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1.
Chemistry ; 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33476058

RESUMO

Luminescent materials doped with Ln 3+ ions have attracted in recent years a large amount of attention for their applications as optical thermometers based both on down shifting and upconversion processes. This study presents research done on development of highly sensitive optical thermometers in the physiological temperature range based on PMMA (poly(methyl methacrylate)) films doped with two series of visible Ln 3+ complexes (Ln 3+ = Tb 3+ , Eu 3+ and Sm 3+ ) and silica (SiO 2 ) nanoparticles (NPs) coated with these PMMA films. The best performing PMMA films doped with Tb 3+ and Eu 3+ complexes, was the PMMA[TbEuL 1 tppo]1 film (L 1 = 4,4,4-trifluoro-1-phenyl-1,3-butadionate and tppo = triphenylphosphine oxide), which showed good temperature sensing S r = 4.21% K -1 at 313 K, while for the PMMA films doped with Tb 3+ and Sm 3+ complexes, was the PMMA[TbSmL 2 tppo]3 film (L 2 = 4,4,4-trifluoro-1-(4-chlorophenyl)-1,3-butadionate) showed S r = 3.64% K -1 at 313 K. Additionally, SiO 2 nanoparticles coated with the best preforming films from each of the series of PMMA films (Tb-Eu and Tb-Sm) and their temperature sensing properties were studied in water showing excellent performance in the physiological temperature range ( PMMA[TbEuL 1 tppo]1@SiO 2 S r = 3.84% °C at 20 °C and PMMA[TbSmL 2 tpp]3@SiO 2 S r = 3.27% °C at 20 °C) and the toxicity of these nanoparticles on human cells was studied showing that they are not toxic.

2.
J Biol Inorg Chem ; 25(6): 875-885, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32719971

RESUMO

L-ascorbic acid 2-phosphate magnesium (APMg) salt is a vitamin C derivative frequently used as a raw material in cell and tissue therapy. APMg is not only used as a replacement of the unstable ascorbate, but also shows additional cell-biological functionalities. However, its unknown structural characteristics hamper the mechanistic elucidation of its biological role. Therefore, different techniques were applied for APMg structure characterization. Firstly, the stoichiometric composition was characterized by its solvent, ligand and magnesium content. No crystals of APMg could be obtained; however, a single crystal of APNa, the sodium salt of l-ascorbic acid 2-phosphate, was successfully obtained and its crystal structure was elucidated. FT-IR was applied to further clarify the structure of solid APMg. Finally, the structure of APMg in aqueous solution was explored by potentiometric titration as well as FT-IR.

3.
Chemistry ; 25(69): 15944-15956, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31614041

RESUMO

Two series of novel NIR-emissive complexes of Nd3+ , Sm3+ , Er3+ and Yb3+ with two different ß-diketonate ligands (L1 =4,4,4-trifluoro-1-phenyl-1,3-butadione and L2 =4,4,4-trifluoro-1-(4-chlorophenyl)-1,3-butadione) are reported. The neutral triphenylphosphine oxide (tppo) ligand was used to replace coordinated water molecules in the first coordination sphere of the as-obtained [Ln(L1(2) )3 (H2 O)2 ] complexes to afford water-free [Ln(L1(2) )3 (tppo)2 ] molecular species. Upon replacement of water molecules by tppo units, the NIR emission lifetimes of the Nd3+ , Er3+ and Sm3+ complexes increase by about one order of magnitude up to values of ≈9, 8 and 113 ms while Yb3+ complexes reach intrinsic quantum yields as high as to ΦYb =6.5 %., which are remarkably high for fully hydrogenated complexes. Vibrational quenching by CH and OH oscillators has been quantitatively assessed by implementing the Förster's model of resonance energy transfer on the basis of experimental data. This study demonstrates that highly efficient NIR-emitting lanthanide complexes can be obtained with facile, cheap and accessible syntheses through a rational design.

