Polyphosphoester-stabilized cubosomes encapsulating a Ru(II) complex for the photodynamic treatment of lung adenocarcinoma.

The clinical translation of photosensitizers based on ruthenium(II) polypyridyl complexes (RPCs) in photodynamic therapy of cancer faces several challenges. To address these limitations, we conducted an investigation to assess the potential of a cubosome formulation stabilized in water against coalescence utilizing a polyphosphoester analog of Pluronic F127 as a stabilizer and loaded with newly synthesized RPC-based photosensitizer [Ru(dppn)2(bpy-morph)](PF6)2 (bpy-morph = 2,2'-bipyridine-4,4'-diylbis(morpholinomethanone)), PS-Ru. The photophysical characterization of PS-Ru revealed its robust capacity to induce the formation of singlet oxygen (1O2). Furthermore, the physicochemical analysis of the PS-Ru-loaded cubosomes dispersion demonstrated that the encapsulation of the photosensitizer within the nanoparticles did not disrupt the three-dimensional arrangement of the lipid bilayer. The biological tests showed that PS-Ru-loaded cubosomes exhibited significant phototoxic activity when exposed to the light source, in stark contrast to empty cubosomes and to the same formulation without irradiation. This promising outcome suggests the potential of the formulation in overcoming the drawbacks associated with the clinical use of RPCs in photodynamic therapy for anticancer treatments.

Role of the Solvent in the Reactivity of Bis-4-imidazoline-2-selone Derivatives toward I2: An Experimental and Theoretical Approach.

The reactivity of 1,1'-bis(3-methyl-4-imidazolin-2-selone)methane (L1) and 1,2-bis(3-methyl-4-imidazolin-2-selone)ethane (L2) toward I2 has been explored in MeCN under different experimental conditions and compared with that in CH2Cl2. The compounds [L1'](I)2 (I), [L1I]n(I)n (II), [L1(µ-Se)](I)2·1/2H2O (III), [L1I](I3)·2I2 (IV), and [L2](I)2·MeCN (V) were obtained and characterized. X-ray diffraction analyses point out an ionic nature for these compounds, which is presumably favored by the polarity of the solvent used. In particular, [L1I]n(I)n (II) represents the first example of an iodonium complex of imidazoline-2-selone derivatives, while [L1(µ-Se)](I)2·1/2H2O (III) represents a unique example of a dicationic [RSeSeSeR] triselane. Density functional theory calculations have allowed us to better understand the nature of the obtained compounds and to justify their formations in polarizing reaction conditions rather than in low polar solvents.

Potential of curcumin-loaded cubosomes for topical treatment of cervical cancer.

Cervical cancer is one of the most common cancers affecting women worldwide. There are an estimated 570.000 new cases of cervical cancer each year and conventional treatments can cause severe side effects. In this work, we developed a platform for vaginal administration of lipophilic drugs for cervical cancer treatment. We formulated mucoadhesive cubosomes for the delivery of curcumin, a lipophilic drug for cervical cancer treatment, to increase its bioavailability and local absorption. This study tests the use of cubosomes for vaginal drug administration and assesses their potential efficiency using the CAM (chick embryo chorioallantoic membrane) model. SAXS (small-angle X-ray scattering), cryo-TEM (cryo-transmission electron microscopy), and dynamic light scattering (DLS) were employed to characterise the system. With ex vivo permeation and retention studies, we find that the curcumin released from our system is retained in the vaginal mucosa. In vitro cytotoxicity assay and cellular uptake showed an increased cytotoxic effect of curcumin against HeLa cell line when incorporated into the cubosomes. The curcumin-loaded cubosomes also demonstrated an antiangiogenic effect evaluated in vivo by the CAM model.

Study of the DNA binding mechanism and in vitro activity against cancer cells of iron(III) and aluminium(III) kojic acid derivative complexes.

