Construction Of Electrochemiluminescence Sensor Based On Metal Nanomaterials And Its Application In Biological Detection

Electrochemiluminescence（ECL）has great selectivity and high sensitivity.Traditional organic light emitters have the disadvantages of low luminous intensity and easy quenching,which makes it difficult to achieve high-sensitivity detection of biomolecules.Thus,the development of efficient and stable ECL emitters has always been one of the research hotspots of ECL field.Metal nanoclusters have good biocompatibility and unique optical properties,which provides new ideas for the synthesis of emitters and the construction of biosensors.Biomarkers（such as thrombin,dopamine,etc.）are closely related to some human diseases,so the detection of biomarkers is of great significance for the early diagnosis and treatment of diseases.Aiming at the problems of expensive early detection methods,complicated operation,low sensitivity and selectivity,this paper designs ECL biosensors based on metal nanoclusters to overcome the shortcomings of poor sensitivity and selectivity of traditional detection technologies and uses them for highly sensitive detection of biomarkers.The main work is as follows:（1）Green synthesis of Pd nanocones as a novel and effective electrochemiluminescence illuminant for highly sensitive detection of dopamineHerein,well-defined Pd nanocones（Pd NCs）were facilely obtained by a one-pot hydrothermal method with poly-L-lysine（PLL）as a green protecting ligand,which were first explored as an anodic ECL emitter,where tripropylamine（TPA）worked as the coreactant to fabricate Pd NCs/TPA system.The possible ECL mechanism of Pd NCs/TPA system was extensively explored by ECL and electrochemical techniques.Briefly,Pd NCs and TPA were initially oxidized,and then the oxidized TPA lost a proton to form reducing agent（TPA·）strongly reacted with the oxidized Pd NCs generating Pd NCs*for the emission.The ECL radiation of the Pd NCs/TPA system was quenched based on the electron transport blocking effect of dopamine（DA）,and then an ultrasensitive sensor was constructed for DA detection.The fabricated sensor shows good stability,and wide linear range with the low detection limit of 0.46 pM.（2）Construction of aptasensor for thrombin detection using palladium nanocones boosted electrochemiluminescence systemA label-free aptamer biosensor for ultrasensitive thrombin（TB）detection was constructed based on functional Pd NCs with tripropylamine（TPA）system.Herein,well-defined Pd NCs were initially functionalized by MCH as an ECL emitter and immobilized onto the GCE initially grafted with amine-terminated polyamidoamine（PAMAM）via electro-oxidation reaction.Under optimal incubation time and pH,the ECL intensity of the Pd NCs/TPA system was about 2.5 times enhancement.The ECL and cyclic voltammetry（CV）were synchronously employed to illustrate the enhanced ECL mechanism.After functionalized Pd NCs were combined with thiolated TB aptamer（TBA）and bovine serum albumin（BSA）blocked non-specific sites,a label-free ECL bioassay platform was designed.The ultra-sensitive detection of TB can be realized utilizing the steric hindrance effect with lower detection limit（even down to 6.76 fM）and good selectivity and stability.（3）Synthesis of flower-like metal-organic frameworks and ultrasensitive detection of breast cancer 1 geneThe ECL organic emitter of carboxyl-rich tris（4,4′-dicarboxylic acid-2,2′-bipyridyl）ruthenium（II）(Ru（dcbpy）₃²⁺)was utilized to chelate Zn ion for forming the high-performance metal-organic frameworks microsphere flowers materials（ZnMOF（Ru））from order accumulation with the cetyltrimethylammonium bromide（CTAB）as structure-directing agent.By comparison,the ECL intensity of ZnMOF（Ru）enhanced about 53-fold than that of Ru（dcbpy）₃²⁺at the same equivalent concentration without any coreactants due to the organic molecular framework aggregation effect.Based on this,a―sandwich‖model ECL biosensor was designed for breast cancer gene detection ranging from 1 fM to 0.1 nM with an unltr-low limit of 0.71 fM.This work provides a universal and robust pattern to exploit the ECL nano-luminophore and expands the application potential of MOF materials in bioanalysis fields.