Preparation, characterization of Fe3O4 at TiO2 magnetic nanoparticles and their application for immunoassay of biomarker of exposure to organophosphorus pesticides

Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China.
Biosensors & Bioelectronics (Impact Factor: 6.45). 10/2013; DOI: 10.1016/j.bios.2012.09.047
Source: PubMed

ABSTRACT Novel Fe(3)O(4) at TiO(2) magnetic nanoparticles were prepared and developed for a new nanoparticle-based immunosensor for electrochemical quantification of organophosphorylated butyrylcholinesterase (BChE) in plasma, a specific biomarker of exposure to organophosphorus (OP) agents. The Fe(3)O(4) at TiO(2) nanoparticles were synthesized by hydrolysis of tetrabutyltitanate on the surface of Fe(3)O(4) magnetic nanospheres, and characterized by attenuated total reflection Fourier-transform infrared spectra, transmission electron microscope and X-ray diffraction. The functional Fe(3)O(4) at TiO(2) nanoparticles were performed as capture antibody to selectively enrich phosphorylated moiety instead of phosphoserine antibody in the traditional sandwich immunoassays. The secondary recognition was performed by quantum dots (QDs)-tagged anti-BChE antibody (QDs-anti-BChE). With the help of a magnet, the resulting sandwich-like complex, Fe(3)O(4) at TiO(2)/OP-BChE/QDs-anti-BChE, was easily isolated from sample solutions and the released cadmium ions were detected on a disposable screen-printed electrode (SPE). The binding affinities were investigated by both surface plasmon resonance (SPR) and square wave voltammetry (SWV). This method not only avoids the drawback of unavailability of commercial OP-specific antibody but also amplifies detection signal by QDs-tags together with easy separation of samples by magnetic forces. The proposed immunosensor yields a linear response over a broad OP-BChE concentrations range from 0.02 to 10nM, with detection limit of 0.01nM. Moreover, the disposable nanoparticle-based immunosensor has been validated with human plasma samples. It offers a new method for rapid, sensitive, selective and inexpensive screening/evaluating exposure to OP pesticides and nerve agents.


Available from: Dan Du, Apr 21, 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: A review of literature published in 2013 on analytical methods for pesticides, including mostly insecticides but also some herbicides, is presented here and includes papers on analytical methods such as biochemical assays and immunoassays, electrochemical methods, review articles on analytical methods, chromatographic or mass spectrometric techniques, spectrophotometric techniques, fluorescence, and chemiluminescence techniques. There is also a section on extraction techniques because of their importance in pesticide residue analyses.
    Water Environment Research 10/2014; 86(10). DOI:10.2175/106143014X13975035526185 · 1.00 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A simple and sensitive enhanced chemiluminescence enzyme linked immunosorbent assay (ECL-ELISA) has been developed for the detection of phosmet (PMT), azinphos-methyl (APM) and azinphos-ethyl (APE) residues in vegetable samples. The concentration of the coating antibody and enzyme tracer as well as the effects of the pH value, ionic strength and organic solvent were studied. The measured sensitivities (IC50) of PMT, APM and APE were 8.56, 9.04 and 25.34 μg L−1, respectively. High throughput screening for PMT, APM, and APE residues was achieved with good accuracy by means of the ECL-ELISA. The measurement time of the ECL-ELISA method was 5-10% shorter than that of the traditional ELISA method, and the sensitivity of detection was 2-3.5 times lower than that of the traditional method.
    Analytical methods 01/2013; 5(21):5938. DOI:10.1039/c3ay40825f · 1.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Carcinogen contaminations in the food chain, for example heavy metal ions, pesticides, acrylamide, and mycotoxins, have caused serious health problems. A major objective of food-safety research is the identification and prevention of exposure to these carcinogens, because of their impossible-to-reverse tumorigenic effects. However, carcinogen detection is difficult because of their trace-level presence in food. Thus, reliable and accurate separation and determination methods are essential to protect food safety and human health. This paper summarizes the state of the art in separation and determination methods for analyzing carcinogen contamination, especially the advances in biosensing methods. Furthermore, the application of promising technology including nanomaterials, imprinted polymers, and microdevices is detailed. Challenges and perspectives are also discussed.
    Analytical and Bioanalytical Chemistry 02/2015; 407(10). DOI:10.1007/s00216-015-8530-8 · 3.58 Impact Factor