Metal ions have unique electrochemical and spectroscopical properties that cannot be attained by purely organic compounds. Most of the metal ions are toxic to humans, but paradoxically, metallodrugs are used in medicine as therapeutics and theranostics. Metallodrugs are eliminated in urine and faeces, and therefore release toxic metals and ligands into aquatic ecosystems, thereby raising concerns regarding environmental risks. The use of metallodrugs based on essential metal ions (i.e., iron, copper and zinc), instead of toxic ions, is a new alternative with minor hazards. Kojic acid is an Asperigillus oryzae metabolite of low toxicity used in the food and cosmetics industries. Its derivatives form stable complexes with iron(III) ions, which bind effectively to DNA and inhibit DNA polymerization. The iron(III)/S2 ligand complexes reduce in vitro colon carcinoma (Caco2) cell viability and significantly decrease the cell number. The kojic acid derivative complexes with iron(III) presented here are an alternative to the currently used platinum complexes in cancer therapy.

In Vitro Evaluation of Nanoerythrosome Cytotoxicity and Uptake in Pancreatic Endothelial Cells: Implications for ß-Cell Imaging Applications.

Biomolecule-targeted imaging represents one of the most difficult challenges in medicine. Nanoerythrosomes (NERs) are nanovesicles obtained after lysis of red blood cells, and they are promising tools for drug delivery and imaging. In this work, a formulation based on NERs functionalized with 7-amino-3-methylcoumarin via cross-linking was tested on rat INS-1E and mouse MIN6 ß-cells and endothelial MSI cell lines. First, the morphology, size, ζ-potentials, and spectroscopic properties of the aggregates were investigated, highlighting that the functionalization did not significantly affect the nanoparticles' physicochemical features. In vitro, the nanoparticles did not significantly affect the proliferation and function of INS-1E and MIN6 ß-cells at different concentrations. Only at the highest concentration tested on the MSI cell line, the formulation inhibited proliferation. Furthermore, NER aggregates were not internalized in both INS-1E and MIN6 cell lines, while a diffuse fluorescence was noticed in the cytosol of the MSI cell line at the highest concentrations. These findings proved that NER formulations might represent a new nanotool for ß-cell imaging as a part of a strategy aimed to prevent any intracellular accumulation, thus reducing/avoiding side effects.

Hybrid Theranostic Cubosomes for Efficient NIR-Induced Photodynamic Therapy.

In recent years, lipid bicontinuous cubic liquid-crystalline nanoparticles known as cubosomes have been under investigation because of their favorable properties as drug nanocarriers useful for anticancer treatments. Herein, we present organic/inorganic hybrid, theranostic cubosomes stabilized in water with a shell of alternate layers of chitosan, single strand DNA (model genetic material for potential gene therapy), and folic acid-chitosan conjugate (the outmost layer), coencapsulating up-converting Er3+ and Yb3+ codoped NaYF4 nanoparticles and daunorubicin. The latter acts as a chemotherapeutic drug of photosensitizing activity, while up-converting nanoparticles serve as energy harvester and diagnostic agent. Cellular uptake and NIR-induced photodynamic therapy were evaluated in vitro against human skin melanoma (MeWo) and ovarian (SKOV-3) cancer cells. Results evidenced the preferential uptake of the theranostic cubosomes in SKOV-3 cells in comparison to uptake in MeWo cells, and this effect was enhanced by the folic acid functionalization of the cubosomes surface. Nanocarriers coloaded with the hybrid fluorophores exhibited a superior NIR-induced photodynamic activity, also confirmed by the improved mitochondrial activity and the most affecting f-actin fibers of cytoskeleton. Similar results, but with higher photocytotoxicity, were detected when folic acid-functionalized cubosomes were incubated with SKOV-3 cells. Taken on the whole, these results prove these hybrid cubosomes are good candidates for the photodynamic treatment of tumor lesions.

Lipid vesicular gels for topical administration of antioxidants.

The application of a formulation on the skin represents an effective way to deliver bio-active molecules for therapeutical purposes. Moreover, the outermost skin layer, the stratum corneum, can be overcome by employing chemical permeation enhancers and edge activators as components. Several lipids can be considered as permeation enhancers, such as the ubiquitous monoolein, one of the most used building blocks for the preparation of lipid liquid crystalline nanoparticles which are applied as drug carriers for nanomedicine applications. Recent papers highlighted how bile salts can affect the phase behavior of monoolein to obtain drug carriers suitable for topical administration, given their role as edge activators into the formulation. Herein, the encapsulation of natural antioxidants (caffeic acid and ferulic acid) into lipid vesicular gels (LVGs) made by monoolein and sodium taurocholate (TC) in water was studied to produce formulations suitable for topical application. TC induces a bicontinuous cubic to multilamellar phase transition for monoolein in water at the given concentrations, and by increasing its content into the formulations, unilamellar LVGs are formed. The encapsulation of the two antioxidants did not affect significantly the structure of the gels. The oscillating rheological studies showed that ferulic acid has a structuring effect on the lipid matrix, in comparison with the empty dispersion and the one containing caffeic acid. These gels were then tested in vitro on new-born pig skin to evaluate their efficacy as drug carriers for topical administration, showing that caffeic acid is mostly retained in the gel whereas ferulic acid is released at a higher degree. The data herein reported provide some further information on the effect of bile salts on the lipid self-assembly to evaluate useful compositions for topical administration of natural antioxidants.

