Valeria Meli

Drug-Loaded Fluorescent Cubosomes: Versatile Nanoparticles for Potential Theranostic Applications

In this work, monoolein-based cubosomes were doped with two fluorescent probes, namely, fluorescein and dansyl, properly modified with a hydrocarbon chain to increase their encapsulation efficiency within the monoolein palisade. The same nanocarriers were also loaded with quercetin, a hydrophobic molecule with potential anticancer activity. Particularly, the cubosomes doped with the modified fluorescein probe were successfully exploited for single living cell imaging. The physicochemical and photophysical characterizations reported here, along with the well-known ability of cubosomes in hosting molecules with pharmaceutical interest, strongly encourage the use of these innovative fluorescent nanocarriers for theranostic purposes.

Cancer-cell-targeted theranostic cubosomes.

This work was devoted to the development of a new type of lipid-based (cubosome) theranostic nanoparticle able to simultaneously host camptothecin, a potent anticancer drug, and a squarain-based NIR-emitting fluorescent probe. Furthermore, to confer targeting abilities on these nanoparticles, they were dispersed using mixtures of Pluronic F108 and folate-conjugated Pluronic F108 in appropriate ratios. The physicochemical characterization, performed via SAXS, DLS, and cryo-TEM techniques, proved that aqueous dispersions of such cubosomes can be effectively prepared, while the photophysical characterization demonstrated that these nanoparticles may be used for in vivo imaging purposes. The superior ability of these innovative nanoparticles in targeting cancer cells was emphasized by investigating the lipid droplet alterations induced in HeLa cells upon exposure to targeted and nontargeted cubosomes.

Colorimetric response to anions by a "robust" copper(II) complex of a [9]aneN3 pendant arm derivative: CN- and I- selective sensing.

The 1 : 1 complex [Cu(L)](BF(4))(2)·MeCN (1) of the tetradentate ligand 1-(2-quinolinylmethyl)-1,4,7-triazacyclononane (L) selectively changes its colour in the presence of CN(-) in H(2)O and MeCN (without undergoing decomplexation from the macrocyclic ligand). The same complex in MeCN assumes different colours in the presence of CN(-) or I(-).

Docetaxel-Loaded Fluorescent Liquid-Crystalline Nanoparticles for Cancer Theranostics

Here, we describe a novel monoolein-based cubosome formulation engineered for possible theranostic applications in oncology. The Docetaxel-loaded nanoparticles were stabilized in water by a mixture of commercial Pluronic (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer) F108 (PF108) and rhodamine- and folate-conjugated PF108 so that the nanoparticles possess targeting, therapeutic, and imaging properties. Nanoparticles were investigated by DLS, cryo-TEM, and SAXS to confirm their structural features. The fluorescent emission characterization of the proposed formulation indicated that the rhodamine conjugated to the PF108 experiences an environment less polar than water (similar to chloroform), suggesting that the fluorescent fragment is buried within the poly(ethylene oxide) corona surrounding the nanoparticle. Furthermore, these nanoparticles were successfully used to image living HeLa cells and demonstrated a significant short-term (4 h incubation) cytotoxicity effect against these cancer cells. Furthermore, given their analogy as nanocarriers for molecules of pharmaceutical interest and to better stress the singularities of these bicontinuous cubic nanoparticles, we also quantitatively evaluated the differences between cubosomes and multilamellar liposomes in terms of surface area and hydrophobic volume.

Cubosome formulations stabilized by a dansyl-conjugated block copolymer for possible nanomedicine applications

We present here an innovative, fluorescent, monoolein-based cubosome dispersion. Rather than embedded within the monoolein palisade, the fluorescent imaging agent, namely dansyl, was conjugated to the terminal ethylene oxide moieties of the block copolymer Pluronic F108. We discuss the physicochemical and photophysical properties of this fluorescent Pluronic and of a cubosome formulation stabilized by a mixture of dansyl-conjugated and non-conjugated Pluronic, also including an anticancer drug (quercetin). Furthermore, we performed biocompatibility tests against HeLa cells to assess internalization and cytotoxicity features of this nanoparticles aqueous dispersion. Cryo-TEM, SAXS, and DLS analysis, proved the bicontinuous cubic inner nanostructure and the morphology of this fluorescent cubosome dispersion, while photophysical measurements and biocompatibility results basically validate their potential use for theranostic nanomedicine applications.

Effects of monoolein-based cubosome formulations on lipid droplets and mitochondria of HeLa cells

Despite the remarkable development of nanoparticles for different purposes, relatively little is known about their interaction with biological systems and individual cells. Here the effects of two monoolein-based cubosome formulations stabilized by Pluronic F108 and F127 were investigated against HeLa cells. Microscopy analysis on living cells loaded with organelle-specific fluorescent probes was performed to assess the formation of cytoplasmic lipid droplets after nanoparticle treatment. Mitochondrial membrane potential and mitochondrial ROS generation were also investigated in relation to the capability of the accumulated lipids to affect mitochondrial functions. Values of the main cellular unsaturated fatty acids were also measured to assess cell lipid profile modulation. Results from this study show that the uptake of both cubosome formulations induced modification of the cell lipid profile, lipid droplet accumulation, mitochondrial hyperpolarization and mitochondrial ROS generation. These results shed some light on the influence exerted by monoolein-based cubosome formulations on subcellular organelles and their possible adverse effects on cell functions.

