Naseri Amene, Ghasemi Forough
Department of Nanotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education, and Extension Organization (AREEO), Karaj, 3135933151, Iran.
Nanotechnology. 2021 Nov 24;33(7). doi: 10.1088/1361-6528/ac3704.
Visual detection based on gold nanorods (AuNRs) has gained tremendous attention in sensing applications owing to the potential for simple, inexpensive, instrument-free, and on-site detection. The proper selection of the mechanism involved in the interaction between the analyte and the nanostructure plays a significant role in designing a selective and multicolorimetric probe for visual purposes. A winning mechanism to develop multicolorimetric probes is the silver metalization of AuNRs. Herein, an unprecedented idea is presented to expand the variety of multicolorimetric sensors relying on the mechanism of silver deposition. We introduce the anti-silver deposition mechanism in which the analyte directly or indirectly restrains the silver coating of AuNRs. To ascertain the anti-silver deposition mechanism, we have exploited the proposed idea for the direct detection of nitrate. The presence of nitrate (as restrainer agent), which was firstly treated with ascorbic acid (as reducing agent), induced a decrease in the spectral blueshift of AuNRs along with diverse sharp color transitions from reddish-orange (blank) to maroon, wine, berry/purple, dark blue, teal, green, seafoam, and mint. The difference in the spectrum area of the probe in the absent () and presence () of nitrate were linearly proportional to nitrate concentration in the range of 0.5-5.5 mmol land the limit of detection was calculated to be 465mol l. Furthermore, the practicability of the multicolor probe was assessed by the determination of nitrate in complex environmental samples.
基于金纳米棒（AuNRs）的视觉检测因其具有简单、廉价、无需仪器且可现场检测的潜力，在传感应用中受到了极大关注。在设计用于视觉目的的选择性和多比色探针时，正确选择分析物与纳米结构之间相互作用所涉及的机制起着重要作用。开发多比色探针的一个成功机制是AuNRs的银金属化。在此，我们提出了一个前所未有的想法，以扩展基于银沉积机制的多比色传感器的种类。我们引入了抗银沉积机制，即分析物直接或间接抑制AuNRs的银涂层。为了确定抗银沉积机制，我们利用这一提出的想法直接检测硝酸盐。硝酸盐（作为抑制剂）首先用抗坏血酸（作为还原剂）处理，其存在导致AuNRs光谱蓝移减小，同时伴随着从红橙色（空白）到栗色、酒红色、浆果/紫色、深蓝色、蓝绿色、绿色、海泡色和薄荷色等多种鲜明的颜色转变。在不存在（）和存在（）硝酸盐的情况下，探针光谱面积的差异与0.5 - 5.5 mmol范围内的硝酸盐浓度呈线性比例关系，计算得出检测限为465μmol/L。此外，通过测定复杂环境样品中的硝酸盐来评估多色探针的实用性。
