After the immobilization of the antibody, the electrodes were rinsed with PBS in order to remove physically-unbound antibody, and then, 40 L of BSA (0

After the immobilization of the antibody, the electrodes were rinsed with PBS in order to remove physically-unbound antibody, and then, 40 L of BSA (0.04 mgL?1) were applied for 2 h at room temperature to block nonspecific binding sites. selected substrates, but Remodelin have never been associated with human or other animal disease. Fumonisins are produced by a number of fusarium species, especially (previously fusarium moniliforme = sp. [1]. Actually, over twenty-eight fumonisins have been isolated and classified into four series known as Remodelin A, B, C and P. produces several mycotoxins, the most prominent of which is called fumonisin B1 (FB1) [7]. Fumonisin B1 is the diester of propane-1,2,3-tricarboxylic acid (TCA) and a pentahydroxyeicosane in which the C14 and C15 hydroxy groups of Remodelin the latter are esterified with the terminal carboxy group of TCA. While some toxin synthesis may occur during transportation and storage, unsurprisingly, Fusarium mycotoxins found in food are produced mainly in the field, where temperature and moisture conditions are crucial factors that favor fungal infection and toxin synthesis [7]. FB1, FB2 and FB3 are the principal fumonisins analyzed as natural contaminants of cereals [8, 9] and can trigger serious human and animal diseases [10,11]. Exposure to fumonisin B1 (FB1) in maize causes leukoencephalomalacia (LEM) in horses and pulmonary edema in pigs. Leukoencephalomalacia has been reported in many countries, including the USA, Argentina, Brazil, Egypt, South Africa and China. FB1 can also harm the central nervous system, liver, pancreas, kidney and lungs in a number of animal species. For example, the presence of fumonisins in maize has been linked to the occurrence of human esophageal cancer in the Transkei, South Africa and China. The relationship between exposure to in home-grown maize and the incidence of esophageal cancer was studied in the Transkei from 1976 to 1986 [12]. Fumonisins have been traditionally analyzed by chromatographic methods, such as thin layer chromatography (TLC), liquid chromatography (LC), liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC), which are expensive and time-consuming methods and, despite their higher sensitivity and specificity, require appropriate instrumentation and trained personnel. As a less expensive alternative, the ELISA method has a higher detection limit, but the requirements include a stable source of antibodies and incubation time for enzyme-substrate reactions, rendering it unsuitable T for use in the field [13,14]. Previously, we developed an impedimetric immunosensor for the Remodelin detection of fumonisins on poly(2,5-dimethoxyaniline)-multi-walled carbon nanotubes doped with palladium telluride quantum dots onto a glassy carbon electrode surface. However it had relatively low stability [15]. Very recently, Yang developed a practical detection method and sensitive electrochemical immunosensor for detecting fumonisin B1 (FB1) in corn using a single-walled carbon nanotube/chitosan composite and differential pulse voltammetry (DPV) measurements. This method, however, only allowed for the indirect identification of FB1 and also exhibited low stability [16]. Consequently, there is still a need for an immunosensor, for the detection and quantification of FB1 in food/feed, that is low cost, convenient and rapid with improved stability and higher sensitivity, such as the one presented in this study, which is based on a poly(dimethoxyaniline)-multi-walled carbon nanotube (PDMA-MWCNT) nanocomposite. Interactions between polyaniline (PANI) and carbon nanotubes (CNT) in the composites can occur in a number of ways. It was first suggested that the attachment of aniline radicals, generated during electrochemical oxidative polymerization, onto the CNT lattice occurred at defect sites [17]. However, since then, it has been shown that the carboxylic acid sites at the acid-treated CNT are the most likely sites of interaction with the aniline monomer [18]. Electrical, thermal and mechanical properties observed in PANI-CNT composites are intermediate between pure PANI and CNT and are dependent on CNT content and the extent of its integration with PANI. Thus, the electrochemical properties of a PANI-CNT composite are enhanced compared to the two individual components. For instance, electrochemical growth together with the values of the redox and capacitive currents of the composites are several-fold greater than the pure PANI electrode [17,18]. The same behavior is also observed in composites of CNT with substituted PANI derivatives, where the extent of the increase in current depends on the nature of the substituent present on the aniline ring [17]. Such a remarkable current enhancement appears to Remodelin be unique to PANI-CNT composites and has not been observed for any other conjugated polymer-CNT composite. This synergistic performance of PANI-CNT composites has been beneficial in certain applications, including fuel cells, batteries, supercapacitors, sensors and organic devices and electronics, where for example, PANI can be used as a.