Understanding the self-assembly of the polymeric drug solubilizer Soluplus®.

HYPOTHESIS: Soluplus® is one of the most widely used amphiphilic copolymers in drug delivery and has been reported to strongly enhance the adsorption of model drugs. However, there is still a limited understanding of its micellar behavior as it responds to the different routes of administration, which involve important changes in concentration. EXPERIMENTS: The microstructure of Soluplus aqueous solutions has been investigated at a wide range of polymer concentrations (2 × 10-6 - 0.2 g/mL) by a combination of diffusion NMR (dNMR), small angle X-ray scattering (SAXS), static (SLS) dynamic (DLS) light scattering and viscosity measurements. These techniques have been coupled with surface tension measurements to frame the polymer's critical micellar concentration (cmc). FINDINGS: We demonstrate the presence at all tested concentrations of two forms of Soluplus, with hydrodynamic radii of 3 and 26 nm, where the fraction of smaller objects accounts for as much as 60-70%. dNMR, SAXS, DLS and SLS indicate that Soluplus spontaneously self-assembles into large spherical particles with a core-shell structure. However, self-assembly takes place three orders of magnitude above the cmc evaluated via surface tension measurements. Instead of the traditional cooperative micellization process, we propose a thermal-activated isodesmic self-assembly of the small aggregates into core-shell micelles.

Improving Dermal Delivery of Rose Bengal by Deformable Lipid Nanovesicles for Topical Treatment of Melanoma.

Cutaneous melanoma is one of the most aggressive and metastatic forms of skin cancer. However, current therapeutic options present several limitations, and the annual death rate due to melanoma increases every year. Dermal delivery of nanomedicines can effectively eradicate primary melanoma lesions, avoid the metastatic process, and improve survival. Rose Bengal (RB) is a sono-photosensitizer drug with intrinsic cytotoxicity toward melanoma without external stimuli but the biopharmaceutical profile limits its clinical use. Here, we propose deformable lipid nanovesicles, also known as transfersomes (TF), for the targeted dermal delivery of RB to melanoma lesions to eradicate them in the absence of external stimuli. Considering RB's poor ability to cross the stratum corneum and its photosensitizer nature, transfersomal carriers were selected simultaneously to enhance RB penetration to the deepest skin layers and protect RB from undesired photodegradation. RB-loaded TF dispersion (RB-TF), prepared by a modified reverse-phase evaporation method, were nanosized with a ζ-potential value below -30 mV. The spectrophotometric and fluorimetric analysis revealed that RB efficiently interacted with the lipid phase. The morphological investigations (transmission electron microscopy and small-angle X-ray scattering) proved that RB intercalated within the phospholipid bilayer of TF originating unilamellar and deformable vesicles, in contrast to the rigid multilamellar unloaded ones. Such outcomes agree with the results of the in vitro permeation study, where the lack of a burst RB permeation peak for RB-TF, observed instead for the free drug, suggests that a significant amount of RB interacted with lipid nanovesicles. Also, RB-TF proved to protect RB from undesired photodegradation over 24 h of direct light exposure. The ex vivo epidermis permeation study proved that RB-TF significantly increased RB's amount permeating the epidermis compared to the free drug (78.31 vs 38.31%). Finally, the antiproliferative assays on melanoma cells suggested that RB-TF effectively reduced cell growth compared to free RB at the concentrations tested (25 and 50 µM). RB-TF could potentially increase selectivity toward cancer cells. Considering the outcomes of the characterization and cytotoxicity studies performed on RB-TF, we conclude that RB-TF represents a valid potential alternative tool to fight against primary melanoma lesions via dermal delivery in the absence of light.

