Department of Chemistry, University of California , Riverside, 92521 California, United States.
Department of Chemistry, Institute of Biomedical Sciences and State Key Lab of Molecular Engineering of Polymers, Shanghai Stomatological Hospital, Fudan University , Shanghai 200433, China.
Anal Chem. 2017 Nov 7;89(21):11758-11764. doi: 10.1021/acs.analchem.7b03336. Epub 2017 Oct 27.
Nanomaterials have shown great promise in advancing biomedical and environmental analysis because of the unique properties originated from their ultrafine dimensions. In general, nanomaterials are separately applied to either enhance detection by producing strong signals upon target recognition or to specifically extract analytes taking advantage of their high specific surface area. Herein, we report a dual-functional nanomaterial-based platform that can simultaneously enrich and enable sensitive detection of multiple metal ions. The macroporous graphene foam (GF) we prepared displays abundant phosphate groups on the surface and can extract divalent metal ions via metal-phosphate coordination. The enriched metal ions then activate the metal-responsive DNAzymes and produce the fluorescently labeled single-stranded DNAs that are adsorbed and quenched by the GF. The resultant fluorescence reduction can be used for metal quantitation. The present work demonstrated duplexed detection of Pb and Cu using the Pb- and Cu-responsive DNAzymes, achieving a low detection limit of 50 pM and 0.6 nM, respectively. Successful quantification of Pb and Cu in human serum and river water were achieved with high metal recovery. Since the phosphate-decorated GF can enrich diverse types of divalent metal cations, this dual-functional GF-DNAzyme platform can serve as a simple and cost-effective tool for rapid and accurate metal quantification in determination of human metal exposure and inspection of environmental contamination.
纳米材料由于其超细微尺寸而具有独特的性质，在推进生物医学和环境分析方面显示出巨大的应用前景。通常，纳米材料分别应用于通过在目标识别时产生强信号来增强检测，或利用其高比表面积来专门提取分析物。在这里，我们报告了一种基于双功能纳米材料的平台，该平台可以同时富集并实现对多种金属离子的灵敏检测。我们制备的大孔石墨烯泡沫（GF）表面具有丰富的磷酸基团，可以通过金属-磷酸配位提取二价金属离子。富集的金属离子随后激活金属响应性 DNA 酶，并产生被 GF 吸附和猝灭的荧光标记单链 DNA。所得荧光减少可用于金属定量。本工作使用 Pb 和 Cu 响应性 DNA 酶对 Pb 和 Cu 进行了双重检测，分别实现了 50 pM 和 0.6 nM 的低检测限。通过高金属回收率成功定量了人血清和河水中的 Pb 和 Cu。由于磷酸修饰的 GF 可以富集多种类型的二价金属阳离子，因此这种双功能 GF-DNA 酶平台可以作为一种简单且具有成本效益的工具，用于快速准确地定量测定人体金属暴露和检测环境污染中的金属。
