A Novel Aptamer-based Suspension Array Technology For The Ultrasesitive Detection Of Endocrine Disrupting Chemicals

Human are facing with a growing number of serious environmental pollution and foodborne illness,which has become the hot spots of social concerning.Among of them,a variety of endocrine disrupting chemicals?endocrine disrupting chemicals,EDCs?have been paid more and more attention all over the world.EDCs commonly exist in environment,with good chemical stability and hard to decompose in vitro and in vivo.These substances are accumulated easily in human body by food chain,which possibly has much lasting harmful impact on human.Its severity is even risen to the height of the survival of the country and the nation.These chemicals can interfere with normal endocrine function,causing a range of reproductive and developmental disorders,metabolic disorders,and even result in tumors.There are both advantages and disadvantages to normal technique of on-site detection and laboratory detection technologies.However,the techniques can not satisfy requirements of high-through put,rapid and sensitive detection.Suspension array technology platform has been established for a variety of agricultural and veterinary drug residues in the early stage of our group.The technology is high-throughput,however,antibody of small molecule is expensive,and the sensitivity and specificity are not stable and need to be improved.It is particularly important that high specificity and sensitivity detection platform should be established.The work is focused on typical EDCs such as17-?-Estradiol?E₂?and Bisphenol A?BPA?,etc.Based on the advantages of carbon nanomaterials,such as large surface area,controllable physisorption with biomaterials,the novel aptamer-suspension array for the detection of multiple EDCs has been established.The single-walled nanotubes?SWNTs?were modified by amino groups based on the ethylenediamine condensation agent,the structure was characterized by FT-IR,and XPS,respectively.And the rate of amino-modification is 2.46%.Amination of SWNTs was modified on the surface of magnetic beads?MBs?.And the specific surface of MBs was enlarged and the signal was amplified,too.Fluorescent reporter protein,i.e.streptavidin R–phycoerythrin?SA-PE?was coupled with biotinylated aptamer of BPA and E₂ via avidin-biotin mechanism.The combination of all three formed the probe beads.The existence of BPA and E₂ caused changes of the three-dimensional conformation of aptmer.The complexes were slipped from probe beads.Then the median fluorescence intensity?MFI?was correspondingly decreased by suspension array.The concentrations of BPA and E₂ in the samples could be examined.The optimum interaction conditions and coupling protocol were optimized,such as the quantity of SWNT and SA-PE,incubation time and temperature,etc.Under the best conditions,the standard curves for the detection of BPA and E₂ were plotted.The dynamic quantitative working range of BPA was 0.3472-59623.7742pg/mL(IC₁₀-IC₉₀),and the lowest detection limit?LDL?was 0.3472 pg/mL.The dynamic quantitative working range of E₂ was 0.5575-1928.3663pg/mL,and the LDL was 0.5575pg/mL,respectively.It suggested that the detection technology had a wider detection range and higher sensitivity.The method had distinct advantages comparing with standard suspension array technology and the classical ELISA.The specific test demonstrated the good specificity of the novel detection technology.BPA and E₂ were added in Haihe River samples to determine the recovery.The recoveries of the spiked BPA and E₂ were 80% to 120% with relative standard deviations?RSDs?below 10%,thus the result was satisfied.We firstly combined the carbon nanomaterials,aptamer and suspension array technology to establish a novel detection technology with the integration of methodological and technological innovation.The method can achieve ultrasensitive,specific detection of various EDCs,provides technical and theoretical support for rapid detection of a variety of chemical contaminants.It may be applied in the fields of food hygiene,hygienic inspection and environmental monitoring with theoretical significances and practical values.