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Covalently electrografted carboxyphenyl layers onto gold surface serving as a platform for the construction of an immunosensor for detection of methotrexate
Umeå University, Faculty of Science and Technology, Department of Chemistry.
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2018 (English)In: Journal of Electroanalytical Chemistry, ISSN 1572-6657, Vol. 812, p. 235-243Article in journal (Refereed) Published
Abstract [en]

Abstract The classical way to modify a gold electrode surface for immunosensor development is through self-assembly of functionalised thiols for subsequent attachment of antibodies. Here is described a new pathway for surface modification using a diazonium salt-based immunosensor for detection of methotrexate (MTX) with electrochemical immittance spectroscopy (EIS). The diazonium salt, 4-carboxybenzenediazonium tetrafluoroborate was synthesized using a diazotization reaction and characterized by IR and cyclic voltammetry (CV). The Au electrode was electrografted with diazonium and used for anti-MTX antibody immobilization. The EIS detection of MTX was studied with and without application of redox probe; Fe(CN)63−/4−. MTX could not be detected using Fe(CN)63−/4−as redox probe, whereas EIS measurements without redox probe and analysis of the data with singular decomposition (SVD) gave good results. A multivariate calibration model showed good linear behavior on a logarithmic scale with a detection limit for MTX of 7×10−12molL−1.

Place, publisher, year, edition, pages
Elsevier, 2018. Vol. 812, p. 235-243
Keywords [en]
4-carboxybenzenediazonium tetrafluoroborate, Gold electrode, Antibody, Immunosensor, Singular value decomposition, Cyclic voltammetry, Chronoamperometry, Electrochemical impedance spectroscopy
National Category
Chemical Sciences
Identifiers
URN: urn:nbn:se:umu:diva-143882DOI: 10.1016/j.jelechem.2017.12.072ISI: 000445054900014OAI: oai:DiVA.org:umu-143882DiVA, id: diva2:1173462
Funder
Sida - Swedish International Development Cooperation AgencyAvailable from: 2018-01-12 Created: 2018-01-12 Last updated: 2019-11-07Bibliographically approved
In thesis
1. Development of electrochemical sensor and biosensor platforms: detection of therapeutic drugs and heavy metal ions
Open this publication in new window or tab >>Development of electrochemical sensor and biosensor platforms: detection of therapeutic drugs and heavy metal ions
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Electrochemical sensors and biosensors combine the sensitivity of electroanalytical methods with the selectivity of a sensor or biosensor surface. The chemical or biochemical component (receptor) in the sensor recognizes an analyte and produces an electrical signal which is proportional to the analyte concentration. Some of these sensors are routinely used in clinical applications and are known for their simplicity, portability, cost-effective, and miniaturization. The glucose sensor used in the management of diabetes is a good example of such biosensors.

This thesis deals with the development of electrochemical biosensor and sensor platforms for the detection of therapeutic drugs, demonstrated using methotrexate (MTX) which is the most common drug used for the treatment of cancer patients, and heavy metal ions (Pb2+ and Cd2+).

The biosensor surfaces were generated by immobilization of antibody (anti-MTX) on chemically modified gold electrodes using different surface modification protocols. Self-assemble monolayer (SAM) using alkanethiol (cysteamine) or electrografting with diazonium salt (4- carboxybenzenediaonium tetrafluoroborate, 4-CBD) was used for surface modification. The surface modification was monitored and characterized using electrochemical immittance spectroscopy (EIS) and cyclic voltammetry (CV) along with other complementary technique such as X-ray photoelectron spectroscopy (XPS). The biosensing surfaces were used for the detection of MTX in an electrochemical flow cell (paper I) and in a batch system (paper II). The detection was based on non-faradaic electrochemical immittance spectroscopy (EIS) and singular value decomposition (SVD) for data evaluation. Both electrochemical biosensors provided the lowest limit of detection, LOD (at picomolar level) compared to earlier reports.

The electrografting of 4-CBD on glassy carbon electrode (GCE) using CV and the parameters that influence the number of monolayers that can be grafted on the surface are demonstrated (paper III). The CVs obtained during grafting showed one or two reduction peaks, and this was found to be related to the number of monolayers deposited on the electrode. One can increase the number of monolayers by increasing the concentration of 4-CBD or decreasing the scan rate. The GCE, grafted using 4-CBD, was incorporated with Bi by an in situ electrodeposition of Bi3+ and used as an electrochemical sensor for detection of Pb2+ and Cd2+ using square wave anodic stripping voltammetry, SWASV (paper IV). The sensor resulted in LOD of 10 μg L-1 for Pb2+ and 25 μg L-1 for Cd2+. The applicability of the sensor was tested for detection of Pb2+ and Cd2+ in tap water and compared with ICP-OES. The results were comparable, demonstrating the potential of the sensor as an alternative to ICP-OES for the detection of metal ions in water samples.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2019. p. 64
Keywords
Sensors, electrode surface modification, electrochemical immitance spectroscopy, square wave anodic stripping voltammetry, singular value decomposition, therapeutic drugs, heavy metals
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-165049 (URN)978-91-7855-149-1 (ISBN)
Public defence
2019-12-13, KB.E3.01 (Lilla hörsalen), KBC-huset, Umeå, 10:00 (English)
Opponent
Supervisors
Available from: 2019-11-11 Created: 2019-11-07 Last updated: 2019-11-08Bibliographically approved

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Publisher's full texthttp://www.sciencedirect.com/science/article/pii/S1572665717309530

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Phal, SereilakhenaShatri, BesartLindholm-Sethson, BrittaTesfalidet, Solomon

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