Synthesis And Properties Of UCNPs And Hemicyenine Derivatives-based Nanoprobes

As a kind of important luminescent materials,rare earth-doped upconversion nanoparticles’(UCNPs)luminence can be excited with 980 nm light generally,which can effectively avoid biological autofluorescence interference and has deeper biological tissue penetrating ability.UCNPs,as a new type of nanometer materials in biosensing and bioimaging,have attracted much attention in recent years.Organic fluorescent probes can realize simple and rapid detection of many species.However,most of their excitation wavelengths are shorter and can’t satisfy the requirement of deep organisms’ imaging.Therefore,it is of great significance to employ UCNPs and molecular probes to construct nanoprobes for NIR ratiometric luminescence detection.In this article,using luminescence resonance energy transfer(LRET)between Er3+/Tm3+doping upconversion nanoparticles and two hemicyenine derivatives 1/2,nanoprobes have been built for NIR ratiometic detection of arginine/hydrazine and pH.The main contents are as follows:1.Using hydrothermal method,Er3+doped upconversion nanoparticles NaYF4:Yb,Er were synthesized.After surface modification and electrostatic adsorption,the nanoparticles and the arginine/hydrazine sensitive hemicyenine derivative 1 are assembled to obtain the nanoprobe 1-PAA-UCNPs(Er).The response mechanisms of 1-PAA-UCNPs(Er)toward arginine and hydrazine were explored.Selecting the ratio of upconversion luminence at 660 nm and 525 nm(UCL660/UCL525)as detection signal,the quantitative detection ranges of 1-PAA-UCNPs(Er)toward arginine and hydrazine are 520-1235 μM and 122-610μM with the detection limits of 156 μM and 12.4 pM were respectively obtained.It also has good anti-interference ability and photostability/thermal stability,and we succeed in applying the nanoprobe to arginine/hydrazine upconversion luminence imaging and lysosome localization test in HeLa cells.We first use UCNPs to construct arginine/hydrazine near-infrared ratiometric detection system.2.We use thermal decomposition method to synthesize Tm3+-dopedβ-NaGdF4@NaGdF4:Yb,Tm@NaYF4 upconversition nanoparticles.Electrostatic adsorption method is used to assemble the pH sensitive hemicyenine derivatives 2 onto the surface of PAA-modified water-soluble nanoparticles to obtain nanoprobe 2-PAA-UCNPs(Tm).The as-developed nanoprobe exhibits good anti-disturbance ability,reversible pH sensing ability,and a linear response range of pH 6.6-9.0 from its upconversion emission spectra.With this probe,pHi fluctuation in living cells has been successfully tracked via ratiometric upconversion luminescence imaging.