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Uhuo O, Waryo T, Oranzie M, Sanga N, Leve Z, January J, Tshobeni Z, Pokpas K, Douman S, Iwuoha E. Interferon gamma (IFN-γ)-sensitive TB aptasensor based on novel chitosan-indium nano-kesterite (χtCITS)-labeled DNA aptamer hairpin technology. Bioelectrochemistry 2024; 158:108693. [PMID: 38554559 DOI: 10.1016/j.bioelechem.2024.108693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 03/15/2024] [Accepted: 03/16/2024] [Indexed: 04/01/2024]
Abstract
There has been increasing interest in the use of biosensors for diagnosis of infectious diseases such as tuberculosis (TB) due to their simplicity, affordability, and potential for point-of-care application. The incorporation of aptamer molecules and nanomaterials in biosensor fabrication explores the advantages of high-binding affinity and low immunogenicity of aptamers as well as the high surface-to-volume ratio of nanomaterials, for increased aptasensor performance. In this work, we employed a novel microwave-synthesized copper indium tin sulfide (CITS) substituted-kesterite nanomaterial, together with a natural biopolymer (chitosan), for signal amplification and increased loading of aptamer molecules. Study of the optical properties of CITS nanomaterials showed strong absorption in the UV region characteristic of kesterite semiconductor nanomaterials. X-ray diffraction analysis confirmed the presence of the kesterite phase with average crystallite size of 6.188 nm. Fabrication of interferon-gamma (IFN-γ) TB aptasensor with a chitosan-CITS nanocomposite (χtCITS) increased the aptasensor's electrochemical properties by 77.5 % and improved aptamer loading by 73.7 %. The aptasensor showed excellent sensitivity to IFN-γ concentrations with limit of detection of 6885 fg/mL (405 fM) and linear range of 850-17000 fg/mL (50 - 1000 fM). The aptasensor also exhibited excellent storage and electrochemical stability, with good selectivity towards IFN-γ and possible real sample application.
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Affiliation(s)
- Onyinyechi Uhuo
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa.
| | - Tesfaye Waryo
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa
| | - Marlon Oranzie
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa
| | - Nelia Sanga
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa
| | - Zandile Leve
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa
| | - Jaymi January
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa
| | - Ziyanda Tshobeni
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa
| | - Keagan Pokpas
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa
| | - Samantha Douman
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa; Department of Chemistry, PD Hahn Building, 28 Chemistry Road, Upper Campus, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa
| | - Emmanuel Iwuoha
- SensorLab (University of the Western Cape Sensor Laboratories), Chemical Sciences Building, University of the Western Cape, Bellville 7535, Cape Town, South Africa.
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Robinson C, Juska VB, O'Riordan A. Surface chemistry applications and development of immunosensors using electrochemical impedance spectroscopy: A comprehensive review. ENVIRONMENTAL RESEARCH 2023; 237:116877. [PMID: 37579966 DOI: 10.1016/j.envres.2023.116877] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/04/2023] [Accepted: 08/10/2023] [Indexed: 08/16/2023]
Abstract
Immunosensors are promising alternatives as detection platforms for the current gold standards methods. Electrochemical immunosensors have already proven their capability for the sensitive, selective, detection of target biomarkers specific to COVID-19, varying cancers or Alzheimer's disease, etc. Among the electrochemical techniques, electrochemical impedance spectroscopy (EIS) is a highly sensitive technique which examines the impedance of an electrochemical cell over a range of frequencies. There are several important critical requirements for the construction of successful impedimetric immunosensor. The applied surface chemistry and immobilisation protocol have impact on the electroanalytical performance of the developed immunosensors. In this Review, we summarise the building blocks of immunosensors based on EIS, including self-assembly monolayers, nanomaterials, polymers, immobilisation protocols and antibody orientation.
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Affiliation(s)
- Caoimhe Robinson
- Tyndall National Institute, University College Cork, T12 R5CP, Cork, Ireland
| | - Vuslat B Juska
- Tyndall National Institute, University College Cork, T12 R5CP, Cork, Ireland.
| | - Alan O'Riordan
- Tyndall National Institute, University College Cork, T12 R5CP, Cork, Ireland.
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Jaćević V, Dumanović J, Alomar SY, Resanović R, Milovanović Z, Nepovimova E, Wu Q, Franca TCC, Wu W, Kuča K. Research update on aflatoxins toxicity, metabolism, distribution, and detection: A concise overview. Toxicology 2023; 492:153549. [PMID: 37209941 DOI: 10.1016/j.tox.2023.153549] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/07/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023]
Abstract
Serious health risks associated with the consumption of food products contaminated with aflatoxins (AFs) are worldwide recognized and depend predominantly on consumed AF concentration by diet. A low concentration of aflatoxins in cereals and related food commodities is unavoidable, especially in subtropic and tropic regions. Accordingly, risk assessment guidelines established by regulatory bodies in different countries help in the prevention of aflatoxin intoxication and the protection of public health. By assessing the maximal levels of aflatoxins in food products which are a potential risk to human health, it's possible to establish appropriate risk management strategies. Regarding, a few factors are crucial for making a rational risk management decision, such as toxicological profile, adequate information concerning the exposure duration, availability of routine and some novel analytical techniques, socioeconomic factors, food intake patterns, and maximal allowed levels of each aflatoxin in different food products which may be varied between countries.
