| As a very important rare earth luminescent material,upconversion luminescence nanoparticles(UCNPs)can convert long wavelength near infrared light into short wavelength ultraviolet or visible light.UCNPs have significant advantages,such as narrow emission band,low toxicity,good chemical stability and light stability,strong tissue penetration depth,no spontaneous fluorescence interference(noise)of biological samples,and less damage to biological samples.These unique anti-Stokes properties make the upconversion nanomaterials a useful application in solar cells,safety markers,biological imaging,drug delivery and release,and detection.The rare earth upconversion nanomaterials with ?-NaYF4 as the matrix material are the most widely used materials with the highest luminous efficiency.At present,most of the synthesized P-NaYF4 upconversion luminescence nanomaterials have hydrophobic surfaces,and there are water solubility and biocompatibility problems in practical applications,which is an obstacle to further development.It is a great challenge to modify and improve the upconversion nanomaterials in a suitable way.On the other hand,the upconversion nanomaterials as the core,after surface modification and then combine with other organic dye to meet the application in different areas,which is a problem that needs to be solved.In this paper,an upconversion luminescence nanocomposite structure for the detection of Cu2+ was developed by synthesizing upconversion luminescence nanoparticles.We carry out the study in the following aspects:1.Synthesis and surface modification of upconversion luminescence nanoparticles with p-NaYF4 as matrix.At present,?-NaYF4 as the matrix material is the most efficient method for the synthesis of upconversion luminescence nanomaterials.In this paper,the upconversion luminescence nanoparticles with excellent luminescent properties were synthesized by hydrothermal reaction,doping Yb3+/Er3+/Gd3+,Yb3+/Ho3+/Gd3+,Yb3+/Tm3+/Gd3+ with p-NaYF4 as the matrix.The upconversion luminescent nanorods with P-NaYF4 matrix is uniform with average diameter of 17 nm and the average length of 109 nm.After doping Yb3+/Er3+/Gd3+,Yb3+/Ho3+/Gd3+,Yb3+/Tm3+/Gd3+,upconversion luminescent nanorods have different luminescence under the excitation of 980 nm continuous wave laser.The emission color includes red,green and blue.The synthesized ?-NaYF4:Yb,Er,Gd was encapsulated with a layer of ultrathin silica through a water-in-oil reverse microemulsion strategy to enhance its dispersion in water and biocompatibility so that it can be better used in analytical testing.(in chapter 2)2.Organic dye TSPP modified upconversion luminescence nanoparticles with high efficiency luminescence resonance energy transfer for the detection of Cu2+ in cell lysatesWe synthesized a Cu2+ responsive organic dye TSPP modified upconversion luminescence nanoprobe,?-NaYF4:Yb,Er,Gd@SiO2-TSPP.The nanoprobe composed of ?-NaYF4:Yb,Er,Gd@SiO2 upconversion luminescence nanorods and Cu2+-reactive organic dye TSPP.The nanosensor is based on the high efficiency luminescence resonance energy transfer(LERT)process between the upconversion luminescence nanorods and the organic dye,in which ?-NaYF4:Yb,Er,Gd nanorods worked as the energy donor and Cu2+-responsive TSPP as the acceptor.The formationof the TSPP-Cu2+ complex resulted in the upconversion quenching of the nanoprobe at 545 nm and the detection of Cu2+ based on the change in emission intensity at 545 nm to 659 nm.A linear response was obtained in the range of Cu2+ concentration of 5?M to 0.16 mM,and the detection limit was calculated to be 2.16 ?M.Because the prepared ?-NaYF4:Yb,Er,Gd@SiO2-TSPP has good dispersion in water and biocompatibility,which can be highly selective detection of cell lysates Cu2+.The analysis of Cu2+ in biological systems was evaluated by the determination of Cu2+spiked in Hela cell lysates with recoveries ranging from 98%to 102%and RSD below 5.0%.(in chapter 3)... |
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