High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

Abstract

Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging.

d‐Glucuronic Acid‐Coated Ultrasmall Paramagnetic Ln2O3 (Ln = Tb, Dy, and Ho) Nanoparticles: Magnetic Properties, Water Proton Relaxivities, and Fluorescence Properties

“…As shown in Figure A, the spectrum of the nanoparticle solution sample showed 5 D 4 → 7 F 6 and 5 D 4 → 7 F 5 transitions at 491 and 545 nm, respectively, similar to those observed in the spectrum of free Tb 3+ ion solution whereas no such transitions were observed in the spectrum of triple‐distilled water, indicating that the transitions originated from Tb of d ‐glucuronic acid‐coated ultrasmall Tb 2 O 3 nanoparticles. These results were consistent with literature . In addition, the nanoparticle solution sample showed fluorescence in the green region upon irradiation with a mercury lamp (Figure B).…”

Hydration number: crucial role in nuclear magnetic relaxivity of Gd(III) chelate-based nanoparticles

“…The existence of three water molecules in PSS-Na[Gd· 2 ] colloids along with slow tumbling regime for Gd(III) centers determines the higher relaxation ability of the colloids and, hence, much higher sensitivity in contrasting. At the same time, nanoparticulate morphology represented herein is superior to conventional molecular contrast agents (CA) in terms of Gd 3+ leakage and hence toxicity towards cells and organs 18 . The obtained results reveal an impact of the macrocyclic platform bearing 1,3-diketonate chelating substituents, which both provide tight binding of the lanthanide ions via two chelating groups and prevent the inner sphere coordination of the third one.…”

“…Inclusion of Gd-chelates into hard nanoparticles is represented in literature by plenty of works due to its efficiency in slowing down rotational kinetics of Gd-chelates 13 – 21 . Transformation of non-covalently encapsulated Gd-chelates into hydrogels 13 or their silica coating 14 – 17 represents very efficient synthetic approaches of making efficient MR contrast agents, although more simple synthetic approach based on precipitation of ultra-small water insoluble Gd-based nanoparticles has been gained great attention in recent time 18 – 21 .…”

<p>A Chelate-Free Nano-Platform for Incorporation of Diagnostic and Therapeutic Isotopes</p>

“…These relaxometric changes are mainly due to the use of high concentration of metals for HIR process. Most of the metals used in these studies (eg, Tb, Eu, Sm, Y, Lu, Sr, Mo and Ba) [54][55][56][57][58][59][60][61][62] are strong paramagnetic and hence at these concentrations may affect both r 1 and r 2 measurements. However, in the case of radiolabelled FH NP for clinical diagnostic imaging, the concentration of the radiometal is usually in nano or even pico-M (eg, for labeling 92.5 MBq of 89 Zr, m Zr ≈ 6.25 pM).…”