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Affiliation(s)
- Vesna Jaćević
- Department for Experimental Pharmacology and Toxicology, National Poison Control Centre, Military Medical Academy, Crnotravska 17, 11000 Belgrade, Serbia; Medical Faculty of the Military Medical Academy, University of Defence, Crnotravska 17, 11000 Belgrade, Serbia; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic.
| | - Jelena Dumanović
- Medical Faculty of the Military Medical Academy, University of Defence, Crnotravska 17, 11000 Belgrade, Serbia; Department of Analytical Chemistry, Faculty of Chemistry, University of Belgrade, 11158 Belgrade, Serbia
| | - Suliman Y Alomar
- King Saud University, College of Science, Zoology Department, Riyadh, 11451, Saudi Arabia
| | - Radmila Resanović
- Faculty of Veterinary Medicine, University of Belgrade, Bulevar Oslobođenja 18, 11000 Belgrade, Serbia
| | - Zoran Milovanović
- Special Police Unit, Ministry of Interior, Trebevićka 12/A, 11 030 Belgrade, Serbia
| | - Eugenie Nepovimova
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Qinghua Wu
- College of Life Science, Yangtze University, 1 Nanhuan Road, 434023 Jingzhou, Hubei, China; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Tanos Celmar Costa Franca
- Laboratory of Molecular Modeling Applied to the Chemical and Biological Defense, Military Institute of Engineering, Praça General Tibúrcio 80, Rio de Janeiro, RJ 22290-270, Brazil; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Wenda Wu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China; MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Kamil Kuča
- Biomedical Research Center, University Hospital Hradec Kralove, 50005, Hradec Kralove, Czech Republic; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
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Chokkareddy R, Redhi GG. Fe
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Nanorods‐RGO‐ionic Liquid Nanocomposite Based Electrochemical Sensor for Aflatoxin B1 in Ground Paprika. ELECTROANAL 2021. [DOI: 10.1002/elan.202100377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Rajasekhar Chokkareddy
- Department of Chemistry Durban University of Technology Durban South Africa- 4001
- Department of Chemistry Aditya College of Engineering and Technology Surampalem 533437 Andhra Pradesh India
| | - Gan G. Redhi
- Department of Chemistry Durban University of Technology Durban South Africa- 4001
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An Impedance Based Electrochemical Immunosensor for Aflatoxin B1 Monitoring in Pistachio Matrices. CHEMOSENSORS 2020. [DOI: 10.3390/chemosensors8040121] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Aflatoxins are highly toxic fungal secondary metabolites that often contaminate food and feed commodities. An electrochemical immunosensor for the determination of aflatoxin B1 (AFB1) was fabricated by immobilizing monoclonal AFB1 antibodies onto a screen-printed gold electrode that was modified with carbo-methyldextran by N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide cross-linking. An electrochemical interfacial modelling of biomolecular recognition was suggested and reasonably interpreted. Impedance technology was employed for the quantitative determination of AFB1. The limit of detection concentration of AFB1 for standard solutions and spiked pistachio samples was 0.5 ng/mL and 1 ng/mL, respectively. The immunosensor was able to successfully determine AFB1 concentrations in the range of 4.56–50.86 ng/mL in unknown pistachio samples. Comparative chromatographic analysis revealed that AFB1 concentrations that were higher than 345 ng/mL were not within the immunosensor’s upper limits of detection. Selectivity studies against Ochratoxin A and Aflatoxin M1 demonstrated that the proposed AFB1 immunosensor was able to differentiate between these other fungal mycotoxins. The novel electrochemical immunosensor approach has the potential for rapid sample screening in a portable, disposable format, thus contributing to the requirement for effective prevention and the control of aflatoxin B1 in pistachios.
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Althagafi II, Ahmed SA, El-Said WA. Fabrication of gold/graphene nanostructures modified ITO electrode as highly sensitive electrochemical detection of Aflatoxin B1. PLoS One 2019; 14:e0210652. [PMID: 30650140 PMCID: PMC6334944 DOI: 10.1371/journal.pone.0210652] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 12/28/2018] [Indexed: 02/07/2023] Open
Abstract
Aflatoxins (AFs) are a family of fungal toxins that produced in food and feed by two Aspergillus species (Aspergillus flavus and Aspergillus parasiticus). Several techniques have been reported for AFs detection including high-pressure liquid chromatography, enzyme-linked immunosorbent assay, surface plasmon resonance and recombinant immune blotting assay. But, these methods are disadvantaged because they consumed a long time for analysis; in addition, they required a piece of complicated and expensive equipment. Therefore, developing of inexpensive sensors with high selectivity and sensitivity for detecting of AFs levels without extensive sample preparation has received great attention. Several electrochemical AFs sensors have been reported; however, there is still a need for developing a new, simple and rapid electrochemical AFs sensor. Here, we have developed a new AFs sensor based on Au nanostructures/graphene nanosheets modified ITO substrate that could enhance the Raman effect and the electrochemical conductivity. The modified electrode was prepared based on layer-by-layer electrochemical deposition method. AFs antibody was immobilized onto the Au nanostructures/graphene nanosheets; then it was used as a probe for rapid, simple and cheap detection of AFs level using Raman spectroscopy and electrochemical techniques. Our results demonstrated that the developed system showed a simple, easy and sensitive sensor for monitoring low concentrations of AFB1 with a detection limit of about 6.9 pg/mL, also it allowed the determination of AFB1 in spiked food samples.
