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Electrochemical Fabrication of Carbon Nanomaterial and Conducting Polymer Composites for Chemical Sensing
Published in Di Wei, Electrochemical Nanofabrication, 2017
Zhanna A. Boeva, Rose-Marie Latonen, Tom Lindfors, Zekra Mousavi
Composite films consisting of PPy, graphene derivatives and proteins has been used for the detection of toxins [110, 111], and protein biomarkers such as myoglobin [112]. The fabrication of an aflatoxin B1 biosensor consists of a five step procedure: first RGO is deposited electrochemically onto the surface of a Au electrode, then the conducting polymer poly(2,5-di-(2-thienyl)-1-pyrrole-1-(p-benzoic acid)) (polyDPB) is electrochemically deposited on the RGO surface [112]. On the layered structure of polyDPB-RGO, AuNPs were deposited potentiostatically and the aflatoxin B1 antibody was then covalently attached to the carboxylic groups of the ECP using carbodiimide chemistry. The composite film is thereafter coated with a dispersion of chitosan in IL. It is shown that aflatoxin B1 can be detected impedimetrically in femtomolar concentrations due to the high specificity of the binding of the toxin with its antibody. The aflatoxin B1 sensor does not show any sensitivity to the other toxins of the aflatoxin family and had very good signal reproducibility.
Electrochemical Transducers for Biosensors
Published in Sibel A. Ozkan, Bengi Uslu, Mustafa Kemal Sezgintürk, Biosensors, 2023
Ali A. Ensafi, Parisa Nasr-Esfahani
Developing low-cost and rapid methods for determining toxicities in the environment and industrial wastewaters is essential. Aflatoxins are natural fungal toxins produced by Aspergillus fungi. These fungi usually infect maize, wheat, barley, rice, tree nuts, and groundnuts easily. Among different types of aflatoxins, aflatoxin B1 is the most toxic and responsible for liver cancer in animals. Li et al. developed a potentiometric biosensor for aflatoxin B1 detection in food. Aflatoxin B1-bovine serum albumin conjugate was immobilized on a glassy carbon electrode, and gold nanoparticles were functionalized with polyclonal anti-aflatoxin B1 antibody. The basis of this sensor is that with adding target aflatoxin B1, competitive immunobinding occurs between the analyte and aflatoxin B1-bovine serum albumin for the labelled anti-aflatoxin B1 antibody on the gold nanoparticles. The measured output potential is linearly proportional to the logarithm of aflatoxin B1 concentration in the range of 0.1 to 5.0 μg.kg-1, and the detection limit was obtained 87 ng.kg-1. To assess the accuracy of the immunosensor, it was applied for the detection of aflatoxin B1 levels in peanut samples (65). The toxicity detection of pollutants in water has significant importance for ecosystems and human health. Zhang’s group reported a potentiometric biosensor for toxicity detection in water. They used the ammonia-oxidizing bacterium Nitrosomonas europaea as a bioreceptor and a polymeric membrane ammonium-selective electrode as a transducer. The molecular recognition and transduction processes were performed individually using the ammonia-oxidizing bacterium cells were immobilized on polyethersulfone membranes. This biosensor acts based on the inhibition effects of toxicants on the activity of the ammonia-oxidizing bacterium, which is evaluated by measuring the ammonium consumption rates with the ammonium-selective membrane electrode. The developed sensor represented good sensitivity, simplicity, and speed for toxicity detection in water (66).
Effects of aflatoxin B1 exposure on sperm in rodents: a systematic review and meta-analysis
Published in International Journal of Environmental Health Research, 2022
Mahdi Fasihi-Ramandi, Ghazal Bayat, Reza Kachuei, Reza Golmohammadi
Aflatoxin B1 is considered to be more toxic than all other types of aflatoxins (Huang et al. 2020), which are potentially associated with male reproductive damages through several pathways. In this regard, some animal studies indicated that aflatoxin B1 prevents antioxidant activity against free radicals, resulting in testicular degeneration and decreased sperm concentration and motility. Moreover, aflatoxin B1 disrupts the metabolism of essential hormones involved in sperm production such as testosterone, eventually impairs reproductive function (Abdel-Aziem et al. 2011; Adedara et al. 2014; Huang et al. 2020). Aflatoxin B1 decreased the amount of sperm production in Nigerian goats, possibly due to its toxic effects on testosterone levels (Ewuola et al. 2014).