The Construction Of Ultra-sensitive ECL Platform Based On Magnetic MOFs And Its Application In Enrichment And Detection Of Cancer Markers

Electrochemiluminescence(ECL)is a novel detection technology which combining electrochemical and chemiluminescence,has been widely studied in recent years because of its low background signal,high sensitivity and operational controllability.However,due to the instability in the detection of adopting single ECL method for simple labeling has limited the practical application of ECL technology.Therefore,it is necessary to introduce some new materials with good properties into the ECL field,which will tap the application potential of ECL technology.In this work,a new luminescent material with superior ECL performance was prepared,which will be immobilized by the combination of MOFs and magnetic beads(MB)so that the final nanoprobe could be highly magnetic enriched in detection process,which realized the construction of a new ECL sensing platform.In addition,in order to further improve the detection accuracy,a ratio detection platform based on magnetic highly efficient enrichment has been successfully constructed which will achieve the highly sensitive detection of cancer markers(AFP,PSA).The main works are as follows:Chapter 1:This chapter focuses on the luminescence mechanism,historical origin and practical application of ECL,and summarized the advantages and disadvantages of different types of luminophore in various strategies and fields.Meanwhile,we provided an outlook of the promising application of ECL through continuous research and exploration.Chapter 2:In this chapter,an original magnetic ECL platform with remarkable electrochemiluminescence(ECL)performance was proposed which based on the co-growth of the CdSnS nanocrystallines(NCs)and UiO-66-NH2 on the surface of the magnetic metal-organic framework(MMOF).Herein,the carboxyl groups(-COOH)CdSnS NCs participated in the further growth of MMOF and formed octahedron-shaped MMOF@CdSnS nanoparticles,this strategy prevented the aggregation of CdSnS NCs and resulted in an excellent ECL emission intensity,which could be applied as the promising ECL tag.Besides,the MMOF@CdSnS nanoparticles exhibited superior superparamagnetism that achieved outstanding performance in magnetic enrichment,which could be magnetic enriched by the functional magnetic(FM-ITO).Due to these advantages,the proposed ECL platform was applied in detecting alpha-fetoprotein(AFP)as an example.Under optimized conditions,the ECL response was decreased as the concentration of AFP increased that followed a good linear relationship from 1 fg mL-1 to 100 ng mL-1 with an ultra-low detection limit of 0.2 fg mL-1(S/N=3).With favorable sensitivity,specificity and reproducibility,the MMOF@CdSnS nanoparticle was firstly introduced in ECL bioanalysis,which broadened the applications of MMOF and created a new method in enhancing the ECL intensity.This work demonstrated the strategy that MMOF-immobilized CdSnS NCs nanocomposite which was further magnetic enriched shed light on new way in ECL detection.Chapter 3:In this chapter,a ratio magnetic electrochemical(ECL)sensing platform was constructed which based on using magnetic metal-organic framework(MMOF)and UiO-66-COOH as carriers to load CdSnS nanocrystals(NCs)and luminol respectively for the detect of cancer markers(PSA as a model).The CdSnS NCs and luminol were loaded with MMOF and UiO-66-COOH to avoid the aggregation,which could guarantee the excellent ECL performance of MMOF@CdSnS and UiO-66-COOH@luminol.Subsequently the two antibodies(Ab1 and Ab2)were incubated respectively to form MMOF@CdSnS@Ab1 and UiO-66-COOH@luminol@Ab2.Then the two ECL material would combine in the presence of specific antigen and formed MMOF@CdSnS@Ab1-Ag-UiO-66-COOH@luminol@Ab2 dual-ECL signal composites,which would magnetic enrich by functional magnetic(FM-ITO).As the antigen concentration was increased,the combination of two composites was also increased which lead to the more enrichments of UiO-66-COOH@luminol@Ab2 on FM-ITO and enhanced the anode ECL intensity.Meanwhile,with the cathode ECL intensity is basically unchanged,the accurate detection of cancer markers would be acquired by the ratio of cathode and anode ECL intensity.Under optimized conditions,a good linear relationship from 1 fg mL-1 to 50 ng mL-1 with an ultra-low detection limit of 0.17 fg mL-1(S/N=3)was acquired.With favorable sensitivity,specificity and reproducibility,the magnetic ratio ECL detection platform provides a new strategy for the practical applications of ECL.