Pyrenyl carbon nanostructures for ultrasensitive measurements of formaldehyde in urine.
Pyrenyl carbon nanostructures for ultrasensitive measurements of formaldehyde in urine.
复制标题
DOI：
10.1016/j.aca.2017.03.032
复制
发表时间：
2017-06-01
影响因子：
6.2
通讯作者：
Krishnan S
中科院分区：
文献类型：
--
作者：
Premaratne G;Farias S;Krishnan S
测量超低（例如，十亿分之几）体液中小分子标记物的水平（例如，血清、尿液、唾液）涉及到设计具有灵敏度和选择性的测定策略的相当大的挑战。本文中，我们首次报道了电流型纳米生物电极设计，其独特地将1-芘丁酸单元pi-pi与羧基化多壁碳纳米管堆叠在丝网印刷电极表面上，用于共价连接NAD+依赖性甲醛脱氢酶（FDH）。所设计的酶生物电极在10倍稀释的尿液中提供了6ppb的甲醛检测，具有10 ppb至10 ppm的宽动态范围。傅里叶变换红外光谱、拉曼光谱和电化学阻抗谱表征证实了FDH生物电极的成功设计。与搅拌溶液法（表观KM 19.9 ± 4.6 ppm）相比，流动注射分析提供了更低的检测限和更高的甲醛亲和力（表观KM 9.6 ± 1.2 ppm）。选择性分析表明，生物电极对甲醛具有选择性，对乙醛具有中等交叉反应性（约25%），对丙醛、丙酮、甲醇和乙醇的交叉反应性可忽略不计。甲醛是一种室内污染物，研究表明，长期和高剂量接触该化合物具有神经毒性特征和全身毒性作用。此外，报道的色谱和质谱方法确定了与健康人相比，膀胱癌、痴呆和早期认知障碍患者的尿甲醛水平升高。结果表明，基于芘基碳纳米结构的FDH生物电极设计代表了酶选择性电化学定量小30 Da甲醛的新奇和简单性。所提出的方法对于其他小分子标记物的更广泛的适用性是可行的，其仅需要设计适当的标记物特异性酶系统或受体分子。这是第一份基于芘基碳纳米结构的酶生物电极的报告，用于定量尿液中的甲醛标记物，代表了一种非侵入性的小分子测定方法。
Measurement of ultra-low (e.g., parts-per-billion) levels of small-molecule markers in body fluids (e.g., serum, urine, saliva) involves a considerable challenge in view of designing assay strategies with sensitivity and selectivity. Herein we report for the first time an amperometric nano-bioelectrode design that uniquely combines 1-pyrenebutyric acid units pi-pi stacked with carboxylated multiwalled carbon nanotubes on the surface of gold screen printed electrodes for covalent attachment of NAD+ dependent formaldehyde dehydrogenase (FDH). The designed enzyme bioelectrode offered 6 ppb formaldehyde detection in 10-times diluted urine with a wide dynamic range of 10 ppb to 10 ppm. Fourier transform infrared, Raman, and electrochemical impedance spectroscopic characterizations confirmed the successful design of the FDH bioelectrode. Flow injection analysis provided lower detection limit and greater affinity for formaldehyde (apparent KM 9.6 ± 1.2 ppm) when compared with stirred solution method (apparent KM 19.9 ± 4.6 ppm). Selectivity assays revealed that the bioelectrode was selective toward formaldehyde with a moderate cross-reactivity for acetaldehyde (~ 25%) and negligible cross-reactivity toward propanaldehyde, acetone, methanol, and ethanol. Formaldehyde is an indoor pollutant, and studies have indicated neurotoxic characteristics and systemic toxic effects of this compound upon chronic and high doses of exposure. Moreover, reported chromatography and mass spectrometry methods identified elevated urine formaldehyde levels in patients with bladder cancer, dementia, and early stages of cognitive impairments compared to healthy people. Results demonstrate that pyrenyl carbon nanostructures-based FDH bioelectrode design represents novelty and simplicity for enzyme-selective electrochemical quantitation of small 30 Da formaldehyde. Broader applicability of the presented approach for other small-molecule markers is feasible that requires only the design of appropriate marker-specific enzyme systems or receptor molecules. This is the first report of a pyrenyl carbon nanostructure based enzymatic bioelectrode for quantitation of formaldehyde marker in urine representing a non-invasive small-molecule assay methodology.