Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
Department of Radiology, Stanford University, Stanford, CA 94305, USA.
Sci Adv. 2023 Sep 22;9(38):eadh4978. doi: 10.1126/sciadv.adh4978.
We present a generalizable approach for designing biosensors that can continuously detect small-molecule biomarkers in real time and without sample preparation. This is achieved by converting existing antibodies into target-responsive "antibody-switches" that enable continuous optical biosensing. To engineer these switches, antibodies are linked to a molecular competitor through a DNA scaffold, such that competitive target binding induces scaffold switching and fluorescent signaling of changing target concentrations. As a demonstration, we designed antibody-switches that achieve rapid, sample preparation-free sensing of digoxigenin and cortisol in undiluted plasma. We showed that, by substituting the molecular competitor, we can further modulate the sensitivity of our cortisol switch to achieve detection at concentrations spanning 3.3 nanomolar to 3.3 millimolar. Last, we integrated this switch with a fiber optic sensor to achieve continuous sensing of cortisol in a buffer and blood with <5-min time resolution. We believe that this modular sensor design can enable continuous biosensor development for many biomarkers.
我们提出了一种可推广的方法来设计生物传感器，这种传感器可以实时、无需样品制备地连续检测小分子生物标志物。这是通过将现有的抗体转化为目标响应的“抗体开关”来实现的，这种开关可以实现连续的光学生物传感。为了设计这些开关，抗体通过 DNA 支架与分子竞争物连接，使得竞争性目标结合诱导支架转换和目标浓度变化的荧光信号。作为演示，我们设计了抗体开关，可实现对未稀释血浆中的地高辛和皮质醇的快速、无需样品制备的检测。我们表明，通过替换分子竞争物，我们可以进一步调节我们的皮质醇开关的灵敏度，以实现 3.3 纳摩尔到 3.3 毫摩尔浓度范围内的检测。最后，我们将这个开关与光纤传感器集成，以实现缓冲液和血液中皮质醇的连续传感，时间分辨率小于 5 分钟。我们相信，这种模块化的传感器设计可以为许多生物标志物的连续生物传感器开发提供可能。
