Carbon disulfide mediated self-assembly of Laccase and iron oxide nanoparticles on gold surfaces for biosensing applications

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• 作者：I. Almeida ; F. Henriques ; M.D. Carvalho ; A.S. Viana ; ^{anaviana@fc.ul.pt" class="auth_mail" title="E-mail the corresponding author}
• 关键词：In situ dithiocarbamate formation ; Biomolecule immobilization ; Magnetic nanoparticles ; Enzyme-modified electrodes ; Electrochemical biosensor
• 刊名：Journal of Colloid and Interface Science
• 出版年：2017
• 出版时间：1 January 2017
• 年：2017
• 卷：485
• 期：Complete
• 页码：242-250
• 全文大小：1633 K

文摘

A simple one-step methodology was explored to prepare enzyme-modified nanostructured electrodes for the development of biosensing interfaces. Magnetite type nanoparticles conjugated with Laccase were immobilized on gold surfaces. This approach relies on the reaction between carbon disulfide and amine groups of biomolecules to form dithiocarbamate (DTC) moieties, as well as on the strong affinity between sulfur species and metals. Special emphasis was given to demonstrate DTC formation in aqueous solution and further attachment to iron oxide nanoparticles and to gold electrodes. UV–visible spectroscopy confirmed the functionalization of nanoparticles by DTC using a model secondary amine (N-hexylmethylamine). The direct attachment of modified iron oxide nanoparticles (with ca. 20 or 40 nm mean sizes) to gold electrodes was investigated using the hormone epinephrine, with well-known electrochemical properties. A high amount of immobilized epinephrine and a facilitated redox conversion was observed for modified electrodes containing iron oxide nanoparticles. The success of this simple and robust method was confirmed by X-ray photoelectronic spectroscopy. Finally, the catalytic activity of modified gold with iron oxide nanoparticles and Laccase was evaluated toward 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS). Chronoamperometric studies revealed a significant catalytic activity of immobilized Laccase in the presence of the nanoparticles, in particular for the largest ones (40 nm), with a sensitivity for ABTS oxidation of 100 mA M⁻¹ cm⁻².