Study On The Mechanism And Application Of Novel Chemiluminescence/electrochemil-Uminescence Systems

Chemiluminescence(CL)and electrochemiluminescence(ECL)have been widely used in modern analysis and detection due to the advantages of low background signal,simple instrument operation,and wide signal response window.Now,the rapid development of various fields puts forward higher requirements on the sensitivity of analytical methods and analytical instruments.However,the construction of highly sensitive CL/ECL sensors still faces some challenges:(1)The loading rate and luminous efficiency of classical CL/ECL emitters(such as ruthenium bipyridine)in nanomaterials are low;(2)The scarcity of high-efficiency CL/ECL emitters limits the sensing application of CL/ECL.Considering above issues,this thesis mainly focuses on the development of new strategies to improve the CL/ECL efficiency of classic emitters and the development of new CL/ECL reagents with high quantum yield and special properties as follows:1.Utilizing the strong coordination between carboxyl-rich tris(4,4’-dicarboxylic acid-2,2’-bipyridyl)ruthenium(Ⅱ)(Ru(dcbpy)32+)and Zn2+,a two-dimensional metal organic framework nanosheet(RuMOFNSs)with high ECL efficiency was synthesized.We covalently coupled the antibody to the surface of RuMOFNSs and used it as a signal probe to construct an immunosensor to achieve the sensitive detection of cardiac troponin I(cTn1).In this work,directly immobilizing the luminescent molecules as bridging ligands in rigid MOF increased the loading rate of the ECL emitters,and the effective enrichment of the coreactant by the MOF micropores shortened the electron transfer distance between the coreactant and the emitters,then the ECL efficiency was improved.2.Self-enhanced CL nanoparticles(BRuNPs)were prepared by covalent bonding Ru(dcbpy)32+with branched polyethylenimine(BPEI),which were oxidized by potassium peroxodisulfate(K2S2O8)and then produced strong and stable CL emission through intermolecular and intramolecular electron transfer processes.In this system,both K2S2O8 and BPEI are the coreactants of Ru(dcbpy)32+.This covalent coupling method simplifies the reaction steps and partially shortens the distance of electron transfer,so the CL intensity was self-enhanced.Ag+can catalyze the decomposition of K2S2O8 to enhance CL intensity,we used Ag+as a coreaction accelerator of BRuNPs/K2S2O8 system to design a ternary high-efficiency selfenhanced CL system,and indirectly realized the sensitive detection of Ag+.This work is of great significance to the development of a new type of self-enhanced CL probe.3.We used a coumarin derivative(C545T)with photoluminescence efficiency near to 100%as a candidate material for ECL,and systematically studied its electrochemical,photophysical,and ECL properties.C545T can generate obvious annihilation ECL signals in organic phase.The C545T microrods(C545T MRs)with good dispersibility were synthesized by reprecipitation method,which also showed excellent ECL performance in aqueous phase.When triethanolamine is used as coreactant,it shows the highest luminous efficiency,which is 81%of Ru(bpy)32+/TEOA system under the same conditions.Based on the quenching effect of dopamine(DA)on the ECL of C545T MRs/TEOA system,the high selectivity and sensitivity detection of DA was realized.4.An efficient solid-phase ECL system was developed based on the aggregation-induced electrochemiluminescence(AIECL)of a stilbene derivative(DPVBi).As the aggregation degree increases,the non-radiative relaxation caused by the intramolecular motion of DPVBi is suppressed,so the ECL emission intensity is significantly enhanced.The DPVBi nanobulks(DPVBi NBs)were prepared by nanoprecipitation method,which was modified on the electrode surface to fabricate a sensing platform.When triethylamine(TEA)is used as the coreactant,the ECL efficiency of DPVBi NBs is significantly higher than that of the classic AIECL systems based on tetraphenylethylene and its derivatives.With the help of the electrodeposited gold nanoparticles,a label-free immunosensor was developed and the sensitive detection of cTnI was realized.This organic nanomaterial with AIECL characteristics enriches the ECL systems and provides a direction for the development of new ECL functionalized nanomaterials for biosensing.