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Affiliation(s)
- Ismail I. Althagafi
- Chemistry Department, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia
- * E-mail:
| | - Saleh A. Ahmed
- Chemistry Department, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia
- Department of Chemistry, Faculty of Science, Assiut University, Assiut, Egypt
| | - Waleed A. El-Said
- Department of Chemistry, Faculty of Science, Assiut University, Assiut, Egypt
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Paul Wacoo A, Wendiro D, Nanyonga S, Hawumba JF, Sybesma W, Kort R. Feasibility of A Novel On-Site Detection Method for Aflatoxin in Maize Flour from Markets and Selected Households in Kampala, Uganda. Toxins (Basel) 2018; 10:toxins10080327. [PMID: 30103499 PMCID: PMC6115733 DOI: 10.3390/toxins10080327] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 08/08/2018] [Accepted: 08/09/2018] [Indexed: 12/20/2022] Open
Abstract
In sub-Saharan Africa, there is a high demand for affordable and accessible methods for on-site detection of aflatoxins for appropriate food safety management. In this study, we validated an electrochemical immunosensor device by the on-site detection of 60 maize flour samples from six markets and 72 samples from households in Kampala. The immunosensor was successfully validated with a linear range from 0.7 ± 0.1 to 11 ± 0.3 µg/kg and limit of detection (LOD) of 0.7 µg/kg. The maize flour samples from the markets had a mean total aflatoxin concentration of 7.6 ± 2.3 µg/kg with approximately 20% of the samples higher than 10 µg/kg, which is the maximum acceptable level in East Africa. Further down the distribution chain, at the household level, approximately 45% of the total number contained total aflatoxin levels higher than the acceptable limit. The on-site detection method correlated well with the established laboratory-based HPLC and ELISA-detection methods for aflatoxin B1 with the correlation coefficients of 0.94 and 0.98, respectively. This study shows the feasibility of a novel on-site detection method and articulates the severity of aflatoxin contamination in Uganda.
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Affiliation(s)
- Alex Paul Wacoo
- Department of Molecular Cell Biology, VU University Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
- Yoba for Life Foundation, Hunzestraat 133-A, 1079 WB Amsterdam, The Netherlands.
- Department of Nursing, Muni University, P.O. Box 725 Arua, Uganda.
| | - Deborah Wendiro
- Department of Microbiology and Biotechnology Centre, Product Development Directory, Uganda Industrial Research Institute, P.O. Box 7086 Kampala, Uganda.
| | - Sarah Nanyonga
- Department of Chemistry, Faculty of Science, Kyambogo University, P.O. Box 1 Kyambogo, Uganda.
| | - Joseph F Hawumba
- Department of Biochemistry and Sports Science, School of Biological Sciences, College of Natural Sciences, Makerere University, P.O. Box 7082 Kampala, Uganda.
| | - Wilbert Sybesma
- Yoba for Life Foundation, Hunzestraat 133-A, 1079 WB Amsterdam, The Netherlands.
| | - Remco Kort
- Department of Molecular Cell Biology, VU University Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
- Yoba for Life Foundation, Hunzestraat 133-A, 1079 WB Amsterdam, The Netherlands.
- TNO, Microbiology and Systems Biology, Utrechtseweg 48, 3704 HE Zeist, The Netherlands.
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Zhang Q, Li X, Qian C, Dou L, Cui F, Chen X. Label-free electrochemical immunoassay for neuron specific enolase based on 3D macroporous reduced graphene oxide/polyaniline film. Anal Biochem 2017; 540-541:1-8. [PMID: 29113785 DOI: 10.1016/j.ab.2017.10.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 08/24/2017] [Accepted: 10/11/2017] [Indexed: 01/11/2023]
Abstract
The content of neuron specific enolase (NSE) in serum is considered to be an essential indicator of small cell lung cancer (SCLC). Here, a novel label-free electrochemical immunoassay for the detection of NSE based on the three dimensionally macroporous reduced graphene oxide/polyaniline (3DM rGO/PANI) film has been proposed. The 3DM rGO/PANI film was constructed by electrochemical co-deposition of GO and aniline into the interspaces of a sacrificial silica opal template modified Au slice. During the co-deposition, GO was successfully reduced by aniline and PANI could be deposited on the surfaces of rGO sheets. The ratio of rGO and PANI in the composite was also optimized to achieve the maximum electrochemical performance. The 3DM rGO/PANI composite provided larger specific surface area for the antibody immobilization, exhibited enhanced conductivity for electron transfer, and more important was that PANI acted as the electroactive probe for indicating the NSE concentration. Under the optimal conditions, a linear current response of PANI to NSE concentration was obtained over 0.5 pg mL-1-10.0 ng mL-1 with a detection limit of 0.1 pg mL-1. Moreover, the immunosensor showed excellent selectivity, good stability, satisfactory reproducibility and regeneration, and was employed to detect NSE in clinical serum specimens.
