MicroRNAs and other small oligonucleotides in biofluids are promising disease biomarkers, yet conventional assays require complex processing steps that are unsuitable for point-of-care testing or for implantable or wearable sensors. Single-walled carbon nanotubes are an ideal material for implantable sensors, owing to their emission in the near-infrared spectral region, photostability and exquisite sensitivity. Here, we report an engineered carbon-nanotube-based sensor capable of real-time optical quantification of hybridization events of microRNA and other oligonucleotides. The mechanism of the sensor arises from competitive effects between displacement of both oligonucleotide charge groups and water from the nanotube surface, which result in a solvatochromism-like response. The sensor, which allows for detection via single-molecule sensor elements and for multiplexing by using multiple nanotube chiralities, can monitor toehold-based strand-displacement events, which reverse the sensor response and regenerate the sensor complex. We also show that the sensor functions in whole urine and serum, and can non-invasively measure DNA and microRNA after implantation in live mice.

生物流体中的MicroRNA和其他小寡核苷酸是有前途的疾病生物标志物，然而常规测定需要复杂的处理步骤，这些步骤不适用于即时检验或植入式或可穿戴式传感器。单壁碳纳米管由于在近红外光谱区域中的发射，光稳定性和出色的灵敏度而成为植入式传感器的理想材料。在这里，我们报告基于工程碳纳米管的传感器，能够实时光学定量的microRNA和其他寡核苷酸的杂交事件。传感器的机理来自寡核苷酸电荷基团和纳米管表面的水置换之间的竞争效应，这导致类似溶剂变色反应。传感器 它可以通过单分子传感器元件进行检测，并可以通过使用多个纳米管手性进行多路复用，它可以监视基于脚趾的链位移事件，从而改变传感器响应并重新生成传感器复合体。我们还表明，传感器在全尿和血清中起作用，并且可以在植入活小鼠后以非侵入性方式测量DNA和microRNA。