Application Of Lanthanide Metal Materials In Electrochemiluminescence Biosensors

Electrochemiluminescence（ECL）,also known as electrogenerated chemiluminescence,is generated by the chemical reaction of electrically induced free radicals to produce excited state and return to the ground states.ECL is a detection method that combines the advantages of electrochemistry and spectroscopy.Due to its advantages of high sensitivity,fast response,simple setting and operation,low cost and small instrument,it has attracted wide attention.Therefore,biosensors based on ECL for virus detection and pollutant detection have become one of the fastest growing sensors in this field.Lanthanide elements are one of the important elements in the periodic table.Due to its large atomic radius and 4f electron properties,lanthanide is widely used in imaging,medicine and magnets.Lanthanide metal materials exhibit many properties in optics,conductivity,biocompatibility and catalysis.Lanthanide metal materials are introduced into the ECL sensor to improve the sensitivity and multiple possibilities of the sensing area.According to the constructed sensor,various disease markers can be detected efficiently and accurately,providing basis for early diagnosis and treatment of diseases.This paper has the following three parts:（1）The luminol-based chemiluminescence immunosensor based on multiple oxidation states of bimetallic oxides Co Ce Ox and Ni Mn O₃ was amplified for the detection of CYFRA21-1.Bimetallic oxides are concerned because of their variety of oxidation states and their better electrochemical performance than mono-metallic oxides.In this work,Au NPs with excellent electrochemical properties were modified on the surface of bimetallic oxide Co Ce Ox with large specific surface area and then L-Cys was grafted.The synthesized Co Ce Ox@Au@L-Cys was fixed on the surface of GCE as a sensing platform.The layered flower-like bimetallic oxide Ni Mn O₃ was prepared by template-free hydrothermal method.The bimetallic Ni Mn O₃ has adjustable morphology and redox chemical properties.The synergistic interface effect between Mn and Ni components can also improve the catalytic performance of Ni Mn O₃ composite.Using Ni Mn O₃@Au-luminol-Ab₂ as a signal indicator,ECL biosensor was successfully constructed for accurate and efficient detection of CYFRA21-1.The detection range is 0.001–150 ng/m L,and the detection limit is 0.3 pg/m L.（2）Gold-modified spindle-shaped Ce PO₄ is used as an efficient co-reaction accelerator to amplify the electrochemiluminescence signal of carbon quantum dots for the ultra-sensitive analysis of AFB1.Hexagonal cerium phosphate was synthesized by hydrothermal method using the high affinity of phosphate group to lanthanide ions.The repeated conversion of Ce³⁺and Ce⁴⁺has high catalytic activity and electrical activity,which can promote the production of O₂^·-.Ce PO₄@Au can promote the decomposition of H₂O₂ to produce O₂^·-.Cerium phosphate modified with gold was determined as the substrate of biosensor through experimental research.Ba Ti O₃ with stability and usability was selected as the nano-carrier,and Ag NPs were modified on its surface to enhance conductivity and load NHCDs as signal markers to accurately capture Ab₂,and a sandwich immunosensor was constructed for the detection of AFB1.The constructed sensor has good linearity for AFB1 detection in the range of 0.01 pg/m L–100 ng/m L,and the detection limit is 9.55 fg/m L.（3）Ce PO₄/Ce O₂ heterostructure and D-Fe₂O₃ enzymolysis co-amplify luminol-based electrochemical luminescence immunosensor for the detection of NSE.In this work,Ce PO₄/Ce O₂ heterostructure with a large number of Ce⁴⁺/Ce³⁺redox pairs was synthesized by stirring method.Au NPs improved the conductivity of the material and continued to connect-NH₂ to capture Ab₁ through the amide bond.Ce PO₄/Ce O₂@Au-NH₂ was fixed on the surface of the glassy carbon electrode as a coreaction catalyst.D-Fe₂O₃ nanoenzyme with peroxidase-like activity was synthesized by hydrothermal method.Using luminol@D-Fe₂O₃@Pt-Ab₂ as a signaling probe,the decomposition of H₂O₂ is catalyzed to produce·OH through the peroxidase activity of D-Fe₂O₃@Pt.Based on the double signal amplification of the substrate and signal probe,a stable and efficient sandwich immunosensor was established for the ultra-sensitive detection of NSE.The developed biosensor has a detection range of 76 fg/m L-100 ng/m L with a detection limit of 72.4 fg/mL.