Condensed Matter Science and Technology Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin 150080, China.
Nanoscale. 2019 Aug 1;11(30):14322-14329. doi: 10.1039/c9nr02330e.
Development of fluorescence enhancement (FE) platforms based on ZnO nanorods (NRs) has sparked considerable interest, thanks to their well-demonstrated potential in chemical and biological detection. Among the multiple factors determining the FE performance, high-order waveguide modes are specifically promising in boosting the sensitivity and realizing selective detection. However, quantitative experimental studies on the influence of the NR diameter, substrate, and surrounding medium, on the waveguide-based FE properties remain lacking. In this work, we have designed and fabricated a FE platform based on patterned and well-defined arrays of vertical, hexagonal prism ZnO NRs with six distinct diameters. Both direct experimental evidence and theoretical simulations demonstrate that high-order waveguide modes play a crucial role in FE, and are strongly dependent on the NR diameter, substrate, and surrounding medium. Using the optimized FE platform, a significant limit of detection (LOD) of 10-16 mol L-1 for Rhodamine-6G probe detection is achieved. Especially, a LOD as low as 10-14 g mL-1 is demonstrated for a prototype biomarker of carcinoembryonic antigen, which is improved by one order compared with the best LOD ever reported using fluorescence-based detection. This work provides an efficient path to design waveguiding NRs-based biochips for ultrasensitive and highly-selective biosensing.
基于氧化锌纳米棒（NRs）的荧光增强（FE）平台的发展引起了极大的兴趣，因为它们在化学和生物检测方面具有很好的应用潜力。在决定 FE 性能的多个因素中，高阶波导模式在提高灵敏度和实现选择性检测方面具有特别的优势。然而，关于 NR 直径、衬底和周围介质对基于波导的 FE 特性的影响的定量实验研究仍然缺乏。在这项工作中，我们设计并制造了一种基于图案化和定义良好的垂直六方棱柱 ZnO NR 阵列的 FE 平台，这些 NR 具有六个不同的直径。直接实验证据和理论模拟都表明，高阶波导模式在 FE 中起着至关重要的作用，并且强烈依赖于 NR 直径、衬底和周围介质。使用优化后的 FE 平台，实现了对 Rhodamine-6G 探针检测的 10-16 mol L-1 的显著检测限（LOD）。特别是，对于癌胚抗原的原型生物标志物，实现了低至 10-14 g mL-1 的 LOD，与使用荧光检测报告的最佳 LOD 相比提高了一个数量级。这项工作为设计基于导波 NR 的生物芯片提供了一条有效的途径，用于超灵敏和高选择性的生物传感。
