Magneto-Induced Hyperthermia and Temperature Detection in Single Iron Oxide Core-Silica/Tb3+/Eu3+(Acac) Shell Nano-Objects

Wet chemical synthesis of TGA capped Ag2S nanoparticles and their use for fluorescence imaging and temperature sensing in living cells

In this work, we describe a simple wet chemical route for preparing silver sulfide nanoparticles (Ag2S) encapsulated with thioglycolic acid (TGA). By using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray (EDS) microanalysis, transmission electron microscopy (TEM), and dynamic light scattering (DLS), we have found that these nanoparticles were enrobed by TGA molecules and they have an Ag/S ratio nearly equal to 2.2 and a nearly spherical shape with two average size populations. Photoluminescence (PL) spectroscopy has shown that these nanoparticles are highly luminescent, photostable and photobleaching resistant and they emit in the first biologic window with a band peaking in the NIR region at 915 nm. We have demonstrated through a 3-(4,5-dimethyl-thiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay protocol and using U-87 MG human living cells that these nanoparticles are biocompatible with a viability ratio higher than 80% for a concentration equal to 100 μg mL-1. By investigating the effect of pH, ionic strength and thermal quenching on the PL emission, we have shown that these nanoparticles provide a convenient stable tool to measure temperature in the biological range with a relative thermal sensitivity higher than 5% per °C and they may be used as suitable fluorescent probes for living cell imaging and intracellular temperature mapping.

Eu3+ and Tb3+ coordination compounds with phenyl-containing carbacylamidophosphates: comparison with selected Ln3+ β-diketonates

Materials based on Eu³⁺ and Tb³⁺ coordination compounds are of great interest due to their strong red and green luminescence. Appropriate selection of ligands plays a huge role in optimizing their photophysical properties. Another very helpful instrument for such optimization is theoretical modelling, which permits the prediction of the emissive properties of materials through intramolecular energy transfer analysis. The ligands that allow for achieving high efficiency of Eu³⁺ and Tb³⁺ emissions include carbacylamidophosphates (CAPh, HL). In this brief review, we summarize recent research for lanthanides CAPh-based coordination compounds of general formulas Cat[LnL]₄, [LnL₃Q] and [Ln(HL)₃(NO₃)₃], where Cat⁺ = Cs⁺, NEt4⁺, PPh₄ ⁺ and Q = 1,10-phenanthroline, 2,2-bipyridine or triphenylphosphine oxide, involving the use of thermal gravimetric analysis, X-ray analysis, and absorption and luminescence spectroscopy. We carried out a comparison with selected Ln³⁺ β-diketonates. Possibilities and developments of theoretical calculations on energy transfer rates are also presented.

Editorial for Special Issue "Luminescent Colloidal Nanocrystals"

The field of luminescent colloidal nanocrystals and the numerous nanosystems based on them has recently made a rapid breakthrough from initial basic research to real applications and devices [...].