Sensitivity and speed of detection are contradicting demands that profoundly impact the electrical sensing of molecular biomarkers. Although single-molecule sensitivity can now be achieved with single-nanotube field-effect transistors, these tiny sensors, with a diameter less than 1 nm, may take hours to days to capture the molecular target at trace concentrations. Here, we show that this sensitivity-speed challenge can be addressed using covalently functionalized double-wall CNTs that form many individualized, parallel pathways between two electrodes. Each carrier that travels across the electrodes is forced to take one of these pathways that are fully gated chemically by the target–probe binding events. This sensor design allows us to electrically detect Lyme disease oligonucleotide biomarkers directly at the physiological high-salt concentrations, simultaneously achieving both ultrahigh sensitivity (as low as 1 fM) and detection speed (<15 s). This unexpectedly simple strategy may open opportunities for sensor designs to broadly achieve instant detection of trace biomarkers and real-time probing of biomolecular functions directly at their physiological states.

中文翻译：

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并行场效应纳米传感器在生理高离子强度条件下快速检测痕量生物标志物

检测的灵敏度和速度是相互矛盾的要求，深刻影响分子生物标志物的电传感。尽管现在可以通过单纳米管场效应晶体管实现单分子灵敏度，但这些直径小于 1 nm 的微型传感器可能需要数小时至数天的时间才能捕获痕量浓度的分子目标。在这里，我们表明，可以使用共价功能化双壁碳纳米管来解决这种灵敏度速度挑战，这些碳纳米管在两个电极之间形成许多个性化的平行路径。每个穿过电极的载体都被迫采取这些路径之一，这些路径由靶标-探针结合事件完全化学门控。这种传感器设计使我们能够直接在生理高盐浓度下电检测莱姆病寡核苷酸生物标志物，同时实现超高灵敏度（低至 1 fM）和检测速度（<15 s）。这种出乎意料的简单策略可能为传感器设计提供机会，广泛实现痕量生物标志物的即时检测以及直接在其生理状态下实时探测生物分子功能。