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Kékedy-Nagy L, Perry JM, Little SR, Llorens OY, Shih SCC. An electrochemical aptasensor for Δ 9-tetrahydrocannabinol detection in saliva on a microfluidic platform. Biosens Bioelectron 2023; 222:114998. [PMID: 36549107 DOI: 10.1016/j.bios.2022.114998] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/21/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
We present a novel "on-off", cost-effective, rapid electrochemical aptasensor combined with a microfluidics cartridge system for the detection of Δ9-THC (Δ9-tetrahydrocannabinol) in human saliva via differential pulse voltammetry. The assay relied on the competitive binding between the Δ9-THC and a soluble redox indicator methylene blue, using an aptamer selected via FRELEX. We found that the aptasensor can detected 1 nM of Δ9-THC in PBS in a three-electrode cell system, while the sensitivity and both the dissociation constant (Kd) and association constant (Kb) were dependent on the aptamer density. The aptamer also showed great affinity towards Δ9-THC when tested against cannabinol and cannabidiol. The same limit of detection of 1 nM in PBS was achieved in small volume samples (∼60 μL) using the aptamer-modified gold screen-printed electrodes combined with the microfluidic cartridge setup, however, the presence of 10% raw human saliva had a negative effect which manifested in a 10-fold increase in the LOD due to interfering elements. Filtering the saliva, improved the tested volume to 50% and the LOD to 5 nM of Δ9-THC which is lower than the concentrations associated with impairment (6.5-32 nM). The aptasensor showed a good storage capability up to 3 days, however, the reusability significantly dropped from 10 cycles (freshly prepared) to 5 cycles. The results clearly demonstrate the feasibility of the aptasensor platform with the microfluidics chamber towards a point-of-care testing application for the detection of Δ9-THC in saliva.
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Affiliation(s)
- László Kékedy-Nagy
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd West, Montreal, Quebec, H3G1M8, Canada; Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B1R6, Canada
| | - James M Perry
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B1R6, Canada; Department of Biology, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B1R6, Canada
| | - Samuel R Little
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd West, Montreal, Quebec, H3G1M8, Canada; Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B1R6, Canada
| | - Oriol Y Llorens
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd West, Montreal, Quebec, H3G1M8, Canada; Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B1R6, Canada
| | - Steve C C Shih
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd West, Montreal, Quebec, H3G1M8, Canada; Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B1R6, Canada; Department of Biology, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B1R6, Canada.
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Sosna M, Ferapontova EE. Electron Transfer in Binary Hemin-Modified Alkanethiol Self-Assembled Monolayers on Gold: Hemin's Lateral and Interfacial Interactions. Langmuir 2022; 38:11180-11190. [PMID: 36062334 DOI: 10.1021/acs.langmuir.2c01064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Orientated coupling of redox enzymes to electrodes by their reconstitution onto redox cofactors, such as hemin conjugated to self-assembled monolayers (SAMs) formed on the electrodes, poses the requirements for a SAM design enabling reconstitution. We show that the kinetics of electron transfer (ET) in binary SAMs of alkanethiols on gold composed of in situ hemin-conjugated 11-amino-1-undecanethiol (AUT) and diluting OH-terminated alkanethiols with 11, 6, and 2 methylene groups (MC11OH, MC6OH, and MC2OH) depends on both the SAM composition and surface density of hemin, Γheme. In AUT/MC11OH SAMs composed of equal linker/diluent lengths, the heterogeneous ET rate constant ks decreased with the Γheme and varied between 70 and 500 s-1. For shorter diluents, the ks of 245-330 s-1 (C6) and 300-340 s-1 (C2) showed a little (if any) Γheme dependence. In AUT/MC11OH SAMs, the increasing Γheme resulted in the steric crowding of hemin species and their neighboring lateral interactions in the plane of hemin localization, affecting the potential distribution at the SAM/electrode interface and inducing local electrostatic effects interfering with hemin oxidation. In AUT/MC6OH and AUT/MC2OH SAMs, hemin discharged at the plane of the closest approach to the gold surface, equal to the diluent length and permeable to electrolyte ions, which lessened those effects. All studied binary SAMs provided steric hindrance for protein reconstitution on the hemin cofactor conjugated to the extended AUT linker. Further use of SAM-modified electrodes with the covalently attached hemin as interfaces for heme proteins' reconstitution should consider SAMs with loosely dispersed redox centers terminating more rigid molecular wires. Such wires place hemin at fixed distances from the electrode surface and thus ensure the interfacial properties required for the effective on-surface reconstitution of proteins and enzymes.
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Affiliation(s)
- Maciej Sosna
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Elena E Ferapontova
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
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Salimian R, Kékedy-Nagy L, Ferapontova EE. Specific Picomolar Detection of a Breast Cancer Biomarker HER-2/neu
Protein in Serum: Electrocatalytically Amplified Electroanalysis by the Aptamer/PEG-Modified Electrode. ChemElectroChem 2017. [DOI: 10.1002/celc.201700025] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Razieh Salimian
- Interdisciplinary Nanoscience Center (iNANO), Faculty of Science and Technology; Aarhus University; Gustav Wieds Vej 14 8000 Aarhus C Denmark
- Center for DNA Nanotechnology (CDNA) at iNANO
- Sharif University of Technology; Teheran Iran
| | - László Kékedy-Nagy
- Interdisciplinary Nanoscience Center (iNANO), Faculty of Science and Technology; Aarhus University; Gustav Wieds Vej 14 8000 Aarhus C Denmark
- Center for DNA Nanotechnology (CDNA) at iNANO
| | - Elena E. Ferapontova
- Interdisciplinary Nanoscience Center (iNANO), Faculty of Science and Technology; Aarhus University; Gustav Wieds Vej 14 8000 Aarhus C Denmark
- Center for DNA Nanotechnology (CDNA) at iNANO
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