The Preparation Of Two-dimensional Quantum Dots And Its Application In Electrochemiluminescence Sensing

Two-dimensional quantum dots?2D-QDs?are widely used in the field of photocatalysis,energy storage and conversion,lithium batteries,and biomedicine because of their unique quantum size effect and photochemical properties.Among them,graphene quantum dots?GQDs?,molybdenum disulfide quantum dots?Mo S₂QDs?,graphite carbon nitride quantum dots?g-C₃N₄ QDs?,etc.have clear structures,rich edge sites and functional groups,which can provide new technical support for early cancer diagnosis environmental monitoring.In this paper,three different2D-QDs have been synthesized,of which the ECL properties and related mechanisms are investigated to lay a theoretical foundation for the subsequent ECL sensor architecture.Based on signal amplification technology,we are committed to constructing ECL sensors with high sensitivity and strong selectivity to achieve rapid diagnosis of target.The details are as follows:1.Electrochemical luminescence sensor based on the signal probe Mo S₂quantum dots for ultra-sensitive detection of He La cells:The luminescent material Mo S₂ QDs with good water solubility was synthesized by hydrothermal method.Based on the excellent ECL performance of Mo S₂ QDs,ECL signal amplification function of Ti₃C₂ nanosheets,GO and Au NPs,and specific binding between folic acid?FA?and the expressed folate receptor?FR?of He La cells,an ECL cell sensor Au NPs/Mo S₂QDs-PEI-GO@FA has been designed.The experimental results showed that the sensor had a wide detection range?1.0×10²?5.0×10⁷cells/m L?,higher sensitivity,and lower detection limit?17 cells/m L,S/N=3?,which could be used to detect He La cervical cancer cells.2.Bi₂S₃ nanoparticles-based self-enhanced ECL immunosensor for ultra-sensitive detection of cyclin D1:Bi₂S₃ NPs with monodisperse,good colloidal stability and biocompatibility were synthesized by BSA-mediated biomineralization.For the first time,the ECL properties and related theories of Bi₂S₃ NPs were explored,including annihilation ECL and co-reactant enhanced ECL.It was found that in the presence of co-reactant K₂S₂O₈,the cathode ECL emission of Bi₂S₃ NPs was significantly enhanced?about 20 times?.Inspired by the above,Bi₂S₃ NPs was used as ECL luminescent reagents to construct ECL immunosensors to detect cyclin D1?CCND1?.A composite material of Au@Cu-Bi₂S₃NPs was synthesized by using Cu²⁺as an ion bridge to connect Bi₂S₃ NPs and Au NPs through chelation of metal ions.The conductivity of Cu²⁺and the surface plasmon resonance of Au NP make the ECL signal amplified again.In addition,PDA-Ag NPs not only increase the conductivity of the electrode and can also be used as a platform for fixing the primary antibody?Ab₁?.The analysis results show that the sensor has lower detection?6.34 fg/m L?,wider detection range?10 fg/m L?1?g/m L?,good stability and reliable reproducibility compared with the previously reported work.3.Research on high sensitive ECL sensor based on Ag-N-Ti₃C₂ quantum dots:Monodispersed Ti₃C₂ QDs and nitrogen-doped titanium carbide quantum dots?N-Ti₃C₂ QDs?with good optical properties were synthesized by hydrothermal method,respectively,and then the ECL behavior and related mechanisms of these two quantum dots were investigated and compared.Next,a highly sensitive ECL sensor based on Ag-N-Ti₃C₂QDs was firstly built to detect S^2-.The prepared Ag-N-Ti₃C₂QDs composite material greatly improves the ECL intensity of the sensor,and Polypyrrole?PPy?conductive hydrogel was applied to further improve the sensitivity of the sensor.The results showed that the ECL intensity of the sensor had a good linear relationship with S^2-,a low detection line and high specificity.Therefore,this method can be further applied to more environmental case studies.