Preparation And Performance Study Of Novel Fluorescent Probes Of Cysteine And Rhodamine Derivatives Functionalized Nano-silver

Nano silver(Ag NPs)has the advantages of high surface activity,superior photoelectric properties,and good biocompatibility.Based on this,the surface can be modified for cell imaging and fluorescent probe detection.Cysteine(L-Cys)is often used to modify the surface of precious metals because of its characteristic group sulfhydryl group.Rhodamine 6G derivative(Rh6G2)has a simple structure,is easy to design and modify,and has excellent fluorescence properties,which can be used in chemistry,environmental analysis and biomarking.This article takes 13nm Ag NPs as the center,introduces L-Cys and Rh6G2,constructs a new type of fluorescent probe Ag NPs-L-Cys-Rh6G2,and launches the probe in optical performance,reaction mechanism,cell imaging,etc.,Mainly including the following aspects:1.Sulfhydryl compounds are easy to combine with precious metal particles to form a stable structure.Ag NPs and L-Cys with sulfhydryl groups are self-assembled to achieve surface modification of Ag NPs.At the same time,Rh6G2 is introduced.At this time,the exposed-NH₂ of L-Cys is combined with The-CHO of Rh6G2 undergoes a Schiff base reaction,which makes the three tightly combined to form a new fluorescent probe Ag NPs-L-Cys-Rh6G2.The preparation conditions and stability are studied,and the fluorescent probes are characterized by means of transmission electron microscopy,ultraviolet-visible spectroscopy,fluorescence spectroscopy,infrared spectroscopy,and electrochemical analysis.The results show that when the volume ratio of H₂O/CH₃OH is 1:1,the ratio of n(L-Cys):n(Rh6G2)is 1,and the added amounts of Ag NPs,L-Cys and Rh6G2 are 0.073?mol,0.15?mol,0.15?mol is the best condition for probe preparation.In the investigation experiment of the influence of time,temperature,p H,anion and cation on the fluorescent probe molecule,it was found that the probe can specifically recognize Hg²⁺and Cu²⁺under the Hepes/CH₃OH buffer system and Tris-HCl/CH3OH buffer system,respectively.It can be used to detect two kinds of ions.Therefore,it provides a basis for follow-up experimental research.2.In the Hepes/CH₃OH buffer system(V_Hepes/V_CH3OH=1:1,p H=7.0),explore the specific recognition of Hg²⁺by the probe,and the results show that the fluorescent probe molecule has high selectivity to Hg²⁺and does not Interfered by other anions and cations,within the Hg²⁺concentration range of 1×10^-4 mol/L-4.5×10^-4 mol/L,the fluorescence intensity shows a linear relationship,the linear equation is y=1547.45?-612.63,and the correlation coefficient is R²=0.99,the detection limit is 5.98×10^-8mol/L.The probe was applied to the bottom mud of the Nongren River for a standard recovery experiment.The average recovery rate was between 95.97-97.82%,and the relative standard deviation was within the range of 1.23-5.94%.It can be seen that the fluorescent probe has high selectivity,small relative deviation,simple preparation,convenient sample measurement,and can be used as an effective tool for actual detection.In addition,Ag NPs-L-Cys-Rh6G2 and L-Cys-Rh6G2 probes were introduced into Hela cells,and the effects of the two probes on the activity changes of Hela cells and cell imaging experiments showed that the cytotoxicity of the probes introduced into Ag NPs was significantly reduced.The cell permeability increased significantly,and the detection of Hg²⁺by Ag NPs-L-Cys-Rh6G2 showed brighter red fluorescence,which laid the foundation for the introduction of fluorescent probes into the field of biomedicine.3.Explore the specific recognition of Cu²⁺by the probe in the Tris-HCl buffer system(V_Tris-HCl/V_CH3OH=1:1,p H=7.0).The results showed that under the interference of other anions and cations,the solution of the probe combined with Cu²⁺was purple-red,and the fluorescence intensity and absorbance were significantly enhanced.When the Cu²⁺concentration range was 1.75×10^-4mol/L-6.5×10^-4mol/L,There is a linear relationship between UV absorbance and Cu²⁺concentration.The linear equation is y=0.2497?-0.1349,the linear correlation coefficient R²=0.9929,and the detection limit is 8.77×10^-6 mol/L.In the actual detection of Cu²⁺in sediments,the average recovery rate is between 90.00-95.59%,and the relative standard deviation is between1.32-5.69%.At the same time,the imaging experiment results in Hela cells show that the introduction of Ag NPs can effectively reduce heavy metals Ion damage to cells,this pair of probes shows great potential for application in biological cytology research.