RENPs Upconversion/NIR Ⅱ Luminescence Optimization And Applications For Temperature Sensing And Diagnosis

Rare earth nanoparticles(RENPs)have excellent optical properties and are a promising luminescent nanomaterial.RENPs have the advantages of tunable UV/Vis/IR emission and large Stokes shift,low background interference,high penetration and sensitivity,especially in biological samples to reduce photodamage.These properties make RENPs available for a wide range of application levels,including bioimaging,disease monitoring,tumor diagnosis and treatment,temperature sensing,and many others.The presence of possible surface defects,energy loss due to cross-relaxation,unfavorable energy migration and energy competition between elemental energy levels can seriously affect the optical properties of RENPs,making their upconversion luminescence(UCL)or downconversion luminescence(DCL)weaker,further leading to deficiencies of their application in detection,tumor therapy and imaging.For the photodynamic therapy(PDT)of RENPs,the weak photodynamic effect can be caused by the aggregation quenching of some traditional organic photosensitizers,rigid planar structure,hydrophobic properties and other factors,which also affect the tumor treatment effect.Based on the above problems,this paper explores the luminescence performance of fluoride with different crystals,structures and doping elements and ratios,based on fluoride RENPs,and optimizes the luminescence performance by optimizing the structures,elements and ratios,and further investigates the application of the optimization in detection,imaging and tumor phototherapy.The main contents are briefly described as follows.1.To investigate the optimization of UCL and NIR Ⅱ emission with NaYF4:Yb,Er@NaYF4:Nd,Ce,Tm@NaYF4 nanoparticles as the research substrate under1064 nm excitation.The optimization of UCL was achieved by designing nanoparticles with different ratios of Nd,Ce,and Tm doping and optimizing their energy level structures.Moreover,the optimization method mitigates the weakening of NIR Ⅱ emission in Er3+ due to energy competition from UCL enhancement.The optimized nanoparticles showed significant differences in UCL enhancement due to temperature increase under 808 nm and 1064 nm excitation,and were applied to the temperature ratiometric detection of surface coatings with good results.2.Nanoparticles with bright UCL and NIR Ⅱ emission under 808 nm excitation were prepared by co-precipitation method.The variation of the characteristic wavelength emission of different elements through the core-shell-shell(YOF@YOF@YOF)structure and the cross-relaxation(between Er3+ and Ce3+)strategy is mainly due to the energy back transfer(EBT)from Er3+ ions to Nd3+ ions.Since the UCL and NIR Ⅱ emitting elements are separated,the energy competition between different emission processes of the same element is avoided.Thus,the NIR Ⅱ emission(~1064 nm and~1350 nm)and the two-photon UCL(550 nm)can be enhanced simultaneously for 808 nm excitation.The wide fluorescence lifetime range of different nanoparticles(64.39 μs-7.644 ms)is a well-researched basis for future lifetime imaging.The final optimized nanoparticles have clear in vivo NIR Ⅱ imaging(vascular and bone imaging).3.Degradable peptide-modified upconversion nanoparticles were designed for NIR Ⅱ imaging and UCL-guided PDT of triple-negative breast cancer(TNBC).Ultrasmall RENPs and polymer chains m PEG-PLGA were polymerized into nanomicrospheres by a double emulsion method,and photosensitizer molecules were added during the polymerization process to generate composite nanoparticles.The strategy enhances the650 nm emission at 980 nm excitation with 38.3% energy transfer efficiency,and the designed core-shell structured RENPs have better NIR Ⅱ imaging capability.The nanoparticles have good PDT effects and can be degraded to nanoparticles smaller than6 nm in size.Due to the positive targeting imaging effect of c MBP peptide on MET and the negative targeting effect of enhanced permeability retention effect(EPR),this luminescent probe can identify TNBC cells when injected i.v.Such design enables the ZUPEA probe to have diagnostic and therapeutic functions,providing new ideas and prospects for the application of RENPs in the clinical treatment of tumors.4.Designed nanoplatform combined with natural chlorophyll for bimodal luminescenceguided antitumor surgery and PDT.Luminescent phosphors optimized using a genetic algorithm(GA)were used.When phosphor with different emitted light(red,green and blue)was combined with chlorophyll as control,the phosphor with red emission as energy donor had higher PDT efficiency when combined with chlorophyll.Synthetic nanoparticles can be used for surgical navigation due to the EPR.The Near Infrared imaging is performed more effectively at cancer lesions than in normal and paracancerous tissues.Thus,the final luminescent powder with high dual-mode luminescence for guiding surgery will facilitate its further application in miniature noninvasive endoscopic clinical surgical navigation.5.Nanoplatforms with mesoporous structures of spherical UCNPs bound to the semiconductor element Mn were designed,and fluorescence and absorption methods can be used to detect hydrogen peroxide(H2O2)and glutathione(GSH).The nano-platform has effective PDT effects in vivo and in vitro.When combined with Anti-PD-L1,it exposes cancer cells to the immune system and enhances the abilities of the immune system to kill and clear tumor cells as Anti-PD-L1 can specifically bind to the PD-L1 receptor on the surface of tumor cells.Combining Anti-PD-L1 with PDT for combination therapy has achieved very good tumor treatment results.