Department of Nano Manufacturing Technology, Korea Institute of Machinery and Materials (KIMM), Daejeon 34103, Republic of Korea.
Department of Nanomechatronics, University of Science and Technology, Daejeon 34113, Republic of Korea.
Langmuir. 2023 Feb 14;39(6):2274-2280. doi: 10.1021/acs.langmuir.2c02879. Epub 2023 Jan 30.
Nanogap biosensors have emerged as promising platforms for detecting and measuring biochemical substances at low concentrations. Although the nanogap biosensors provide high sensitivity, low limit of detection (LOD), and enhanced signal strength, it requires arduous fabrication processes and costly equipment to obtain micro/nanoelectrodes with extremely narrow gaps in a controlled manner. In this work, we report the novel design and fabrication processes of vertical nanogap structures that can electrically detect and quantify low-concentration biochemical substances. Approximately 40 nm gaps are facilely created by magnetically assembling antibody-coated nanowires onto a nanodisk patterned between a pair of microelectrodes. Analyte molecules tagged with conductive nanoparticles are captured and bound to nanowires and bridge over the nanogaps, which consequently causes an abrupt change in the electrical conductivity between the microelectrodes. Using biotin and streptavidin as model antibodies and analytes, we demonstrated that our nanogap biosensors can effectively measure the protein analytes with the LOD of ∼18 pM. The outcome of this research could inspire the design and fabrication of nanogap devices and nanobiosensors, and it would have a broad impact on the development of microfluidics, biochips, and lab-on-a-chip architectures.
纳诺间隙生物传感器已成为在低浓度下检测和测量生化物质的有前途的平台。尽管纳诺间隙生物传感器提供了高灵敏度、低检测限（LOD）和增强的信号强度，但它需要艰苦的制造工艺和昂贵的设备才能以可控的方式获得具有极窄间隙的微/纳米电极。在这项工作中，我们报告了垂直纳诺间隙结构的新颖设计和制造工艺，这些结构可以电检测和量化低浓度的生化物质。通过将涂有抗体的纳米线通过磁性组装到一对微电极之间的纳米盘中，可以轻松地产生约 40nm 的间隙。标记有导电纳米颗粒的分析物分子被捕获并结合到纳米线上，并跨越纳诺间隙，从而导致微电极之间的电导率发生突然变化。使用生物素和链霉亲和素作为模型抗体和分析物，我们证明了我们的纳诺间隙生物传感器可以有效地测量具有约 18pM 的 LOD 的蛋白质分析物。这项研究的结果可以激发纳诺间隙器件和纳诺生物传感器的设计和制造，并且将对微流控、生物芯片和片上实验室架构的发展产生广泛影响。
