Integrated System Laboratory, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
Nanoscale. 2017 Jul 13;9(27):9676-9684. doi: 10.1039/c7nr01297g.
Nanoscale devices exhibiting memristive properties show great potential in a plethora of applications. In this work, memristive nanowires are presented for the first time as ideal candidates for absolutely novel, ultrasensitive, highly specific and selective drug-biosensors, also paving the way for real-time monitoring applications, in coupling with the restoration properties of DNA-aptamers. The hysteretic properties exhibited by the hereby-presented special nanodevices, modified via surface treatments, are leveraged along the complete cycle consisting of DNA-aptamer immobilization, target binding, and DNA-aptamer regeneration for successful and effective detection of Tenofovir, an antiviral drug for HIV treatment, in buffer as well as in non-diluted human serum. This results in ultrasensitive, label-free monitoring of the therapeutic compound with a limit of detection of 3.09 pM in buffer and 1.38 nM in full serum. These LODs demonstrate 10 times higher sensitivity for the in-buffer drug detection, and twice better performance for drug sensing in full human serum, ever obtained. The selectivity of the memristive biosensor for Tenofovir detection was verified through both positive and negative controls in full human serum. In addition, the DNA-aptamer regeneration character is portrayed for the first time through a memristive effect, and scanning electron microscopy throws more light on the binding mechanism efficiency through the variation of the nanodevice surface properties at the nanoscale.The results presented in this work demonstrate that the coupling of the memristive effect and aptamer regeneration provides the best ever realized nano-biosensor for drug detection also in full human serum.
具有忆阻特性的纳米器件在众多应用中具有巨大的潜力。在这项工作中,首次提出了忆阻纳米线作为理想的候选材料,用于开发全新的、超高灵敏度、高度特异性和选择性的药物生物传感器,同时也为实时监测应用铺平了道路,与 DNA 适体的修复特性相结合。本文介绍的特殊纳米器件通过表面处理进行修饰,利用其滞后特性,在整个循环中实现了成功有效的检测,该循环包括 DNA 适体的固定、目标物结合以及 DNA 适体的再生,用于在缓冲液和未稀释的人血清中检测抗病毒药物替诺福韦。这实现了对治疗化合物的超灵敏、无标记监测,在缓冲液中的检测限为 3.09 pM,在全血清中的检测限为 1.38 nM。这些检测限表明,在缓冲液中检测药物的灵敏度提高了 10 倍,在全人血清中检测药物的性能提高了 2 倍。通过在全人血清中进行正、负对照,验证了忆阻生物传感器对替诺福韦检测的选择性。此外,首次通过忆阻效应描述了 DNA 适体的再生特性,并通过纳米器件表面纳米级性质的变化,通过扫描电子显微镜更深入地研究了结合机制的效率。本工作的结果表明,忆阻效应和适体再生的结合为药物检测提供了迄今为止最先进的纳米生物传感器,即使在全人血清中也能实现。