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Affiliation(s)
- Qi Zhang
- Geological Survey of Jiangsu Province, Nanjing 210018, PR China.
| | - Xiaoyan Li
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Chunhua Qian
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Li Dou
- Wuxi Public Security Bureau, Wuxi 214002, PR China
| | - Feng Cui
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Xiaojun Chen
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, PR China.
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Li X, Cao L, Zhang Y, Yan P, Kirk DW. Fabrication and Modeling of an Ultrasensitive Label Free Impedimetric Immunosensor for Aflatoxin B1 based on Protein A Self-assembly Modified Gold 3D Nanotube Electrode ensembles. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.07.088] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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A Low-Cost Label-Free AFB1 Impedimetric Immunosensor Based on Functionalized CD-Trodes. CHEMOSENSORS 2016. [DOI: 10.3390/chemosensors4030017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Fogel R, Limson J. Developing Biosensors in Developing Countries: South Africa as a Case Study. BIOSENSORS-BASEL 2016; 6:bios6010005. [PMID: 26848700 PMCID: PMC4810397 DOI: 10.3390/bios6010005] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/23/2016] [Accepted: 01/27/2016] [Indexed: 12/14/2022]
Abstract
A mini-review of the reported biosensor research occurring in South Africa evidences a strong emphasis on electrochemical sensor research, guided by the opportunities this transduction platform holds for low-cost and robust sensing of numerous targets. Many of the reported publications centre on fundamental research into the signal transduction method, using model biorecognition elements, in line with international trends. Other research in this field is spread across several areas including: the application of nanotechnology; the identification and validation of biomarkers; development and testing of biorecognition agents (antibodies and aptamers) and design of electro-catalysts, most notably metallophthalocyanine. Biosensor targets commonly featured were pesticides and metals. Areas of regional import to sub-Saharan Africa, such as HIV/AIDs and tuberculosis diagnosis, are also apparent in a review of the available literature. Irrespective of the targets, the challenge to the effective deployment of such sensors remains shaped by social and economic realities such that the requirements thereof are for low-cost and universally easy to operate devices for field settings. While it is difficult to disentangle the intertwined roles of national policy, grant funding availability and, certainly, of global trends in shaping areas of emphasis in research, most notable is the strong role that nanotechnology, and to a certain extent biotechnology, plays in research regarding biosensor construction. Stronger emphasis on collaboration between scientists in theoretical modelling, nanomaterials application and or relevant stakeholders in the specific field (e.g., food or health monitoring) and researchers in biosensor design may help evolve focused research efforts towards development and deployment of low-cost biosensors.
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Affiliation(s)
- Ronen Fogel
- Biotechnology Innovation Centre, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
| | - Janice Limson
- Biotechnology Innovation Centre, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
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Castillo G, Spinella K, Poturnayová A, Šnejdárková M, Mosiello L, Hianik T. Detection of aflatoxin B1 by aptamer-based biosensor using PAMAM dendrimers as immobilization platform. Food Control 2015. [DOI: 10.1016/j.foodcont.2014.12.008] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Hu H, Cao L, Li Q, Ma K, Yan P, Kirk DW. Fabrication and modeling of an ultrasensitive label free impedimetric immunosensor for Aflatoxin B1based on poly(o-phenylenediamine) modified gold 3D nano electrode ensembles. RSC Adv 2015. [DOI: 10.1039/c5ra06300k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An ultrasensitive label free impedimetric immunosensor for AFB1detection was fabricated based on poly(o-phenylenediamine) (PoPD) electropolymerized film modified gold three dimensional nanoelectrode ensembles (3DNEEs).
