还可以在整个微通道的整个宽度上进行定量相显微镜（QPM）成像，而不会产生导致细胞生物量测量错误的伪影。总的来说，我们的结果证明了低折射率微流体在需要高精度光学成像的生物应用中的实用性。