Nanoparticles (NPs) which are innovation and research focus in drug delivery systems, still have some disadvantages limiting its application in clinical use, such as short circulation time, recognition and clearance by reticuloendothelial system (RES) and passive targeting in certain organs. However, the recent combination of natural components and nanotechnology has offered new solutions to address these problems. A novel biomimetic platform consisting of nanoparticle core and membrane shell, such as cell membrane, exosome or vesicle vastly improves properties of nanoparticles. These coated nanoparticles can replicate the unique functions of the membrane, such as prolonged blood circulation, active targeting capability and enhanced internalization. In this review, we focus on the newest development of biological-camouflaged nanoparticles and mainly introduce its application related to cancer therapy and toll-like receptor.
Generally, the emission intensity and afterglow of the near infrared phosphors can be improved by co-doping the sensitizer. In this work, Bi3+ ions as sensitizer are introduced into the near infrared phosphor Mg3Y2Ge3O12:Cr3+, and the luminescence properties are investigated. According to the principle of radius adaptation, Bi3+ ions would occupy eight coordinates in the host instead of Y3+ and Mg2+. Through structural refinement, theoretical calculation and experimental phenomena, there are two kinds of luminescent sources for Bi3+ ions, which come from 3P1 → 1S0 (441 nm) and MMCT (330 nm), respectively. In addition, the substitution of Bi3+ for Mg2+ will result in inequivalent substitution forming defects (BiMg·), and the trap depth is 0.55 eV. For Bi3+ and Cr3+ co-doped Mg3Y2Ge3O12, there are two factors can that can affect the luminescent properties of Cr, which are energy transfer and defects. The samples are obtained with three times the original emission intensity with the introduction of defects. At the same time, Bi3+ ions capture electrons to form new electron traps Bi2+ (Bi3+ + e-) and the trap depth is 0.81 eV. Therefore, under the action of two traps BiMg· and Bi2+ (Bi3+ + e-), the afterglow characteristics of the samples are improved and the time can reach 1.5 h. 相似文献
Cr3+ doped LaGaO3 phosphor was prepared by hydrothermal reaction method with post-annealing treatment. XRD pattern showed the pure orthorhombic phase of LaGaO3 at an annealing temperature of 1000 °C. TEM image showed the particles in the range 40-120 nm. The bandgap energy and Urbach tail increased in the doped sample as compared to the undoped sample as estimated from UV–visible diffuse reflectance spectra. PL excitation spectra showed peaks in UV, blue and orange regions. The emission spectra showed broadband with peaks in the NIR region due to emission from 4T2 and 2E states. The intermediate strength of the crystal field has been calculated from the estimated spectroscopic parameter. The average lifetime was found to be in the ms range. Afterglow decay was also recorded. From the low-temperature PL, the zero phonon line, stokes shift energy, vibrational energy and Huang-Rhys parameter were calculated. With rising the temperature, PL emission peak intensity and lifetime values decreased and FWHM increased because of increased numbers of electrons in 4T2 state and increasing non-radiative transition. Temperature-dependent peak intensity ratios and lifetime values were utilized for temperature sensing applications in below room temperature and above room temperature. The results indicate the possibility of present phosphor to be used as optical nanothermometer. 相似文献
Energy transfer among the co-doped activators is an efficient route to achieve color-tunable emission in inorganic phosphors.Herein,photoluminescence tuning from blue to cyan has been achieved in the Lu_2MgAl_4 SiO_(12);Eu~(2+),Ce~(3+)phosphors by varying the Ce~(3+) concentration with a fixed Eu~(2+)content.With the further introduction of a Mn~(2+)-Si4+couple into the host lattice,the emission color can be tuned to red through the energy transfer of Eu~(2+)and Mn~(2+).The luminescence properties and the energy transfer mechanism were studied in detail.The energy transfer from Eu~(2+)to Ce~(3+)is certified as a dipolequadrupole interaction with the energy transfer efficiency of 41.4% and Eu~(2+)to Mn~(2+)belongs to a dipole-dipole interaction with the energy transfer efficiency of 94.3%.The results imply that this singlephased Lu_2MgAl4 SiO_(12):Eu~(2+),Ce~(3+),Mn~(2+)phosphor has a potential prospect for application in near-UV chip pumped white light emitting diodes. 相似文献
High-efficient Ce3+/Tb3+ co-doped Ba3Y2B6O15 phosphors with multi color-emitting were firstly prepared, and their structural and luminescent properties were studied by XRD Rietveld refinement, emission/excitation spectra, fluorescence lifetimes as well as temperature-variable emission spectra. Upon 365?nm excitation, the characteristic blue Ce3+ band along with green Tb3+ peaks were simultaneously found in the emission spectra. Moreover, by increasing concentration of Tb3+, a blue-to-green tunable emitting color could be realized by effective Ce3+→Tb3+ energy transfer. Furthermore, all Ba3Y2B6O15: Ce3+, Tb3+ phosphors exhibit high internal quantum efficiency of ~?90%, while the temperature-variable emission spectra reveal that the phosphors possess impressive color stability as well as good thermal stability (T50 =?~?120?°C). The results indicate that these efficient color-tuning Ba3Y2B6O15: Ce3+, Tb3+ might be candidate as converted phosphor for UV-excited light-emitting diodes. 相似文献
Garnet-type Ta-doped Li7La3Zr2O12 (LLZTO) electrolyte suffers from unstable chemical passivation under air exposure, responsible for the poor interfacial wettability and conductivity with Li metal. Instead of conventional methods to remove surface contaminants by mechanical polishing, acid etching and high temperature reduction, herein we propose a simple strategy of interfacial gas release and detergency to smartly convert Li2CO3 passivation layer into ion-conductive Li3PO4 domains at mild temperature (∼200 ℃). The in-situ formation of PH3 vapor and its phosphorization enables a dramatic decrease of Li/garnet interfacial resistance down to 2 Ω cm2 at room temperature (RT). The improved interfacial wettability and conductivity endow the symmetric cells with ultra-stable galvanostatic cycling over 1500 h and high critical current density of 2.6 mA/cm2. The high coulombic efficiency of Li plating enables a high reversibility of solid-state NCM811/Li cells even under a low N/P ratio (∼4) and high cut-off voltage of 4.5 V at RT. The prototype of fluoride-garnet solid-state batteries are successfully driven as rechargeable system (rather than widely known primary battery) with high conversion capacity (400 ∼ 500 mAh/g) and high-rate performance (251.2 mAh/g at 3 C). This interface infiltration-detergency approach provides a practical solution to the achievement of high-energy solid-state Li metal batteries. 相似文献