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Affiliation(s)
- Haifeng Hu
- Department of Applied Chemistry
- Harbin Institute of Technology
- Weihai campus
- Weihai
- 264209 China
| | - Lixin Cao
- Department of Applied Chemistry
- Harbin Institute of Technology
- Weihai campus
- Weihai
- 264209 China
| | - Qingchuan Li
- Department of Applied Chemistry
- Harbin Institute of Technology
- Weihai campus
- Weihai
- 264209 China
| | - Kan Ma
- Department of Applied Chemistry
- Harbin Institute of Technology
- Weihai campus
- Weihai
- 264209 China
| | - Peisheng Yan
- Department of Bioengineering
- Harbin Institute of Technology
- Weihai campus
- Weihai
- 264209 China
| | - Donald W. Kirk
- Department of Chemical Engineering and Applied Chemistry
- University of Toronto
- Toronto
- M5S 3E5 Canada
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Wang D, Hu W, Xiong Y, Xu Y, Ming Li C. Multifunctionalized reduced graphene oxide-doped polypyrrole/pyrrolepropylic acid nanocomposite impedimetric immunosensor to ultra-sensitively detect small molecular aflatoxin B1. Biosens Bioelectron 2015; 63:185-189. [DOI: 10.1016/j.bios.2014.06.070] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 06/23/2014] [Accepted: 06/30/2014] [Indexed: 11/29/2022]
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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 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] [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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Graphene Oxide-Based Biosensor for Food Toxin Detection. Appl Biochem Biotechnol 2014; 174:960-70. [DOI: 10.1007/s12010-014-0965-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 05/15/2014] [Indexed: 01/07/2023]
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Ali MAI, El Zubeir IEM, Fadel Elseed AMA. Aflatoxin M1 in raw and imported powdered milk sold in Khartoum state, Sudan. FOOD ADDITIVES & CONTAMINANTS PART B-SURVEILLANCE 2014; 7:208-12. [PMID: 25029404 DOI: 10.1080/19393210.2014.887149] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The aim of this study is to determine the level of contamination of aflatoxin M1 (AFM1) in raw and imported powdered milk in Khartoum state, Sudan. Thirty-five samples of fresh cow milk were collected from different farms, based on the source of concentrated feed introduced to the dairy cows (locally vs. commercially produced) and the size of the farm (≤ 50 vs. >50 cows/farm). Also 12 samples of powdered milk were obtained from repacking companies in Khartoum state. The samples were analysed by a fluorometer, using the Vicam method. AFM1 was detected in all raw and powdered milk samples. Almost 50% of the contaminated powdered milk samples and all the raw milk samples exceeded the European Union limit of 0.05 µg/kg whereas 33% of the contaminated powdered milk samples and 77% of the raw milk samples exceeded the limit of Codex regulations (0.5 µg/kg). The results revealed that the concentration of AFM1 is affected significantly (P < 0.05) by the source of concentrated feed (locally produced or purchased) but not by the farm size. It was concluded that the levels of AFM1 in the milk samples indicated that the feeds offered to the cows were contaminated with aflatoxin B1 to such a level that it might cause a serious health problem to the public. Therefore, there is a need to limit the exposure to aflatoxin by imposing regulatory limits, as well as further studies on large scale bases are needed to investigate the amount of AFM1 in milk and dairy products.
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Affiliation(s)
- M A I Ali
- a Sudanese Standards and Metrology Organization, Airport branch , Khartoum , Sudan
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18
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Li J, Liu G, Zhang W, Cheng W, Xu H, Ding S. Competitive detection of pregnancy-associated plasma protein-A in serum using functional single walled carbon nanotubes/chitosan-based electrochemical immunosensor. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2013.09.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
Electrically conducting polymers (ECPs) are finding applications in various fields of science owing to their fascinating characteristic properties such as binding molecules, tuning their properties, direct communication to produce a range of analytical signals and new analytical applications. Polyaniline (PANI) is one such ECP that has been extensively used and investigated over the last decade for direct electron transfer leading towards fabrication of mediator-less biosensors. In this review article, significant attention has been paid to the various polymerization techniques of polyaniline as a transducer material, and their use in enzymes/biomolecules immobilization methods to study their bio-catalytic properties as a biosensor for potential biomedical applications.
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Electrochemical affinity biosensors for detection of mycotoxins: A review. Biosens Bioelectron 2013; 49:146-58. [PMID: 23743326 DOI: 10.1016/j.bios.2013.05.008] [Citation(s) in RCA: 195] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 04/26/2013] [Accepted: 05/02/2013] [Indexed: 11/22/2022]
Abstract
This review discusses the current state of electrochemical biosensors in the determination of mycotoxins in foods. Mycotoxins are highly toxic secondary metabolites produced by molds. The acute toxicity of these results in serious human and animal health problems, although it has been only since early 1960s when the first studied aflatoxins were found to be carcinogenic. Mycotoxins affect a broad range of agricultural products, most important cereals and cereal-based foods. A majority of countries, mentioning especially the European Union, have established preventive programs to control contamination and strict laws of the permitted levels in foods. Official methods of analysis of mycotoxins normally requires sophisticated instrumentation, e.g. liquid chromatography with fluorescence or mass detectors, combined with extraction procedures for sample preparation. For about sixteen years, the use of simpler and faster analytical procedures based on affinity biosensors has emerged in scientific literature as a very promising alternative, particularly electrochemical (i.e., amperometric, impedance, potentiometric or conductimetric) affinity biosensors due to their simplicity and sensitivity. Typically, electrochemical biosensors for mycotoxins use specific antibodies or aptamers as affinity ligands, although recombinant antibodies, artificial receptors and molecular imprinted polymers show potential utility. This article deals with recent advances in electrochemical affinity biosensors for mycotoxins and covers complete literature from the first reports about sixteen years ago.
