Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses

Abstract

Different types of two-photon absorbing (TPA) fluorophores have been synthesized and specifically functionalized to be incorporated in the structure of phosphorus dendrimers (highly branched macromolecules). The TPA fluorophores were included in the periphery as terminal functions, in the core, or in the branches of the dendrimer structures, respectively. Also the functionalization in two compartments (core and surface, or branches and surface) was achieved. The consequences of the location of the fluorophores on the fluorescence and TPA properties have been studied. Several of these TPA fluorescent dendrimers have water-solubilizing functions as terminal groups, and fluorophores at the core or in the branches. They have been used as fluorescent tools in biology for different purposes, such as tracers for imaging blood vessels of living animals, for determining the phenotype of cells, for deciphering the mechanism of action of anticancer compounds, and for safer photodynamic therapy.

Two-Photon Absorbing Dendrimers and Their Properties—An Overview

“…Phosphorus dendrimers with chromophore units both at the core and at their periphery were also envisaged ( Figure 9 ) [ 52 ]. All these data were described in a recent review [ 53 ]. Some of these dendritic “nanodots” were shown to exhibit very high TPA cross-section values, outperforming those of quantum dots.…”

Phosphorus Dendrimers as Nanotools against Cancers

“…In order to ascertain the presence of the dendrimers in different compartment of the cells, a fluorescent analogue was synthesized, namely 4a-fluo-G 2 . This compound is a second generation dendrimer, bearing 12 highly fluorescent fluorophores at the level of the first generation, having two-photon absorption properties i.e., the ability to absorb simultaneously two photons of lower energy, compared to the classical absorption of one photon [ 52 ] ( Figure 6 ). In replacement of half of the pyridine-imine groups, PEG (polyethyleneglycol) derivatives were grafted as terminal functions to increase the solubility, which was decreased by the presence of the fluorophores, constituted of several aromatic groups.…”

Molecular and Coarse-Grained Modeling to Characterize and Optimize Dendrimer-Based Nanocarriers for Short Interfering RNA Delivery

“…To efficiently achieve intracellular delivery, siRNAs are usually complexed with cationic molecules which generate complexes with a size ranging from tens to a few hundreds of nanometers . Several polymeric and lipid nanocarriers have been developed in the literature, including chitosan, cationic lipids, polyethyleneimine, and dendrimers. − In the field of siRNA delivery, cationic phosphorous dendrimers − have proven to be excellent drug carriers for gene-silencing treatments after in vitro and in vivo experiments. ,,− In a previous study, we focused the attention on two different cationic phosphorus dendrimers of generation 3 for siRNA delivery . Those dendrimers were functionalized, respectively, with pyrrolidinium (DP) and morpholinium (DM) surface groups. , …”