Design Of Fluorescence Probe Based On MoS₂ Quantum Dots For Biosensing Research

As a graphene-like structural material,molybdenum disulfide is used in batteries,catalysts,and transistors.However,few reports have been published on the optical properties,especially the application of photoluminescence to analytical chemistry.The molybdenum disulfide quantum dots?MoS2 QD?with fluorescent properties have excellent performance in cell imaging and chemical sensing applications.In order to further improve the fluorescence performance and expand the application range of MoS2 QDs,surface functionalization is usually a very efficient way.In this study,a simple bottom-up method,the hydrothermal method,was proposed to synthesize photoluminescence MoS2 quantum dots.The prepared MoS2 quantum dots were characterized by transmission electron microscopy,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy,fluorescence spectroscopy and UV-visible spectroscopy.Then,different MoS2 quantum dots were used as photoluminescence probes to construct a fluorescence sensor for detecting heavy metal ions,organophosphorus pesticides and antibiotics.The sensor has high selectivity,strong sensitivity and low detection limit.It is used in the detection of actual samples and has potential application value.The molybdenum disulfide quantum dots?MoS2 QDs?were synthesized by hydrothermal method using molybdate sodium as molybdenum source and L-cysteine as sulfur source and stabilizer.UV-Vis,fluorescence and IR spectra were used.The structure and properties of quantum dots were characterized.The molybdenum disulfide quantum dots exhibit strong blue fluorescence properties and have good dispersibility.MoS2 quantum dots were then used as fluorescent probes to construct a fluorescence annihilation sensor for detecting Hg2+.The linear range of the method for the determination of Hg2+ is 0.5-200 ?mol/L,the detection limit is 23 ?mol/L,and the correlation coefficient is 0.998.The effect of molybdenum disulfide quantum dot probe and Hg2+ on fluorescence quenching phenomenon,which established a new method for the determination of Hg2+ fluorescence analysis.The method has the characteristics of simple operation,high sensitivity and good selectivity,and can be used for the determination of trace Hg2+ in tap water samples.A bottom-up strategy was developed to synthesize water-soluble molybdenum disulfide quantum dots?MoS2 quantum dots?in a simple,one-step hydrothermal process using?NH4?2MoS₄ tetrathiomolybdate?NH4?2MoS₄.)For the precursor,ethylene glycol is a reducing agent.Synthesized MoS2 quantum dots have a small size distribution with an average diameter of about 5 nm.A novel organophosphorus pesticide nanosensor based on fluorescence resonance energy transfer?FRET?of MoS2 quantum dots was designed.The detection mechanism is based on the fluorescence of MoS2 quantum dots annihilated by gold nanoparticles?AuNPs?,the inhibition of acetylcholinesterase?AChE?activity by organophosphorus pesticides?OPs?,and the inhibition of the hydrolysis of acetylcholine?ATC?into choline The fluorescence intensity of the system changes to achieve the detection of organic phosphorus.Under the optimal detection conditions,the concentration of organophosphorus pesticides is proportional to the inhibition efficiency.The linear range of determination of organophosphorus pesticide-methyl paraoxon was 1-100 ?mol/L,and the detection limit was 0.81 ?mol/L.At the same time,the biosensor has good sensitivity and stability and is expected to be applied to the detection of OPs in actual samples,indicating that the biosensor has a wide range of application detection capabilities.The molybdenum disulfide quantum dots?MoS2 QDs?were prepared by hydrothermal method.The precursors were ammonium tetrathiomolybdate??NH4?2MoS₄?and ethylenediamine was used as the reducing agent to synthesize the molybdenum disulfide quantum with blue fluorescence.Points and use it for the detection of antibiotics.Using oxytetracycline to quench the fluorescence of molybdenum disulfide QDs,a rapid,simple and reliable fluorescent probe detection method was developed.Under the optimum conditions,the linear relationship between the fluorescence intensity of molybdenum disulfide quantum dots and antibiotics was linear,the linear range was 1-60 ?g/mL,the detection limit was 0.226 ?g/mL,and the correlation coefficient was 0.996.This method is to be used for the determination of antibiotics in foods and medicines.