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21
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Sensitive and multiplexed analysis of aflatoxins using time-of-flight secondary ion mass spectrometry. BIOCHIP JOURNAL 2012. [DOI: 10.1007/s13206-012-6105-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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22
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Chen X, Chen Z, Tian R, Yan W, Yao C. Glucose biosensor based on three dimensional ordered macroporous self-doped polyaniline/Prussian blue bicomponent film. Anal Chim Acta 2012; 723:94-100. [PMID: 22444579 DOI: 10.1016/j.aca.2012.02.032] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 02/13/2012] [Accepted: 02/15/2012] [Indexed: 11/19/2022]
Abstract
In this paper, a three dimensional ordered macroporous self-doped polyaniline/Prussian blue (3DOM SPAN/PB) bicomponent film was fabricated via the inverted crystal template technique using step-by-step electrodeposition. In this bicomponent film, PB not only acted as a redox mediator, but also presented increased stability in neutral or weak alkaline solution by the protection of SPAN layer on the top. A novel glucose biosensor was fabricated based on the large active surface area and excellent conductivity possessed by the 3DOM SPAN/PB film. The applying experimental conditions of the glucose biosensor have been optimized. Under the optimal conditions, the biosensor showed a wide linear range over three orders of magnitude in glucose concentrations (from 2 to 1600 μM) and a low detection limit of 0.4 μM. Moreover, the biosensor exhibited short response time, high selectivity and excellent operation stability, which can be applied to detect the blood sugar in real samples without any pretreatment.
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Affiliation(s)
- Xiaojun Chen
- College of Sciences, Nanjing University of Technology, Nanjing 210009, PR China.
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23
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Lee I, Park SY, Kim MJ, Yun M. Materialization of single multicomposite nanowire: entrapment of ZnO nanoparticles in polyaniline nanowire. NANOSCALE RESEARCH LETTERS 2011; 6:393. [PMID: 21711928 PMCID: PMC3211487 DOI: 10.1186/1556-276x-6-393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 05/20/2011] [Indexed: 05/31/2023]
Abstract
We present materialization of single multicomposite nanowire (SMNW)-entrapped ZnO nanoparticles (NPs) via an electrochemical growth method, which is a newly developed fabrication method to grow a single nanowire between a pair of pre-patterned electrodes. Entrapment of ZnO NPs was controlled via different conditions of SMNW fabrication such as an applied potential and mixture ratio of NPs and aniline solution. The controlled concentration of ZnO NP results in changes in the physical properties of the SMNWs, as shown in transmission electron microscopy images. Furthermore, the electrical conductivity and elasticity of SMNWs show improvement over those of pure polyaniline nanowire. The new nano-multicomposite material showed synergistic effects on mechanical and electrical properties, with logarithmical change and saturation increasing ZnO NP concentration.
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Affiliation(s)
- Innam Lee
- Department of Electrical and Computer Engineering, University of Pittsburgh, Benedum Hall 348, Pittsburgh, PA 15261, USA
| | - Seong Yong Park
- Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Moon J Kim
- Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Minhee Yun
- Department of Electrical and Computer Engineering, University of Pittsburgh, Benedum Hall 348, Pittsburgh, PA 15261, USA
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Muchindu M, Iwuoha E, Pool E, West N, Jahed N, Baker P, Waryo T, Williams A. Electrochemical Ochratoxin A Immunosensor System Developed on Sulfonated Polyaniline. ELECTROANAL 2010. [DOI: 10.1002/elan.201000452] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Maragos C, Busman M. Rapid and advanced tools for mycotoxin analysis: a review. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2010; 27:688-700. [DOI: 10.1080/19440040903515934] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Maragos C. Biosensors for mycotoxin analysis: recent developments and future prospects. WORLD MYCOTOXIN J 2009. [DOI: 10.3920/wmj2008.1117] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The toxicity and prevalence of mycotoxins in commodities and foods has necessitated the development of rapid methods in order to ensure the protection of human food and animal feed supplies. Testing for mycotoxins can be accomplished by many techniques that range from determinative tests in which the presence of the toxin is confirmed, to presumptive tests in which the presence of the toxin is inferred from the presence of markers. This review focuses on tests that fall into a third category, namely indirect assays, where the presence of the toxin is established by it's interaction with an intermediary. Such intermediaries include biological materials that bind mycotoxins, such as antibodies, as well as synthetic materials such as polymers and man-made peptides. The diversity of assays within this category is extraordinary and includes assays based upon traditional microwell formats, microbeads, membranes, electrodes, wave-guides, and solution-phase assays. The microbead format includes platforms as diverse as flow injection immunoassays, tandem column immunoassays, and immunoaffinity columns. The membrane-based formats include flow-through as well as lateral-flow assays. The electrode-based formats incorporate miniaturised immunoassays with electrochemical endpoints. The wave-guide-based devices include formats such as surface plasmon resonance, and fluorescence array biosensors, and the solution phase formats include homogeneous assays such as fluorescence polarisation immunoassay. The breadth of technologies brought to bear upon solving the need for rapid, accurate, detection of mycotoxins is impressive and includes technologies currently available commercially and those which appear poised to enter the marketplace.
