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Bilibana MP, Williams AR, Rassie C, Sunday CE, Makelane H, Wilson L, Ntshongontshi N, Jijana AN, Masikini M, Baker PGL, Iwuoha EI. Electrochemical Aptatoxisensor Responses on Nanocomposites Containing Electro-Deposited Silver Nanoparticles on Poly(Propyleneimine) Dendrimer for the Detection of Microcystin-LR in Freshwater. Sensors (Basel) 2016; 16:E1901. [PMID: 27845719 PMCID: PMC5134560 DOI: 10.3390/s16111901] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 02/07/2023]
Abstract
A sensitive and reagentless electrochemical aptatoxisensor was developed on cobalt (II) salicylaldiimine metallodendrimer (SDD-Co(II)) doped with electro-synthesized silver nanoparticles (AgNPs) for microcystin-LR (L, l-leucine; R, l-arginine), or MC-LR, detection in the nanomolar range. The GCE|SDD-Co(II)|AgNPs aptatoxisensor was fabricated with 5' thiolated aptamer through self-assembly on the modified surface of the glassy carbon electrode (GCE) and the electronic response was measured using cyclic voltammetry (CV). Specific binding of MC-LR with the aptamer on GCE|SDD-Co(II)|AgNPs aptatoxisensor caused the formation of a complex that resulted in steric hindrance and electrostatic repulsion culminating in variation of the corresponding peak current of the electrochemical probe. The aptatoxisensor showed a linear response for MC-LR between 0.1 and 1.1 µg·L-1 and the calculated limit of detection (LOD) was 0.04 µg·L-1. In the detection of MC-LR in water samples, the aptatoxisensor proved to be highly sensitive and stable, performed well in the presence of interfering analog and was comparable to the conventional analytical techniques. The results demonstrate that the constructed MC-LR aptatoxisensor is a suitable device for routine quantification of MC-LR in freshwater and environmental samples.
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Affiliation(s)
- Mawethu P Bilibana
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Avril R Williams
- Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill, St. Michael BB11000, Barbados.
| | - Candice Rassie
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Christopher E Sunday
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Hlamulo Makelane
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Lindsay Wilson
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Nomaphelo Ntshongontshi
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Abongile N Jijana
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Milua Masikini
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Priscilla G L Baker
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
| | - Emmanuel I Iwuoha
- SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa.
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Sunday CE, Masikini M, Wilson L, Rassie C, Waryo T, Baker PGL, Iwuoha EI. Application on gold nanoparticles-dotted 4-nitrophenylazo graphene in a label-free impedimetric deoxynivalenol immunosensor. Sensors (Basel) 2015; 15:3854-71. [PMID: 25668213 PMCID: PMC4367389 DOI: 10.3390/s150203854] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 11/17/2014] [Accepted: 12/07/2014] [Indexed: 01/01/2023]
Abstract
In this paper, we report a new concept to construct a label-free electrochemical inhibition-based immunosensor for the detection of the mycotoxin deoxynivalenol (DON) in cereal samples. The electrochemical impedance spectroscopy of tris(bipyridine) ruthenium (II) chloride was used as a marker enhanced with gold nanoparticles-dotted 4-nitrophenylazo functionalized graphene (AuNp/G/PhNO2) nanocatalyst mediated in Nafion on a glassy carbon electrode. Under the optimized conditions, the formation of immunocomplexes inhibited electron flow and increased the charge transfer resistance of the sensing interface linearly. The change in impedance was proportional to DON concentrations in the range of 6–30 ng/mL with a sensitivity and detection limit of 32.14 ΩL/ng and 0.3 μg/mL, respectively, which compares favorably with the ELISA result. The proposed sensor had a stability of 80.3%, good precision and selectivity in DON standard solution containing different interfering agents, indicating promising application prospect for this strategy in designing impedimetric, electrochemiluminescent, voltammetric or amperometric sensors.
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Affiliation(s)
- Christopher Edozie Sunday
- Sensor Laboratory, Chemistry Department, University of the Western Cape, Private Bag X 17, Bellville 7535, South Africa.
| | - Milua Masikini
- Sensor Laboratory, Chemistry Department, University of the Western Cape, Private Bag X 17, Bellville 7535, South Africa.
| | - Lindsay Wilson
- Sensor Laboratory, Chemistry Department, University of the Western Cape, Private Bag X 17, Bellville 7535, South Africa.
| | - Candice Rassie
- Sensor Laboratory, Chemistry Department, University of the Western Cape, Private Bag X 17, Bellville 7535, South Africa.
| | - Tesfaye Waryo
- Sensor Laboratory, Chemistry Department, University of the Western Cape, Private Bag X 17, Bellville 7535, South Africa.
| | - Pricilla G L Baker
- Sensor Laboratory, Chemistry Department, University of the Western Cape, Private Bag X 17, Bellville 7535, South Africa.
| | - Emmanuel I Iwuoha
- Sensor Laboratory, Chemistry Department, University of the Western Cape, Private Bag X 17, Bellville 7535, South Africa.
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Masikini M, Mailu SN, Tsegaye A, Njomo N, Molapo KM, Ikpo CO, Sunday CE, Rassie C, Wilson L, Baker PGL, Iwuoha EI. A fumonisins immunosensor based on polyanilino-carbon nanotubes doped with palladium telluride quantum dots. Sensors (Basel) 2014; 15:529-46. [PMID: 25558993 PMCID: PMC4327034 DOI: 10.3390/s150100529] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/22/2014] [Indexed: 11/16/2022]
Abstract
An impedimetric immunosensor for fumonisins was developed based on poly(2,5-dimethoxyaniline)-multi-wall carbon nanotubes doped with palladium telluride quantum dots onto a glassy carbon surface. The composite was assembled by a layer-by-layer method to form a multilayer film of quantum dots (QDs) and poly(2,5-dimethoxyaniline)-multi-wall carbon nanotubes (PDMA-MWCNT). Preparation of the electrochemical immunosensor for fumonisins involved drop-coating of fumonisins antibody onto the composite modified glassy carbon electrode. The electrochemical impedance spectroscopy response of the FB1 immunosensor (GCE/PT-PDMA-MWCNT/anti-Fms-BSA) gave a linear range of 7 to 49 ng L-1 and the corresponding sensitivity and detection limits were 0.0162 kΩ L ng-1 and 0.46 pg L-1, respectively, hence the limit of detection of the GCE/PT-PDMA-MWCNT immunosensor for fumonisins in corn certified material was calculated to be 0.014 and 0.011 ppm for FB1, and FB2 and FB3, respectively. These results are lower than those obtained by ELISA, a provisional maximum tolerable daily intake (PMTDI) for fumonisins (the sum of FB1, FB2, and FB3) established by the Joint FAO/WHO expert committee on food additives and contaminants of 2 μg kg-1 and the maximum level recommended by the U.S. Food and Drug Administration (FDA) for protection of human consumption (2-4 mg L-1).
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Affiliation(s)
- Milua Masikini
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Stephen N Mailu
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Abebaw Tsegaye
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Njagi Njomo
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Kerileng M Molapo
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Chinwe O Ikpo
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Christopher Edozie Sunday
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Candice Rassie
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Lindsay Wilson
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Priscilla G L Baker
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
| | - Emmanuel I Iwuoha
- SensorLab, Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Cape Town, South Africa.
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