Kar Piyush, Shankar Karthik
Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, T6G 2V4, Canada.
J Nanosci Nanotechnol. 2013 Jul;13(7):4473-96. doi: 10.1166/jnn.2013.7771.
The simplicity of synthesis of deterministically positioned inorganic semiconductor nanorods (NRs) and nanotubes (NTs) coupled with their chemical stability, high surface area, controllable optical properties and tunable surface functionality, have sparked worldwide research efforts towards biodiagnostic applications. Biosensors based on oriented and aligned one-dimensional (1-D) inorganic semiconductor nanostructures have demonstrated remarkable detection sensitivity, high throughput and label-free operability. In comparison to suspensions of nanoparticles and discrete randomly oriented nanowires, nanowire (NW) and nanotube arrays offer continuous charge transport pathways, a major advantage for all-electrical detection and in exploiting electrokinetic effects. We review highly sensitive biosensors based on oriented and aligned NTs/NRs/NWs employing conventional detection methods, inclusive of fluorescence, electrochemistry and electromechanical sensing as well as detection methods unique to nanowires such as field-effect transistors. Entirely new types of sensing applications such as the impaling of living cells to monitor cellular events in situ, and substrates with electrically controlled wetting for surface-assisted laser desorption and ionization are emerging to take advantage of the unique properties of nanowire arrays. Concurrently, we explain the semiconductor materials and architectures employed, and the functionalization procedures used to construct the biosensors. Aligned semiconductor array-based approaches are critically examined in relation to prevailing technologies to get a sense of the exclusive niches that nanotube/nanorod array biosensors inhabit. The versatility of the detection principles that nanowire/nanotube arrays are compatible with are enabling hybrid approaches where combinations of detection methods are used. Such advantages offset the complexity associated with changing the status quo with respect to the current state-of-the-art in biodiagnostic platforms and devices.
确定性定位的无机半导体纳米棒（NRs）和纳米管（NTs）合成简单，兼具化学稳定性、高表面积、可控光学性质和可调表面功能，这激发了全球范围内针对生物诊断应用的研究努力。基于定向排列的一维（1-D）无机半导体纳米结构的生物传感器已展现出卓越的检测灵敏度、高通量和无标记可操作性。与纳米颗粒悬浮液及离散随机取向的纳米线相比，纳米线（NW）和纳米管阵列提供了连续的电荷传输途径，这对于全电检测及利用电动效应而言是一个主要优势。我们综述了基于定向排列的NTs/NRs/NWs并采用传统检测方法的高灵敏度生物传感器，包括荧光、电化学和机电传感，以及纳米线特有的检测方法，如场效应晶体管。诸如刺入活细胞以原位监测细胞事件，以及具有电控润湿性以用于表面辅助激光解吸和电离的基底等全新类型的传感应用正在兴起，以利用纳米线阵列的独特性质。同时，我们解释了所采用的半导体材料和结构，以及用于构建生物传感器的功能化程序。基于排列半导体阵列的方法与主流技术相比受到了严格审视，以了解纳米管/纳米棒阵列生物传感器所占据的独特细分领域。纳米线/纳米管阵列所兼容的检测原理的多功能性使得能够采用混合方法，即使用多种检测方法的组合。这些优势抵消了在生物诊断平台和设备方面改变当前技术现状所带来的复杂性。