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Affiliation(s)
- C. Maragos
- Mycotoxin Research Unit, National Center for Agricultural Utilization Research, ARS, USDA, 1815 N. University St., Peoria, IL 61604, USA
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29
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A signal-amplified electrochemical immunosensor for aflatoxin B1 determination in rice. Anal Biochem 2009; 387:82-6. [DOI: 10.1016/j.ab.2008.12.030] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2008] [Revised: 12/20/2008] [Accepted: 12/24/2008] [Indexed: 11/23/2022]
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30
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Chitosan/polyaniline hybrid conducting biopolymer base impedimetric immunosensor to detect Ochratoxin-A. Biosens Bioelectron 2009; 24:1700-5. [DOI: 10.1016/j.bios.2008.08.046] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 08/16/2008] [Accepted: 08/29/2008] [Indexed: 11/18/2022]
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Shephard G, Berthiller F, Dorner J, Krska R, Lombaert G, Malone B, Maragos C, Sabino M, Solfrizzo M, Trucksess M, van Egmond H, Whitaker T. Developments in mycotoxin analysis: an update for 2007-2008. WORLD MYCOTOXIN J 2009. [DOI: 10.3920/wmj2008.1095] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This review highlights developments in mycotoxin analysis and sampling over a period between mid-2007 and mid-2008. It covers the major mycotoxins: aflatoxins, Alternaria toxins, cyclopiazonic acid, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Some aspects of natural occurrence, particularly if linked to novel aspects of analytical methods, are also included. The review demonstrates the rise of LC-MS methods, the continuing interest in developing alternative and rapid methods and the modification of well-established mycotoxin analytical methods by individual laboratories to meet their own requirements.
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Affiliation(s)
- G. Shephard
- PROMEC Unit, Medical Research Council, P.O. Box 19070, Tygerberg 7505, South Africa
| | - F. Berthiller
- Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Applied Life Sciences Vienna, Center for Analytical Chemistry, Christian Doppler Laboratory for Mycotoxin Research, Konrad Lorenz Str. 20, 3430 Tulln, Austria
| | - J. Dorner
- USDA, ARS, National Peanut Research Laboratory, P.O. Box 509, 1011 Forrester Dr. SE, Dawson, GA 31742, USA
| | - R. Krska
- Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Applied Life Sciences Vienna, Center for Analytical Chemistry, Christian Doppler Laboratory for Mycotoxin Research, Konrad Lorenz Str. 20, 3430 Tulln, Austria
| | - G. Lombaert
- Health Canada, 510 Lagimodiere Blvd., Winnipeg, MB, R2J 3Y1, Canada
| | - B. Malone
- Trilogy Analytical Laboratory, 111 West Fourth Street, Washington, MO 63090, USA
| | - C. Maragos
- USDA, ARS National Center for Agricultural Utilization Research, 1815 N. University St., Peoria, IL 61604, USA
| | - M. Sabino
- Instituto Adolfo Lutz, Av. Dr. Arnaldo 355, 01246-902, São Paulo/SP, Brazil
| | - M. Solfrizzo
- Institute of Sciences of Food Production, National Research Council, Via Amendola 122/o, 700126 Bari, Italy
| | - M. Trucksess
- US Food and Drug Administration, 5100 Paint Branch Parkway, College Park, MD 20740, USA
| | - H. van Egmond
- National Institute for Public Health & the Environment, Laboratory for Food and Residue Analysis (ARO), P.O. Box 1, 3720 BA Bilthoven, the Netherlands
| | - T. Whitaker
- USDA, ARS, N.C. State University, P.O. Box 7625, Raleigh, NC 27695-7625, USA
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An overview of conventional and emerging analytical methods for the determination of mycotoxins. Int J Mol Sci 2009; 10:62-115. [PMID: 19333436 PMCID: PMC2662450 DOI: 10.3390/ijms10010062] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 11/24/2008] [Accepted: 01/01/2009] [Indexed: 11/16/2022] Open
Abstract
Mycotoxins are a group of compounds produced by various fungi and excreted into the matrices on which they grow, often food intended for human consumption or animal feed. The high toxicity and carcinogenicity of these compounds and their ability to cause various pathological conditions has led to widespread screening of foods and feeds potentially polluted with them. Maximum permissible levels in different matrices have also been established for some toxins. As these are quite low, analytical methods for determination of mycotoxins have to be both sensitive and specific. In addition, an appropriate sample preparation and pre-concentration method is needed to isolate analytes from rather complicated samples. In this article, an overview of methods for analysis and sample preparation published in the last ten years is given for the most often encountered mycotoxins in different samples, mainly in food. Special emphasis is on liquid chromatography with fluorescence and mass spectrometric detection, while in the field of sample preparation various solid-phase extraction approaches are discussed. However, an overview of other analytical and sample preparation methods less often used is also given. Finally, different matrices where mycotoxins have to be determined are discussed with the emphasis on their specific characteristics important for the analysis (human food and beverages, animal feed, biological samples, environmental samples). Various issues important for accurate qualitative and quantitative analyses are critically discussed: sampling and choice of representative sample, sample preparation and possible bias associated with it, specificity of the analytical method and critical evaluation of results.
