College of Engineering, North Dakota State University, Fargo, ND 58102, USA.
College of Engineering and Mines, University of North Dakota, Grand Forks, ND 58202, USA.
Sensors (Basel). 2023 May 30;23(11):5193. doi: 10.3390/s23115193.
Radio frequency (RF) biosensors are an expanding field of interest because of the ability to design noninvasive, label-free, low-production-cost sensing devices. Previous works identified the need for smaller experimental devices, requiring nanoliter to milliliter sampling volumes and increased capability of repeatable and sensitive measurement capability. The following work aims to verify a millimeter-sized, microstrip transmission line biosensor design with a microliter well operating on a broadband radio frequency range of 1.0-17.0 GHz. Three successive experiments were performed to provide evidence for (1) repeatability of measurements after loading/unloading the well, (2) sensitivity of measurement sets, and (3) methodology verification. Materials under test (MUTs) loaded into the well included deionized water, Tris-EDTA buffer, and lambda DNA. S-parameters were measured to determine interaction levels between the radio frequencies and MUTs during the broadband sweep. MUTs increasing in concentration were repeatably detected and demonstrated high measurement sensitivity, with the highest error value observed being 0.36%. Comparing Tris-EDTA buffer versus lambda DNA suspended in Tris-EDTA buffer suggests that introducing lambda DNA into the Tris-EDTA buffer repeatably alters S-parameters. The innovative aspect of this biosensor is that it can measure interactions of electromagnetic energy and MUTs in microliter quantities with high repeatability and sensitivity.
射频（RF）生物传感器是一个不断发展的研究领域，因为它能够设计出非侵入性、无标记、低成本的传感设备。以前的工作已经确定了需要更小的实验设备的需求，这需要纳升到毫升级的采样体积，并提高可重复性和灵敏测量能力。以下工作旨在验证一种毫米级、微带传输线生物传感器设计，该设计具有微升井，可在 1.0-17.0GHz 的宽带射频范围内运行。进行了三个连续的实验，以提供以下证据：（1）在加载/卸载井后测量的可重复性；（2）测量集的灵敏度；（3）方法验证。加载到井中的测试材料（MUT）包括去离子水、Tris-EDTA 缓冲液和 lambda DNA。测量 S 参数以确定宽带扫描过程中射频与 MUT 之间的相互作用水平。浓度增加的 MUT 可重复检测，并表现出高测量灵敏度，观察到的最高误差值为 0.36%。将 Tris-EDTA 缓冲液与悬浮在 Tris-EDTA 缓冲液中的 lambda DNA 进行比较表明，将 lambda DNA 引入 Tris-EDTA 缓冲液中可重复地改变 S 参数。该生物传感器的创新之处在于，它可以以高重复性和灵敏度测量微升量的电磁能和 MUT 之间的相互作用。
