Carbon disulfide mediated self-assembly of Laccase and iron oxide nanoparticles on gold surfaces for biosensing applications.
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 40nm 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 (40nm), with a sensitivity for ABTS oxidation of 100mAM-1cm-2.
Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Edifício C8, Campo Grande, 1749-016 Lisboa, Portugal.
I
I
Almeida
Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Edifício C8, Campo Grande, 1749-016 Lisboa, Portugal.
F
F
Henriques
Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Edifício C8, Campo Grande, 1749-016 Lisboa, Portugal.
M D
MD
Carvalho
Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Edifício C8, Campo Grande, 1749-016 Lisboa, Portugal. Electronic address: anaviana@fc.ul.pt.
A S
AS
Viana
D052160:Benzothiazoles / Q000032:analysis; D015374:Biosensing Techniques; D002246:Carbon Disulfide / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004837:Epinephrine / Q000032:analysis; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D042845:Laccase / Q000737:chemistry*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D012996:Solutions; D013451:Sulfonic Acids / Q000032:analysis; D013859:Thiocarbamates; D014867:Water
D052160:Benzothiazoles; D004800:Enzymes, Immobilized; D058185:Magnetite Nanoparticles; D012996:Solutions; D013451:Sulfonic Acids; D013859:Thiocarbamates; D014867:Water; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D006046:Gold; D042845:Laccase; D002246:Carbon Disulfide; D052203:Ferrosoferric Oxide; D004837:Epinephrine
Biomolecule immobilization; Electrochemical biosensor; Enzyme-modified electrodes; In situ dithiocarbamate formation; Magnetic nanoparticles