Bollella Paolo, Fusco Giovanni, Tortolini Cristina, Sanzò Gabriella, Antiochia Riccarda, Favero Gabriele, Mazzei Franco
Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.
Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.
Anal Bioanal Chem. 2016 May;408(12):3203-11. doi: 10.1007/s00216-016-9389-z. Epub 2016 Feb 13.
In this work, several theoretical aspects involved in the first-generation inhibition-based electrochemical biosensor measurements have been discussed. In particular, we have developed a theoretical-methodological approach for the characterization of the kinetic interaction between alkaline phosphatase (AlP) and 2,4-dichlorophenoxy acetic acid (2,4-D) as representative inhibitor studied by means of cyclic voltammetry and amperometry. Based on these findings, a biosensor for the fast, simple, and inexpensive determination of 2,4-D has been developed. The enzyme has been immobilized on screen-printed electrodes (SPEs). To optimize the biosensor performances, several carbon-based SPEs, namely graphite (G), graphene (GP), and multiwalled carbon nanotubes (MWCNTs), have been evaluated. AlP was immobilized on the electrode surface by means of polyvinyl alcohol with styryl-pyridinium groups (PVA-SbQ) as cross-linking agent. In the presence of ascorbate 2-phosphate (A2P) as substrate, the herbicide has been determined, thanks to its inhibition activity towards the enzyme catalyzing the oxidation of A2P to ascorbic acid (AA). Under optimum experimental conditions, the best performance in terms of catalytic efficiency has been demonstrated by MWCNTs SPE-based biosensor. The inhibition biosensor shows a linearity range towards 2,4-D within 2.1-110 ppb, a LOD of 1 ppb, and acceptable repeatability and stability. This analysis method was applied to fortified lake water samples with recoveries above 90%. The low cost of this device and its good analytical performances suggest its application for the screening and monitoring of 2,4-D in real matrices.
在这项工作中，我们讨论了第一代基于抑制作用的电化学生物传感器测量中涉及的几个理论方面。特别是，我们开发了一种理论方法，用于表征碱性磷酸酶（AlP）与2,4-二氯苯氧基乙酸（2,4-D）之间的动力学相互作用，其中2,4-D作为代表性抑制剂，通过循环伏安法和安培法进行研究。基于这些发现，我们开发了一种用于快速、简单且低成本测定2,4-D的生物传感器。该酶已固定在丝网印刷电极（SPEs）上。为了优化生物传感器的性能，我们评估了几种碳基SPEs，即石墨（G）、石墨烯（GP）和多壁碳纳米管（MWCNTs）。通过以带有苯乙烯基吡啶鎓基团的聚乙烯醇（PVA-SbQ）作为交联剂，将AlP固定在电极表面。在以抗坏血酸2-磷酸酯（A2P）作为底物的情况下，由于除草剂对催化A2P氧化为抗坏血酸（AA）的酶具有抑制活性，因此可以对其进行测定。在最佳实验条件下，基于MWCNTs SPE的生物传感器在催化效率方面表现出最佳性能。该抑制型生物传感器对2,4-D的线性范围为2.1 - 110 ppb，检测限为1 ppb，并且具有可接受的重复性和稳定性。该分析方法应用于加标湖水样品，回收率高于90%。该设备成本低且分析性能良好，表明其可用于实际样品中2,4-D的筛选和监测。