Rational Design of Sustainable Liquid Microcapsules for Spontaneous Fragrance Encapsulation.

The high volatility, water-immiscibility, and light/oxygen-sensitivity of most aroma compounds represent a challenge to their incorporation in liquid consumer products. Current encapsulation methods entail the use of petroleum-based materials, initiators, and crosslinkers as well as mixing, heating, and purification steps. Hence, more efficient and eco-friendly approaches to encapsulation must be sought. Herein, we propose a simple method by making use of a pre-formed amphiphilic polymer and employing the Hansen Solubility Parameters approach to determine which fragrances could be encapsulated by spontaneous coacervation in water. The coacervates do not precipitate as solids but they remain suspended as colloidally stable liquid microcapsules, as demonstrated by fluorescence correlation spectroscopy. The effective encapsulation of fragrance is proven through confocal Raman spectroscopy, while the structure of the capsules is investigated by means of cryo FIB/SEM, confocal laser scanning microscopy, and small-angle X-ray scattering.

Kojic acid derivatives as double face ligands for metal and phosphate ions.

A family of combined Kojic acid and polyamine derivatives has been synthesized as phosphate anion and metal ion ligands. The stoichiometry, stability and structure of the ion/ligand adducts were determined by 1H NMR spectroscopy, potentiometry, EXAFS and DFT calculations. The presented dual ligands bind effectively both phosphate anions and metal ions and could be used as effective ion receptors in challenging water conditions in the broad pH range. A careful analysis of the heatmaps of the stability constants allows to choose the most appropriate ligand for the ion for qualitative and/or quantitative analysis in water, without analyte pre-treatment. Extremely high-water solubility (>0.6 M) and ion(s)/ligand stability of the adducts in the pH 3-11 are the greatest advantages of the presented here molecules over other known ion sensors. The presented here molecules represent an innovative class of dual metal/anion ligands, with perspective of medical and environmental use.

Bicontinuous cubic liquid crystalline phase nanoparticles stabilized by softwood hemicellulose.

The colloidal stability of lipid based cubosomes, aqueous dispersion of inverse bicontinuous cubic phase, can be significantly increased by a stabilizer. The most commonly used stabilizers are non-ionic tri-block copolymers, poloxamers, which adsorb at the lipid-water interface and hence sterically stabilize the dispersion. One of the challenges with these synthetic polymers is the effect on the internal structure of the cubosomes and the potential toxicity when these nanoparticles are applied as nanomedicine platforms. The natural polysaccharide, softwood hemicellulose, has been proved to be an excellent stabilizer for oil-in-water emulsions, partially due to the presence of hydrophobic lignin in the extract which to some extent is associated to hemicellulose. Herein, we reported for the first time cubosomes stabilized by two types of softwood hemicelluloses, where one is extracted through thermomechanical pulping (TMP, low lignin content) and the other obtained from sodium-based sulfite liquor (SSL, high lignin content). The effect of the two hemicellulose samples on the colloidal stability and structure of monoolein-based cubosomes have been investigated via DLS, SAXS, AFM and cryo-TEM. The data obtained suggest that both types of the hemicelluloses stabilize monoolein (GMO) based cubosomes in water without significantly affecting their size, morphology and inner structure. SSL-extracted hemicellulose yields the most stable cubosomes, likely due to the higher content of lignin in comparison to TMP-stabilized ones. In addition, the stability of these particles was tested under physiological conditions relevant to possible application as drug carriers.

Bioimaging Applications of Non-Lamellar Liquid Crystalline Nanoparticles.

Self-assembling processes of amphiphilic lipids in water give rise to complex architectures known as lyotropic liquid crystalline (LLC) phases. Particularly, bicontinuous cubic and hexagonal LLC phases can be dispersed in water forming colloidal nanoparticles respectively known as cubosomes and hexosomes. These non-lamellar LLC dispersions are of particular interest for pharmaceutical and biomedical applications as they are potentially non-toxic, chemically stable, and biocompatible, also allowing encapsulation of large amounts of drugs. Furthermore, conjugation of specific moieties enables their targeting, increasing therapeutic efficacies and reducing side effects by avoiding exposure of healthy tissues. In addition, as they can be easy loaded or functionalized with both hydrophobic and hydrophilic imaging probes, cubosomes and hexosomes can be used for the engineering of multifunctional/theranostic nanoplatforms. This review outlines recent advances in the applications of cubosomes and hexosomes for in vitro and in vivo bioimaging.

