Development Of Persistent Luminescent Signal Transduction Systems For Analytical Application

Luminescent signal transduction systems have the advantages of high selectivity and sensitivity,simplicity and rapidness,and flexible design.Persistent luminescent signals have the merits of good repeatability and little interference from sample matrix for promising applications in the field of complex sample analysis.In this dissertation,several glow-type chemiluminescence and long-afterglow signal transduction systems have been developed for the determination of trace analytes in food and biological samples with high sensitivity and good selectivity.The main research results are as follows:An enhanced bienzymatic chemiluminescence competitive immunoassay was developed for ultrasensitive and high-throughput determination of AFB₁.Protein G was first coated on the wells of the microplate to recognize the Fc fragment of anti-AFB₁ monoclonal antibodies?anti-AFB₁ mAbs?so as to reduce the antibody dosage and guarantee high immunological reaction efficiency.The glucose oxidase conjugated AFB₁?AFB₁-GOD?was prepared to compete target AFB₁ for binding the limited anti-AFB₁ mAbs in the wells of the microplate.The utilization of p-bromophenol as an enhancer along with GOD and horseradish peroxidase?HRP?as high efficient bienzymatic catalysts resulted in stable and enhanced chemiluminescence,which significantly improved the detection sensitivity and broadened the linear range of detection.The developed method offered a good linearity over 5 orders of magnitude,a detection limit of 5 pg L^-1 and good selectivity.The precision of the developed method was 1.9%?RSD,n=11?for AFB₁ at 100 ng L^-1.The developed method was successfully applied to the determination of AFB₁ in grain samples with quantitative recoveries from 94.0%to 97.0%.The proposed assay provides a universal platform for high-throughput,ultrasensitive,and high specific detection of pollutants or nutrients in foods.A dual-signaling nanoplatform for the ratiometric absorption and time-resolved luminescence resonance energy transfer was developed based on L-cysteine-mediated aggregated gold nanoparticles?AuNPs?and persistent luminescence nanoparticles?PLNPs?.The high molar extinction coefficient and tunable absorption of AuNPs,and L-cysteine-mediated aggregation of AuNPs enabled significant red shift in the absorption peak,providing a ratiometric signal for the detection of L-cysteine.The energy transfer between long afterglow emission of PLNPs and absorbance of L-cysteine-mediated aggregated gold nanoparticles provides a platform for insulin determination.This dual signal transduction system offered high-throughput sequential detection of L-cysteine and insulin.The proposed nanoplatform showed excellent linearity and precision for the determination of L-cysteine in the range of 10 nmol L^-1 to 5.5?mol L^-1 with the limit of detection?LOD?of 2.2nmol L^-1,and for the detection of insulin in the range of 12 pmol L^-1 to 3.4 nmol L^-1 with LOD of 2.1 pmol L^-1.The developed dual-signaling nanoplatform has been successfully applied for the sequential determination of L-cysteine and insulin in human serum without matrix interference.Torpedo-shaped green luminescent long afterglow nanoparticles(Zn₂GeO₄:Mn²⁺,Pr³⁺)?ZGMP?with regular morphology,uniform particle size and good luminescent performance were prepared by one-step hydrothermal synthesis method.The prepared ZGMP exhibited excellent acid stimulus-response luminescent behavior.The possible mechanism for the acid stimulus-response was also discussed.The features of persistent luminescence and acid responsiveness of ZGMP was explored to integrate enzyme catalysis reaction mediated p H modulation for selective determination of glucose in serum and AFB₁ in grains.The acid stimulus-responsive ZGMP has good analytical performance for promising application in food safety and bioanalysis.