Study On The Construction Of Luminescent Gold Nanoparticles And Organic Dyes Nanohybrids And Ratio Fluorescence Sensing

Ultra-small luminescent AuNPs?d<3 nm?has attracted much attention in biochemical sensing because of their unique optical propertie s,good biocompatibility,easy functionalization,high chemical stability and low toxicity,etc.Fluorescence spectroscopy has the advantages of simple analysis,low cost and high sensitivity,and it has become the most widely used sensing method.However,most of the fluorescent probes are mainly focused on the single emission intensity readings which are most likely to be affected by many factors,such as excitation intensity,instrument efficiency,photobleaching and the concentration of nanoprobes.The dual-emission fluorescence probe prepared by combining AuNPs with other technologies has higher sensitivity of analysis and detection,and can further improve the performance of AuNPs in applications such as molecular recognition and ion sensing.Organic dyes play an important role in biochemical sensors due to their rich variety,high brightness,multi chroma and good selectivity.The combination of ultra-small luminescent AuNPs and organic dyes can not only retain the intrinsic characteristics of each component,but also explore new properties,which provides a new method for the design of materials with required properties and functions.AuNP-BBS nanohybrids were synthesized through in-situ self-assembly of red-emitting AuNPs in the hydrophobic core,along with doping blue-emitting and polarity-responsive hydrophobic dye 4,4'-bis?2-benzoxazolyl?stilbene?BBS?.The nanohybrids consist of about10 crosslinked ultrasmall AuNPs in the hydrophobic core.The cross-linking interaction between multi-dentate thiol ligand and ultrasmall AuNPs offers remarkable stability without dye leakage,while thermo-sensitive pluronic F127 endows the nanohybrids two reverse signal responses toward temperature.In virtue of excellent features,the dual-emitting AuNP-BBS nanohybrids can be capable of ratiometric sensing of temperature with remarkable reversibility and high sensitivity(0.3396 ^oC^-1)in a wide temperature range of 10?-80?,and enable visual temperature measurements by the naked eye and pseudo-color imaging.Therefore,it can be utilized as an ultrasensitive and reversible ratiometric temperature sensor.The synthesis of AuNP-BBS nanohybrids provides a useful guidance for preparing uniform hybrid nanomaterials with remarkable stability and desired functions.The surface chemical properties of AuNPs have great influence on the sensitivity,specificity,detection limit and detection range of these sensors.Based on so many advantages of the combination of organic dyes and ultra-small luminescent AuNPs,we have designed and prepared a series of nanoprobes such as AuNPs@RITC-CS,Adm SH functional modification AuNP-TF5PPH2,EMP-AuNPs?1.4:1/2.8:1?,EMP functional modification AuNP-MAB,EMP functional modification AuNP-TF5PPH2 and EMP-AuNPs?5.6:1?,and they were used to explore their potential as Cu²⁺probes.The results show that EMP-AuNPs?5.6:1?can realize high selectivity visualization and high sensitivity Cu²⁺ratio detection,which will provide a new method and idea for intracellular Cu2+detection.