Recent Advances in Luminescence Imaging of Biological Systems Using Lanthanide(III) Luminescent Complexes

The use of luminescence in biological systems allows one to diagnose diseases and understand cellular processes. Molecular systems, particularly lanthanide(III) complexes, have emerged as an attractive system for application in cellular luminescence imaging due to their long emission lifetimes, high brightness, possibility of controlling the spectroscopic properties at the molecular level, and tailoring of the ligand structure that adds sensing and therapeutic capabilities. This review aims to provide a background in luminescence imaging and lanthanide spectroscopy and discuss selected examples from the recent literature on lanthanide(III) luminescent complexes in cellular luminescence imaging, published in the period 2016-2020. Finally, the challenges and future directions that are pointing for the development of compounds that are capable of executing multiple functions and the use of light in regions where tissues and cells have low absorption will be discussed.

Fluorometric determination of ciprofloxacin using molecularly imprinted polymer and polystyrene microparticles doped with europium(III)(DBM)3phen

The authors describe a microparticle-based system for the detection of the fluoroquinolone antibiotic ciprofloxacin. The method is using the tris(dibenzoylmethane)(1,10-phenanthroline)europium(III) luminophore in polystyrene microparticles along with a molecularly imprinted polymer (MIP) for ciprofloxacin. If ciprofloxacin is captured by the MIP, it quenches the fluorescence of the luminophores. Fluorescence drops linearly in the 0.5-100 μg L^-1 ciprofloxacin concentration range, and the detection limit is 92 ng L^-1. The method was applied to the analysis of fish samples to assess the analytical performance of the probe. Recoveries ranged from 85.4 to 86.6%, and relative standard deviations between 2.1 and 3.9% (for n = 5). Graphical abstract Schematic presentation of a microparticle-based probe using the tris(dibenzoylmethane)(1,10-phenanthroline)europium(III) luminophore in polystyrene particles along with a molecularly imprinted polymer for ciprofloxacin. After removal of template, carboxylic groups left in the probe can bind to ciprofloxacin through hydrogen bonds.

Multifunctional Ionogels Incorporated with Lanthanide (Eu3+, Tb3+) Complexes Covalently Modified Multi-Walled Carbon Nanotubes

Ionogels refer to an emerging composite material made from the confinement of ionic liquids within some specific cross-linked network matrices. They have potential applications in areas such as electrochemical and optical-electric materials. Incorporation of lanthanide (Eu³⁺, Tb³⁺) complexes covalently functionalized multi-walled carbon nanotubes (MWCNTs) in ionogels provide new ideas to design and synthesize novel luminescent hybrid materials that have excellent characteristics of luminescence and ionic conductivity. Here, the multifunctional ionogels were synthesized by confining an ionic liquid and the rare earth functionalized MWCNTs in the cross-linked polymethyl methacrylate (PMMA) networks, resulting in a novel optical/electric multifunctional hybrid material. The SEM images and digital photographs suggest that the lanthanide functionalized MWCNTs are evenly dispersed in the hybrid matrices, thus leading to a certain transparency bulky gel. The resulting ionogels exhibit certain viscosity and flexibility, and display an intense red/green emission under UV-light irradiation. The intrinsic conductibility of the embedded ionic liquids and carbon nanotubes in conjunction with the outstanding photoluminescent properties of lanthanide complexes makes the soft hybrid gels a material with great potential and valuable application in the field of optical-electric materials.