Abstract The removal of non-specific binding on the sensor surface represents a major challenge for rapid and sensitive biosensing. The stimulation of an electrohydrodynamic (EHD) fluid flow in proximity to the biosensor surface can improve sensor performance. The EHD fluid flow is depending on the geometry of electrodes. Here, the effect of electrode diameter and spacing of asymmetric circular electrodes is investigated for the capability to stimulate fluid flow and capture model beads and protein biomarker. Six geometries with diameters of 30–1000 μm and spacing of 200–1500 μm were systematically studied. Capture of target beads in excess of non-target beads showed higher target bead capture with increase in electrode diameter. The target bead capture was 4 × improved and displacement of non-target reduced by factor 2. The electrode with the highest bead capture was then used to establish an immunoassay for detection of novel cancer immunotherapy biomarker CD28 fortified in buffer and fetal bovine serum. The EHD parameters for optimal CD28 capture were different to the bead capture parameters. This indicated that, depending on the binding strength of target to affinity tag, the EHD parameters could be tailored to provide ideal capture conditions. The use of EHD significantly reduced the assay time by 92.4%, removed non-target binding by a factor of 3.5 compared to static incubation, and was sensitive to detect as low as 20 pg mL − 1 CD28. In a proof-of-concept study, the potential of the EHD-assisted immunoassay for point of care application was demonstrated using a simple naked eye read-out.

中文翻译：

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用于增强生物传感的电流体动力学流体流动的几何优化

摘要 去除传感器表面的非特异性结合是快速灵敏生物传感的主要挑战。刺激生物传感器表面附近的电流体动力学 (EHD) 流体流动可以提高传感器性能。EHD 流体流动取决于电极的几何形状。在这里，研究了电极直径和不对称圆形电极间距的影响，以刺激流体流动和捕获模型珠子和蛋白质生物标志物的能力。系统地研究了直径为 30-1000 μm、间距为 200-1500 μm 的六种几何形状。超过非目标珠的目标珠的捕获随着电极直径的增加显示出更高的目标珠捕获。目标珠的捕获提高了 4 倍，非目标的位移减少了 2 倍。然后使用具有最高珠捕获率的电极建立免疫测定法，用于检测在缓冲液和胎牛血清中强化的新型癌症免疫治疗生物标志物 CD28。最佳 CD28 捕获的 EHD 参数与珠子捕获参数不同。这表明，根据目标与亲和标签的结合强度，可以定制 EHD 参数以提供理想的捕获条件。与静态孵育相比，EHD 的使用显着减少了 92.4% 的检测时间，消除了 3.5 倍的非靶标结合，并且对检测低至 20 pg mL - 1 CD28 的检测敏感。在概念验证研究中，使用简单的肉眼读数证明了 EHD 辅助免疫测定在护理点应用中的潜力。