Monodisperse Core-Shell NaYF4:Yb3+/Er3+@NaYF4:Nd3+-PEG-GGGRGDSGGGY-NH2 Nanoparticles Excitable at 808 and 980 nm: Design, Surface Engineering, and Application in Life Sciences

Abstract

4 :Nd 3+-PEG-RGDS nanoparticles on both Hep-G2 and HeLa cells was determined, confirming no adverse effect on their survival and proliferation. The interaction of the nanoparticles with Hep-G2 cells was monitored by confocal microscopy at both 808 and 980 nm excitation. The NaYF 4 :Yb 3+ /Er 3+ @NaYF 4 :Nd 3+-PEG-RGDS nanoparticles were localized on the cell membranes due to specific binding of the RGDS peptide to integrins, in contrast to the NaYF 4 :Yb 3+ /Er 3+ @NaYF 4 :Nd 3+-PEG-Alk particles, which were not engulfed by the cells. The NaYF 4 :Yb 3+ /Er 3+ @NaYF 4 :Nd 3+-PEG-RGDS nanoparticles thus appear to be promising as a new non-invasive probe for specific bioimaging of cells and tissues. This development makes the nanoparticles useful for diagnostic and/or, after immobilization of a bioactive compound, even theranostic applications in the treatment of various fatal diseases.

Synthesis, Optical Properties, and Sensing Applications of LaF3:Yb3+/Er3+/Ho3+/Tm3+ Upconversion Nanoparticles

“…27-1427). β -NaYbF 4 showed a similar crystal structure (hexagonal) and UC emission spectra to those of LaF 3 -type nanoparticles, which have been reported in relevant studies [ 40 , 41 , 42 ]. Therefore, β-NaYbF 4 would not affect the crystal morphology and peak positions of the UC emissions of the LaF 3 UCNPs, as confirmed in the following section based on the PL spectra (Figure 4).…”

“…The fluorescence intensities of the UCNPs synthesized by the 1 h reaction with the addition of 2.5 and 5 mmol NaOH were significantly high, approximately 17 times that of the control sample. Most importantly, from Figure 4 , under the abovementioned two synthetic conditions, the positions of the characteristic emission peaks did not change because β-NaYbF 4 exhibited UC emission peaks similar to those of the LaF 3 nanocrystals [ 40 , 41 , 42 ].…”

Colloidally Stable P(DMA-AGME)-Ale-Coated Gd(Tb)F3:Tb3+(Gd3+),Yb3+,Nd3+ Nanoparticles as a Multimodal Contrast Agent for Down- and Upconversion Luminescence, Magnetic Resonance Imaging, and Computed Tomography

“…TEM microscope was equipped with an EDX energy dispersive spectrometer (EDAX; Mahwah, NJ, USA) used for analysis of the elemental composition of the nanoparticles. The crystal structure was verified by a selected area electron diffraction (SAED) as described in our previous work [30]. (3 mmol) was added dropwise and the mixture was kept at 75 • C (optionally 100 or 140 • C) for 3.5 h with stirring.…”

“…TEM microscope was equipped with an EDX energy dispersive spectrometer (EDAX; Mahwah, NJ, USA) used for analysis of the elemental composition of the nanoparticles. The crystal structure was verified by a selected area electron diffraction (SAED) as described in our previous work [30]. Dynamic light scattering (DLS) measurements (Zetasizer Ultra; Malvern, UK) provided the hydrodynamic diameter (D h ) and polydispersity (PD) calculated from the cumulant analysis of the intensity autocorrelation, assuming a single particle size mode.…”

Coordination mechanism of cyanine dyes on the surface of core@active shell β-NaGdF4:Yb3+,Er3+ nanocrystals and its role in enhancing upconversion luminescence

“…2E and 2F). Hydrophilic NaGdF4 and NaYF4 nanocrystals have been demonstrated by several authors to exhibit positive zeta potential after removal of OA [44][45][46] . Therefore, positively charged dyes do not have a high affinity to bind to the Ln 3+ cations of the surface of UCNCs due to electrostatic repulsion.…”