Tuning lipid structure by bile salts: Hexosomes for topical administration of catechin.

The delivery of bio-active molecules through the skin is challenging given the complex structure of its outer layer, the stratum corneum. Here we explore the possibility to encapsulate natural compounds into nanocarriers containing permeation enhancers that can affect the fluidity of the stratum corneum lipids. This approach is expected to facilitate dermal or transdermal release. For this purpose, the application of bile salts, which are natural surfactants involved in vivo in lipid digestion, was exploited. Bile salts were added to lipid liquid crystalline nanoparticles (NPs) made of monoolein for antioxidant topical delivery. Monoolein self-assembly behaviour in water was affected by the presence of bile salts molecules, giving a transition from a bicontinuous cubic to unilamellar vesicles dispersion. By adding oleic acid (OA), the change of curvature in the system led to a reverse hexagonal phase. The morphology, structure and size of the nanocarriers was investigated before the nanoparticles were loaded with catechin, a natural antioxidant occurring in plants and food. The encapsulation did not affect significantly the formulation phase behaviour. The formulation loaded with bile salts and catechin was thereafter tested in vitro on the skin from new-born pig. The results for two different lipid formulations without bile salts were compared under the same experimental conditions and with the same antioxidant. The formulation with bile salts showed the best performance, allowing a superior permeation of catechin in the different skin layers in comparison with formulations without bile salt.

Surface-modified nanoerythrosomes for potential optical imaging diagnostics.

Nanoerythrosomes (NERs), vesicle-like nanoparticles derived from red blood cells, represent a new and interesting vector for therapeutic molecules and imaging probes, mainly thanks to their high stability and excellent biocompatibility. Aiming to present a proof-of-concept of the use of NERs as diagnostic tools for in vitro/in vivo imaging purposes, we report here several functionalization routes to decorate the surfaces of NERs derived from bovine blood with two different fluorophores: 7-amino-4-methylcumarin and dibenzocyclooctinecyanine5.5. Notably, the fluorophores were cross-linked to the NERs surface with glutaraldehyde and, in the case of dibenzocyclooctinecyanine5.5, also using a click-chemistry route, termed strain-promoted azide-alkyne cycloaddition. The physicochemical characterization highlighted the high stability of the NERs derivatives in physiological conditions. Furthermore, the loading efficiency of the fluorophores on the NERs surface was evaluated using both UV-Vis spectroscopy and fluorescence microscopy.

Cubosomes stabilized by a polyphosphoester-analog of Pluronic F127 with reduced cytotoxicity.

Lyotropic liquid crystalline nanoparticles with bicontinuous cubic internal nanostructure, known as cubosomes, have been proposed as nanocarriers in various medical applications. However, as these nanoparticles show a certain degree of cytotoxicity, particularly against erythrocytes, their application in systemic administrations is limited to date. Intending to produce a more biocompatible formulation, we prepared cubosomes for the first time stabilized with a biodegradable polyphosphoester-analog of the commonly used Pluronic F127. The ABA-triblock copolymer poly(methyl ethylene phosphate)-block-poly(propylene oxide)-block-poly(methyl ethylene phosphate) (PMEP-b-PPO-b-PMEP) was prepared by organocatalyzed ring-opening polymerization of MEP. The cytotoxic features of the resulting formulation were investigated against two different cell lines (HEK-293 and HUVEC) and human red blood cells. The response of the complement system was also evaluated. Results proved the poly(phosphoester)-based formulation was significantly less toxic than that prepared using Pluronic F127 with respect to all the tested cell lines and, more importantly, hemolysis assay and complement system activation tests demonstrated its very high hemocompatibility. The potentially biodegradable poly(phosphoester)-based cubosomes represent a new and versatile platform for preparation of functional and smart nanocarriers.

Halogenated isophthalamides and dipicolineamides: the role of the halogen substituents in the anion binding properties.

