Label Free Poly(2,5-dimethoxyaniline)–Multi-Walled Carbon Nanotubes Impedimetric Immunosensor for Fumonisin B1 Detection

Abstract

An impedimetric immunosensor for fumonisin B1 (FB1) was developed from a poly(2,5-dimethoxyaniline)-multi-walled carbon nanotube (PDMA-MWCNT) composite on the surface of glassy carbon electrode (GCE). The composite was prepared electrochemically and characterized using cyclic voltammetry. The preparation of the FB1 immunosensor involved the drop-coating of a bovine serum albumin mixture of the anti-fumonisin antibody (anti-Fms) onto the composite polymer-modified GCE. The electrochemical impedance spectroscopy (EIS) responses of the FB1 immunosensor (GCE/PDMA-MWCNT/anti-Fms) have a linear range of 7 to 49 ng·L−1, and the corresponding sensitivity and detection limits are 0.272 kΩ L·ng−1 and 3.8 pg·L−1, respectively. The limit of detection of the immunosensor for certified corn sample (i.e., certified reference material) is 0.014 ppm FB1, which is in excellent agreement with the value published by the vendors and significantly more accurate than that obtained with enzyme-linked immunosorbent assay (ELISA).

Aptamers as the Agent in Decontamination Assays (Apta-Decontamination Assays): From the Environment to the Potential Application In Vivo

“…Environmental contamination has been a major concern worldwide for the past two centuries [ 1 ]. Major environmental contaminants are organic compounds such as small organic and inorganic pollutants, pharmaceuticals, personal care products, toxins of microbial origin, and pathogens [ 2 – 5 ]. These environmental contaminants have severe impact on quality of food, air, and water, in turn exerting mild to severe deadly effects on human and animals.…”

Aptamer-Based Detection of Fumonisin B1: A Systematic Comparison with Conventional and Other Novel Methods

“…Nevertheless, some sensors qualified as fast required overnight steps and long incubation times for the whole system arrangement, especially when the synthesis of nanoparticles and drying phases were required. Assay times below ten minutes were achieved through chromatographic, immunoassays, and some innovative methods, nonetheless the more sensitive assays were secured with aptamer-based biosensors [170,177,200], immunosensors with carbon nanotubes [101,109], and molecularly imprinted polymer nanoparticles (MIPs) [191], as indicated in Figures 4a and 4c.…”

“…Despite the fact that the use of antibodies with electrochemical readouts was advantageous for achieving some of the lowest LODs for fumonisin B1, equivalent to 4.6e-7 and 3.7e-6 µg/L [101,109], these immunosensors were not included in the principal component analysis (PCA), as no assay time was reported in either case. Hence, as indicated in Figure 5, LC-MS [56,75], immunoassays with optical [99,107,135], Raman (due to its quick procedure) [140], fluorescent readouts [147] and electrochemical MIPs [191] were correlated to the combination of low LODs with short assay times.…”

“…This antigen-antibody interaction has been used, optimized and improved over the years; and commercially available ELISA kits and standardized ELISA protocols are still applied for method validation and comparison with novel biosensing developments [128,130,143,166,170]. As presented in Fig 4, electrochemical immunosensors have portrayed some of the lowest LODs [101,109]. For instance, the signal of an impedance sensor was modified by depositing quantum dotscarbon nanotubes on a glassy carbon electrode (GCE) for the immobilization of the corresponding antibody.…”

Developments in mycotoxin analysis: an update for 2019-2020

“…An advantage of homogeneous assays is that there is no need to separate 'bound' and 'unbound' labels. One mechanism for avoiding the separation step is to measure the binding of the toxin to the recognition element, as was done recently with a label-free electrochemical immunosensor for FB 1 (Masikini et al, 2016). The device was based upon the deposition of a polymer onto a glassy carbon electrode.…”