Solvatochromic fluorescent BODIPY derivative as imaging agent in camptothecin loaded hexosomes for possible theranostic applications

We here discuss the potential theranostic nanomedicine application of an innovative formulation consisting of monoolein-based nanoparticles with a two-dimensional hexagonal inner structure stabilized in water using a mixture of PEO132–PPO50–PEO132 block copolymers with and without conjugated folate for targeting. The proposed tumor-cell targeted formulation was shown to be able to simultaneously host the model anticancer drug camptothecin and a pyrene-modified BODIPY fluorophore, based on dynamic light scattering, small-angle X-ray scattering, and cryogenic transmission electron microscopy. The photophysical properties of the fluorophore were studied in solution in various solvents. A marked fluorescent solvatochromism, whose origin was explained by time-dependent density functional theory theoretical calculations, was observed. Fluorescence microscopy showed that HeLa cells readily internalize these nanoparticles, and that the fluorophore localizes within the lipid droplets. In addition, cytotoxicity test revealed that these nanoparticles are not toxic at the concentration used for the imaging analysis.

Monoolein-based cubosomes affect lipid profile in HeLa cells

Monoolein-based cubosomes are promising drug delivery nanocarriers for theranostic purposes. Nevertheless, a small amount of research has been undertaken to investigate the impact of these biocompatible nanoparticles on cell lipid profile. The purpose of the present investigation was to explore changes in lipid components occurring in human carcinoma HeLa cells when exposed to short-term treatments (2 and 4h) with monoolein-based cubosomes stabilized by Pluronic F108 (MO/PF108). A combination of TLC and reversed-phase HPLC with DAD and ELSD detection was performed to analyze cell total fatty acid profile and levels of phospholipids, free cholesterol, triacylglycerols, and cholesteryl esters. The treatments with MO/PF108 cubosomes, at non-cytotoxic concentration (83μg/mL of MO), affected HeLa fatty acid profile, and a significant increase in the level of oleic acid 18:1 n-9 was observed in treated cells after lipid component saponification. Nanoparticle uptake modulated HeLa cell lipid composition, inducing a remarkable incorporation of oleic acid in the phospholipid and triacylglycerol fractions, whereas no changes were observed in the cellular levels of free cholesterol and cholesteryl oleate. Moreover, cell-based fluorescent measurements of intracellular membranes and lipid droplet content were assessed on cubosome-treated cells with an alternative technique using Nile red staining. A significant increase in the amount of the intracellular membranes and mostly in the cytoplasmic lipid droplets was detected, confirming that monoolein-based cubosome treatment influences the synthesis of intracellular membranes and accumulation of lipid droplets.

Cubosomes for in vivo fluorescence lifetime imaging

Herein we provided the first proof of principle for in vivo fluorescence optical imaging application using monoolein-based cubosomes in a healthy mouse animal model. This formulation, administered at a non-cytotoxic concentration, was capable of providing both exogenous contrast for NIR fluorescence imaging with very high efficiency and chemospecific information upon lifetime analysis. Time-resolved measurements of fluorescence after the intravenous injection of cubosomes revealed that the dye rapidly accumulated mainly in the liver, while lifetimes profiles obtained in vivo allowed for discriminating between free dye or dye embedded within the cubosome nanostructure after injection.

An OFF–ON chemosensor for biological and environmental applications: sensing Cd2+ in water using catanionic vesicles and in living cells

A new OFF-ON fluorescent chemosensor (L(1)) for Cd(2+) recognition based on a 5-chloro-8-hydroxyquinoline pendant arm derivative of 1,4,7-triazacyclononane ([9]aneN3) will be presented and its photochemical features in an MeCN-H2O 1 : 1 (v/v) mixture, in pure water, after inclusion within catanionic vesicles, and in living cells will be discussed. The coordination properties of L(1) both in solution and in the solid state were preliminarily studied and its selectivity towards Cd(2+)versus a set of different metal ions (Cu(2+), Zn(2+), Cd(2+), Pb(2+), Al(3+), Hg(2+), Co(2+), Ni(2+), Mn(2+), Mg(2+), K(+), Ca(2+), Ag(+), and Na(+)) was verified in MeCN-H2O 1 : 1 (v/v). In water, upon addition of increasing amounts of Cd(2+) to L(1) an enhancement of the fluorescence emission was detected. To overcome this serious drawback, L(1) was dissolved in an innovative catanionic vesicular solution based on sodium bis(2-ethylhexyl) sulfosuccinate, a traditional surfactant, and 1-dodecyl-3-methylimidazolium bromide, an ionic liquid. When enclosed within the vesicle bilayers in water, L(1) restored its fluorescence emission property upon addition of Cd(2+). Remarkably, L(1) enters the cellular membrane of living cells thus allowing the detection of intracellular Cd(2+). These findings encourage the application of this new fluorescent chemosensor in real samples for histological and environmental analyses.