A novel family of amide-based receptors is herein described. Specifically, the role of the halogen substituents at the aryl moieties in the anion binding properties of a series of halogenated isophthalamides and dipicolineamides (L1-L6) was investigated both in solution and in the solid state in order to evaluate the incidence of all possible different and combined weak host-guest interactions. Only L5 and L6 bearing pentafluorophenyl rings as substituents have some affinities for the set of anions studied. In particular, in the case of L5 an interesting behaviour with the formation of a non-symmetric adduct with benzoate and dihydrogen phosphate was hypothesised by 1H- and 19F-NMR spectroscopy studies in solution and confirmed by theoretical calculation. The study of the crystal structures of the receptors demonstrated that the steric hindrance determined by the halogen substituents in the receptor molecules influences the accessibility of the anions to the isophthalamide or dipicoline amide NH moieties, thus modulating the affinity for the anion guests.

Tuning the Encapsulation of Simple Fragrances with an Amphiphilic Graft Copolymer.

The encapsulation of poorly water-soluble compounds such as perfumes, flavors, and bioactive molecules is a key step in the formulation of a large variety of consumer products in the fields of household care and personal care. We study the encapsulation ability of an amphiphilic poly(ethylene glycol)-graft-poly(vinyl acetate) (PEG-g-PVAc) graft copolymer, extending the focus to the entire phase diagram of polymer/perfume/water systems with three common natural fragrances. The three perfume molecules (2-phenyl ethanol, L-carvone, and α-pinene) possess different water affinities, as expressed by their octanol/water partition coefficients. The investigation of the polymorphism of PEG-g-PVAc in these systems is carried out by means of dynamic light scattering, small-angle X-ray scattering, NMR spectroscopy, and confocal laser scanning microscopy. The results presented here demonstrate that the choice of fragrance can dramatically affect the supramolecular structures formed by the polymer in aqueous solution, with important consequences on formulations of industrial interest such as the demixing of complex perfume blends when one or more of the components have no chemical affinity for any of the polymer blocks.

Multifunctional cubic liquid crystalline nanoparticles for chemo- and photodynamic synergistic cancer therapy.

With the aim of engineering multifunctional nanoparticles useful for cancer therapy, a diketopyrrolopyrrole-porphyrin based photosensitizer was here conjugated to a block copolymer (Pluronic F108), and used to stabilize in water lipidic cubic liquid crystalline nanoparticles (cubosomes), also loaded with the antineoplastic agent docetaxel. The physicochemical characterization by SAXS, DLS, and cryo-TEM demonstrated that the formulation consisted of cubosomes, about 150 nm in size, possessing a bicontinuous cubic structure (space group Pn3m). The cellular imaging experiments proved that these nanoparticles localized in lysosomes and mitochondria, while cytotoxicity tests evidenced a slight but significant synergistic effect which, after irradiation, increased the toxicity induced by docetaxel alone, allowing further reduction of cell viability.

Branched alkyldimethylamine oxide surfactants: An effective strategy for the design of high concentration/low viscosity surfactant formulations.

HYPOTHESIS: The rational design of branched-tail surfactants is a suitable strategy to obtain low-viscosity surfactant-rich isotropic aqueous mixtures with negligible effects on biodegradability. This opens a way to the design of concentrated ("water-free") surfactant formulations, highly attractive for their ecological and economic benefits. EXPERIMENTS: The aggregation behaviour of N,N-dimethyl-2-propylheptan-1-amine oxide (C10DAO-branched) in aqueous mixtures is investigated across the entire composition range by polarized optical microscopy, small angle X-ray and neutron scattering, electron paramagnetic resonance, and pulse-gradient stimulated echo nuclear magnetic resonance. The humidity scanning quartz crystal microbalance with dissipation monitoring technique is validated as a tool for the fast screening of surfactants phase behaviour. Furthermore, the shear viscosities and viscoelastic moduli of the systems are determined by rheological measurements. FINDINGS: With respect to the linear isomer, C10DAO-branched presents a much lower tendency to form lyotropic liquid crystalline phases. Except for a narrow composition and temperature range in which a lamellar structure is observed, C10DAO-branched aqueous mixtures are isotropic liquids whose microstructure changes, with increasing concentration, from micellar solutions to unstructured dispersions of hydrated surfactant molecules. Low-viscosity was found for all these mixtures, including the most concentrated ones. Thus, the introduction of a single short side-chain in the tail is demonstrated to be an effective approach to increase the active concentration in surfactant formulations.