Construction Of Nanocomposite Based ECL Sensor And Its Application In Cancer Marker Detection

Electrocheluminescence（ECL）is a method of converting electrical energy into radiant energy.It involves the production of active intermediates from stable precursors on the surface of an electrode.These intermediates are reacted under various conditions to produce the excited state of luminescence,which then returns to the ground state and luminescence occurs.This technique has been widely studied by more and more researchers due to its excellent features such as near-zero background,excellent sensitivity,fast response time and wide dynamic range.In this paper,we investigated the novel self-reinforced hollow double-shell nanospheres Ce O₂@g-C₃N₄andCe O₂/Pt/r GOwithNH₂-Si O₂-PTCAnanocompositesfor electrochemiluminescence system,and constructed electrochemiluminescence immunosensors for the sensitive detection of pancreatic cancer marker antigen（CA19-9）and breast cancer marker antigen（CA15-3）successfully.The results were satisfactory.The specific work of this thesis is as follows:Chapter 1:Introduction mainly reviews the concept of electrochemiluminescence,luminescence mechanism,commonly used nanoluminescents,major nano-co-reaction accelerators,and analytical applications of electrochemiluminescence.Chapter 2:Ce O₂@g-C₃N₄double-shelled hollow spheres were skillfully synthesized as a novel type self-enhanced electrochemiluminescent（ECL）emitter by a highly efficient outside-in hard template method.Thanks to its great catalytic ability,Ce O₂were served as a co-reaction accelerator for improving ECL performance of the hollow g-C₃N₄spheres（HCNSs）/S₂O₈^2-system.In addition,the self-enhanced ECL emitter is designed as a complex containing a co-reaction accelerator and a luminophore to shorten the electron transfer path,which decreases the energy loss of the luminophore significantly.More importantly,the unique double-shelled hollow structure not only greatly decreases the inner filtering effect,but also maximizes the utilization efficiency of the ECL luminophores by increasing a Ce O₂shell inside the HCNSs as co-reaction accelerator,effectively enhancing the ECL intensity.Under the optimal conditions,the designed ECL immunosensor showed excellent performance in the determination of CA19-9 with a linear range of 0.50 m U m L^-1-500.00 U m L^-1and a low detection limit of 0.039 m U m L^-1.Importantly,the resulting biosensor has good stability,high sensitivity and reliable reproducibility,suggesting its potential application in clinical research.Chapter 3:This chapter focuses on the preparation of Ce O₂/Pt/r GO nanocomposite and its first application as a co-reaction accelerator in an ECL system.Compared with pure Ce O₂nanomaterials as a co-reaction accelerator,on the one hand the composite improves the catalytic performance of the material due to the Pt nanoparticles that effectively enhance the electrical conductivity of Ce O₂.On the other hand,the addition of r GO nanosheets cleverly avoids the excessive agglomeration of Ce O₂material,improves the dispersion ability of Ce O₂,increases the catalytic surface area,which effectively enhances the catalytic activity and stability of the material.Thus,it effectively accelerates the generation of radical anions and greatly improves the luminescence intensity of the luminescent clusters.In addition,perylene-organic-3,4,9,10-perylenetetracarboxylic acid（PTCA）was attached to the surface of silica nanospheres（NH₂-Si O₂-PTCA）via a silane coupling agent as the luminescent of the ECL system.Since PTCA has the characteristic of anti-induced luminescence,attaching PTCA to silica nanospheres can effectively reduce the anti-induced luminescence and thus improve the luminescence intensity.Under the optimal conditions,the designed ECL immunosensor exhibited extraordinary performance in the determination of CA15-3 with a linear range of 12.00 m U m L^-1-120.00 U m L^-1and a detection limit of 0.362 m U m L^-1.In addition,the constructed ECL sensor exhibited excellent stability,precise selectivity and a wide In addition,the constructed ECL sensor showed excellent stability,precise selectivity and wide linearity range,indicating its potential medical application.It also provides an alternative route for sensitive detection of cancer marker antigens.