Preparation Of Immunochromatographic Strip Based On Aggregation-Induced Luminescence Nanobeads For The Chloramphenicol,Procalcitonin And Zearalenone Detection

Immunochromatographic assays have been widely used in food safety,environmental monitoring and clinical diagnosis because of their unique advantages,including simplicity,rapidity,user-friendliness and low cost.However,the coventional colloidal gold based strip always suffers from the low detection sensitivity due to its weak brightness,and thereby,cannot meet the requirements for the target detection with trace concentration.Compared with the absorbent labeling material,the fluorescent labeling materials have better optical properties and higher detection sensitivity.Currently,the commonly used luminescent materials mainly include organic dye fluorescent microspheres,quantum dot beads,time-resolved fluorescent microspheres,up-conversion fluorescent nanoparticles,and so on.However,the above fluorescent materials are always restricted by their ACQ effect in a high concentration or aggregation state,and resulting in a reduced luminous efficiency.Aggregation-induced emission（AIE）dyes have the characteristics of aggregation-induced luminescence with a larger Stokes shift and better photobleaching resistance.In theory,AIE dyes are considered as the most ideal embedding material to prepare the highly luminescent labeling materials.In this study,a novel fluorescent strip with competitive format was established for the chloramphenicol detection in real fish samples by using an AIENPs with green fluorescence emission as signal labels.The proposed AIENPs-ICA exhibited a good dynamic linearity for the chloramphenicol quantitative detection with the chloramphenicol concentation ranging from 16 pg m L^-1to 0.5 ng m L^-1with the IC₅₀and LOD values at 69 pg m L^-1 and 10 pg m L^-1,respectively.The average recoveries of intra-and inter-assays for detecting chloramphenicol fortified fish samples were in a range of 86.39%～118.96%with the coefficient of variation less than 13.64%,indicating that the AIENPs-ICA has an accepted accuracy and precision for the quantitative determination of CAP in real fish samples.All in all,the AIENPs was confirmed an ideal novel fluorescent labeling material for enhancing the detection performance of ICA.Secondly,the luminescent property and colloid stability of AIENPs were further compared with those of conventional fluorescein isothiocyanate nanoparticles（FITCNPs）,where the FITCNPs was one of the most widely used organic fluorescein dye-embedded nanoparticles.The average diameters of AIENPs and FITCNPs were350 and 450 nm,respectively.At the same mass concentration,the fluorescence intensity of AIENPs was eight times higher than that of FITCNPs,while the Stokes shift of AIENPs was also four times larger than that of FITCNPs.These two FMs were used as the labeling markers of ICA for procalcitonin（PCT）detection with the sandwich format.Among them,AIENPs-ICA showed dynamic linear detection of PCT from 7.6 pg m L^-1 to 125 ng m L^-1 with the limit of detection（LOD）at 3.8 pg m L^-1.These values were remarkably superior to those of FITCNPs-ICA(linear range from 61 pg m L^-1 to 62.5 ng m L^-1 and LOD value at 60 pg m L^-1).Furthermore,the average recoveries of the intra-and inter-assays of AIENPs-ICA ranged from 86%to112%,with coefficients of variation ranging from 1.2%to 8.8%,indicating accuracy and precision for PCT quantitative detection.Additionally,the reliability of the developed AIENPs-ICA was further assessed by analyzing 30 real serum samples from systemic inflammatory response by infectious diseases,and the results showed good agreement with the chemiluminescence immunoassay.In conclusion,compared with traditional FITCNPs,green emitted AIENPs as a novel fluorescent label,exhibits greater potential to enhance the detection performance of the ICA platform.In addition,the metal-polyphenol network structure（MPN）was uses as a coating material of AIENPs for improving optical properties and coupling efficiency,in which the AIENPs was prepared by the microemulsion method.The MPN was prepared by mixing the different metal ions and tannic acid（TA）solution,and the Zr⁴⁺-TA based MPN shows the better structural stability as network coatings of AIENPs in extremely acidic aqueous solution（p H=3）,and the Zr⁴⁺-TA network coating can also improve the anti-photobleaching of AIENPs.Then,the fluorescent probe(AIENP_MPN@ZEN m Abs)was prepared by labeling the antibodies on the surface of AIENPs via the electrostatic adsorption method,and the antibody were completely attached on the surface of AIENPs within 15 min incubation time.The as-prepared AIENP_MPN@ZEN m Abs was further used to develop a competitive immunochromatography strip for the detection of zearalenone（ZEN）.Under the optimized conditions,the developed AIENP_MPN-ICA showed a high sensitivity for ZEN determination in real corn sample with a LOD at 3 pg m L^-1,which is far superior to that of previous report.In conclusion,this study provides a new strategy for preparing a high-performance AIENPs probes via metallic polyphenol network coating,and provides a new idea for preparing labeled probes by integrating polyphenol substrate and inorganic materials.