Synthesis And Biological Application Of Dual-function Near-infrared Persistent Luminescence Material

Near-infrared（NIR）persistent luminescence materials（PLMs）are materials that continuously emit NIR persistent luminescence（Pers L）after stopping excitation.They have advantages such as stable optical properties,long duration of luminescence,deep tissue penetration,no biological self-fluorescence interference,etc.Therefore,NIR PLMs have broad application prospects in biomedical fields such as drug tracer,tumor imaging,image-guided therapy,and are considered as a new generation of fluorescent probes.At present,most of the NIR PLMs just have a single function,which is difficult to meet the complex biomedical applications.In order to make the NIR PLMs better applied in the biomedical field,this paper developed two kinds of NIR PLMs which can simultaneously realize the dual function of imaging and treatment,and conducted a preliminary study on their biomedical applications.The main research contents are as follows:（1）In this section,Zn₃Ga₂Sn O₈:0.5%Cr³⁺,2%Yb³⁺,1%Ho³⁺（ZGS）was synthesized by combustion method.ZGS has both NIR Pers L and up-conversion luminescence（UCL）properties,it can be excited by 659 nm LED light and generate 700 nm NIR Pers L,and produce UCL at 546 nm and 660 nm when excited by a 980 nm NIR laser.First,the good in situ excitation efficiency of ZGS was demonstrated by comparing the 254 nm and 659 nm excited materials covered with pig skin tissue.Then,ZGS was designed as an image-guide photodynamic therapy（PDT）system,which conducts imaging by its NIR Pers L and PDT by sensitizing photosensitizers by its UCL.We first loaded the photosensitizer Bengal Rose red（RB）absorbed at about 546 nm on the surface of ZGS material,and loading the anoxic prodrug tirapazamine to enhance the PDT effect,and coating hyaluronic acid to enhance the tumor targeting.Experiments on cytotoxicity,cell uptake and cell level PDT have proved that the PDT system has low toxicity to normal cells,has good tumor cell binding ability,and can effectively kill tumor cells when stimulated by 980 nm laser.The results show that the PDT system can be used in the treatment of tumor and has a broad application prospect.（2）In this section,a novel PLM LiYGeO₄:Bi³⁺,Pr³⁺,which can be excited by X-ray,is developed by means of co-doping.This material has both ultraviolet（UV）Pers L with a peak at 352 nm and NIR Pers L with a peak at 734 nm.First,a series of LiYGeO₄:Bi³⁺materials with different doping concentrations of Bi³⁺were synthesized by high temperature solid phase method.LiYGeO₄:Bi³⁺have strong UV Pers L peak,and the optimal doping concentration of Bi³⁺was determined by comparing the Pers L spectrum and the Pers L decay curve.Then,the materials with UV and NIR double emission were obtained by co-doping Pr³⁺.After optimizing the doping concentration of Pr³⁺,the material with best Pers L performance,LiYGeO₄:0.1%Bi³⁺,0.1%Pr³⁺（LYGBP）,were obtained.CCD camera tests show that LiYGeO₄:Bi³⁺,Pr³⁺has more than 8 h Pers L,and can be stimulated by NIR laser or NIR LED light after the Pers L attenuation.With both UV and NIR luminescence properties,LiYGeO₄:Bi³⁺,Pr³⁺are expected to be designed as a NIR Pers L image-guided PDT system,the UV Pers L can stimulate photosensitizer for PDT,and the NIR Pers L has application potential in the field of biological imaging.In this study,pork tissue was used to simulate the biological environment in vivo to study in situ excitation and repeated excitation imaging,which preliminarily verified the imaging potential of LYGBP.