Controlled side-by-side assembly of gold nanorods: A strategy for lead detection

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• 作者：Huai-Hong Cai ^{thhcai@jnu.edu.cn" class="auth_mail}Author Vitae ; Dewen LinAuthor Vitae ; Jinhui WangAuthor Vitae ; Pei-Hui Yang ; ^{typh@jnu.edu.cn" class="auth_mail}Author Vitae ; Jiye CaiAuthor Vitae
• 关键词：Assembly ; Functionalization ; Gold nanorods ; Lead ions ; Sensing
• 刊名：Sensors and Actuators B: Chemical
• 出版年：June, 2014
• 年：2014
• 卷：196
• 期：Complete
• 页码：252-259
• 全文大小：2031 K

文摘

A label-free and aggregation-based gold nanorods (AuNRs) probe has been developed for the detection of Pb²⁺ in aqueous solution, based on the fact that Pb²⁺ ions induce assembly mediated signal enhancement of cysteine-functionalized AuNRs. Cysteine (Cys) molecules are conjugated on AuNR surfaces to form cysteine-modified AuNRs (Cys-AuNRs), acting as nanoprobes in the detection of Pb²⁺. Transmission electron microscopy (TEM) and UV-vis absorption spectroscopy data reveal the formation of controlled side-by-side assembly of the AuNRs in the presence of Pb²⁺. The formation of aggregation of AuNRs significantly enhances detection signals, leading to dramatic decrease in the longitudinal surface plasmon resonance (SPR) absorption. The experiment conditions, including AuNRs aspect ratio, reaction time, pH value and salt concentration, are optimized. The Cys-AuNRs probe is highly sensitive (LOD = 0.1 nM) and selective toward Pb²⁺ ions, with a liner detection range from 0.1 nM to 1.0 nM. This system only becomes less sensitive when other metal ion is present at a very high concentration (i.e., >0.5 渭M). The cost-effective nanoprobes allow rapid and simple determination of the concentration of Pb²⁺ ions in city tap water samples, with results showing its practicality for the detection of lead in real samples.