4.
J Biophotonics ; 12(9): e201800470, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31134739

RESUMO

The wings of some insect species are known to fluoresce under illumination by ultraviolet light. Their fluorescence properties are however, not comprehensively documented. In this article, the optical properties of one specific insect, the Trictenotoma childreni yellow longhorn beetle, were investigated using both linear and nonlinear optical (NLO) methods, including one- and two-photon fluorescence and second harmonic generation (SHG). These three distinct optical signals discovered in this beetle are attributed to the presence of fluorophores embedded within the scales covering their elytra. Experimental evidence collected in this study indicates that the fluorophores are non-centrosymmetric, a fundamental requirement for SHG. This study is the first reported optical behavior of this type in insects. We described how NLO techniques can complement other more convenient approaches to achieve a more comprehensive understanding of insect scales and integument properties.


Assuntos
Besouros/fisiologia , Imagem Óptica , Asas de Animais/fisiologia , Animais , Cor , Feminino , Corantes Fluorescentes , Processamento de Imagem Assistida por Computador , Luz , Masculino , Microscopia de Fluorescência , Dinâmica não Linear , Fótons , Espectrometria de Fluorescência , Espectrofotometria , Espectrofotometria Ultravioleta , Asas de Animais/diagnóstico por imagem
5.
Dalton Trans ; 48(10): 3187-3192, 2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30640331

RESUMO

In this paper, a novel kind of tristrontium sodium antimony(v) oxide (NaSr3SbO6:Mn4+; NSSO:Mn4+) material was developed, whose crystal structure is different from the well-researched Mn4+-doped antimoniate double pervoskite materials. The optimal NSSO:0.006Mn4+ can be mainly excited using ultraviolet/near-ultraviolet (UV/n-UV) and partial blue lights with a high quantum yield of 46% upon 365 nm UV excitation and good temperature dependent performance.

6.
Interface Focus ; 9(1): 20180052, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30603071

RESUMO

Upon illumination by ultraviolet light, many animal species emit light through fluorescence processes arising from fluorophores embedded within their biological tissues. Fluorescence studies in living organisms are however relatively scarce and so far limited to the linear regime. Multiphoton excitation fluorescence analyses as well as nonlinear optical techniques offer unique possibilities to investigate the effects of the local environment on the excited states of fluorophores. Herein, these techniques are applied for the first time to study of the naturally controlled fluorescence in insects. The case of the male Hoplia coerulea beetle is investigated because the scales covering the beetle's elytra are known to possess an internal photonic structure with embedded fluorophores, which controls both the beetle's coloration and the fluorescence emission. An intense two-photon excitation fluorescence signal is observed, the intensity of which changes upon contact with water. A third-harmonic generation signal is also detected, the intensity of which depends on the light polarization state. The analysis of these nonlinear optical and fluorescent responses unveils the multi-excited states character of the fluorophore molecules embedded in the beetle's elytra. The role of form anisotropy in the photonic structure, which causes additional tailoring of the beetle's optical responses, is demonstrated by circularly polarized light and nonlinear optical measurements.

7.
J Am Chem Soc ; 140(35): 10975-10979, 2018 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-30122038

RESUMO

Multiplex imaging in the red and near-infrared (NIR) should be an enabling tool for the real-time investigation of biological systems. Currently available emitters have short luminescent lifetimes, broad absorption and emission bands, and small Stokes shifts, which limits multiplexing in this region to two colors. NIR-emitting luminescent lanthanide (Ln) complexes carrying hydroporphyrin (chlorin) sensitizing antennae are excitable in the red through the narrow, intense and tunable chlorin absorptions. Both emission- and excitation-based multiplexing are possible, the former by exciting the same antenna appended to different Lns, the latter by attaching different chlorins with nonoverlapping absorptions to the same Ln. The combination of excitation and emission spectroscopies allows for the straightforward differentiation of up to four different complexes.

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