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Owino JHO, Arotiba OA, Hendricks N, Songa EA, Jahed N, Waryo TT, Ngece RF, Baker PGL, Iwuoha EI. Electrochemical Immunosensor Based on Polythionine/Gold Nanoparticles for the Determination of Aflatoxin B₁. SENSORS (BASEL, SWITZERLAND) 2008; 8:8262-8274. [PMID: 27873987 PMCID: PMC3791018 DOI: 10.3390/s8128262] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 12/01/2008] [Accepted: 12/02/2008] [Indexed: 11/24/2022]
Abstract
An aflatoxin B₁ (AFB₁) electrochemical immunosensor was developed by the immobilisation of aflatoxin B₁-bovine serum albumin (AFB₁-BSA) conjugate on a polythionine (PTH)/gold nanoparticles (AuNP)-modified glassy carbon electrode (GCE). The surface of the AFB₁-BSA conjugate was covered with horseradish peroxidase (HRP), in order to prevent non-specific binding of the immunosensors with ions in the test solution. The AFB₁ immunosensor exhibited a quasi-reversible electrochemistry as indicated by a cyclic voltammetric (CV) peak separation (ΔEp) value of 62 mV. The experimental procedure for the detection of AFB₁ involved the setting up of a competition between free AFB₁ and the immobilised AFB₁-BSA conjugate for the binding sites of free anti-aflatoxin B₁ (anti-AFB₁) antibody. The immunosensor's differential pulse voltammetry (DPV) responses (peak currents) decreased as the concentration of free AFB₁ increased within a dynamic linear range (DLR) of 0.6 - 2.4 ng/mL AFB₁ and a limit of detection (LOD) of 0.07 ng/mL AFB₁. This immunosensing procedure eliminates the need for enzyme-labeled secondary antibodies normally used in conventional ELISA-based immunosensors.
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Affiliation(s)
- Joseph H O Owino
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa
| | - Omotayo A Arotiba
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa
| | - Nicolette Hendricks
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa
| | - Everlyne A Songa
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa
| | - Nazeem Jahed
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa
| | - Tesfaye T Waryo
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa
| | - Rachel F Ngece
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa
| | - Priscilla G L Baker
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa
| | - Emmanuel I Iwuoha
- SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
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An Electrochemical DNA Biosensor Developed on a Nanocomposite Platform of Gold and Poly(propyleneimine) Dendrimer. SENSORS 2008; 8:6791-6809. [PMID: 27873900 PMCID: PMC3787416 DOI: 10.3390/s8116791] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 10/22/2008] [Accepted: 10/27/2008] [Indexed: 11/26/2022]
Abstract
An electrochemical DNA nanobiosensor was prepared by immobilization of a 20mer thiolated probe DNA on electro-deposited generation 4 (G4) poly(propyleneimine) dendrimer (PPI) doped with gold nanoparticles (AuNP) as platform, on a glassy carbon electrode (GCE). Field emission scanning electron microscopy results confirmed the co-deposition of PPI (which was linked to the carbon electrode surface by C-N covalent bonds) and AuNP ca 60 nm. Voltammetric interrogations showed that the platform (GCE/PPI-AuNP) was conducting and exhibited reversible electrochemistry (E°′ = 235 mV) in pH 7.2 phosphate buffer saline solution (PBS) due to the PPI component. The redox chemistry of PPI was pH dependent and involves a two electron, one proton process, as interpreted from a 28 mV/pH value obtained from pH studies. The charge transfer resistance (Rct) from the electrochemical impedance spectroscopy (EIS) profiles of GCE/PPI-AuNP monitored with ferro/ferricyanide (Fe(CN)63-/4-) redox probe, decreased by 81% compared to bare GCE. The conductivity (in PBS) and reduced Rct (in Fe(CN)63-/4-) values confirmed PPI-AuNP as a suitable electron transfer mediator platform for voltammetric and impedimetric DNA biosensor. The DNA probe was effectively wired onto the GCE/PPI-AuNP via Au-S linkage and electrostatic interactions. The nanobiosensor responses to target DNA which gave a dynamic linear range of 0.01 - 5 nM in PBS was based on the changes in Rct values using Fe(CN)63-/4- redox probe.
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Pohanka M, Malir F, Roubal T, Kuca K. Detection of Aflatoxins in Capsicum Spice Using an Electrochemical Immunosensor. ANAL LETT 2008. [DOI: 10.1080/00032710802350518] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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An electrochemical enzyme immunoassay for aflatoxin B1 based on bio-electrocatalytic reaction with room-temperature ionic liquid and nanoparticle-modified electrodes. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s11694-008-9040-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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