Construction And Analytical Application Of Silver-Doped Gold-Based Bimetallic Nanoclusters Fluorescent Probe

Ultra-small luminescent metal nanoclusters(MNCs,<3nm)composed of several to several hundred metal atoms have become a new type of functional material.It has unique properties such as ultra-small size,large Stokes shift,strong resistance to photobleaching,good dispersibility and biocompatibility.It has attracted extensive attention in the fields of fluorescence sensing,bioimaging and catalysis.Researchers have developed various methods to synthesize water-soluble MNCs,especially gold-silver bimetallic nanoclusters(AuAg NCs)that exhibit enhanced luminous efficiency and light stability due to Forster resonance energy transfer(FRET)and synergistic effects.Three red-emitting AuAg NCs have been synthesized in this article,they have good fluorescence properties and stable properties.Based on their fluorescence properties,the following work has been carried out:Tiopronin(TPN)is a protective and reducing agent to synthesize super luminous fluorescent AuAg NCs.The fluorescence of this clusters has a specific quenching response to Fe³⁺,and shows a good linearity(R²=0.999)when the Fe³⁺concentration is 0.5-80?M.The detection limit(LOD)is 0.15?M,which meets the detection requirements of Fe³⁺in actual samples.Further studies have found that ascorbic acid can restore the fluorescence of Fe³⁺@AuAg NCs,and has a good linearity between 0.2-80?M(R²=0.999),and the LOD is 0.06?M.When it is applied to the detection of healthy human serum samples,it has a good recovery rate and precision.Using 4,6-diaminopyrimidine-2-thiol(DMT)as a ligand,AuAg NCs with strong red light were synthesized.The clusters have a very sensitive fluorescence quenching response to I^-,and a linear equation is established in the range of 0.01-70?M,and the detection limit is as low as 5nM,which meets the actual detection of I^-in serum.Based on the fluorescence recovery phenomenon of the I^-@AuAg NCs complex after adding Ag⁺,it can be further used to detect Ag⁺.It has good linearity in the range of 5.0-70?M,and the detection limit is 150nM,which can basically meet the requirement for Ag⁺detection.Captopril(CAT)is used as a stabilizer,and THPC is introduced as a reducing agent to synthesize red-emitting AuAg NCs.The fluorescence material has a sensitive quenching response to Cu²⁺.A linear equation is established in the range of 0.05-25?M,and the detection limit is 15.0nM,which meets the needs of Cu²⁺detection and has been successfully used for the detection of Cu²⁺in human serum.This material is made into a fluorescent paper sensor.Under a 365nm ultraviolet lamp,the red luminescence of the fluorescent test paper gradually becomes darker with the concentration of Cu²⁺from 0 to 100?M,it can be used for visual detection of Cu²⁺.