Lipid based liquid-crystalline stabilized formulations for the sustained release of bioactive hydrophilic molecules.

Lipid based formulations, endowed of long term stability as a result of the formation of lamellar liquid crystals, were prepared using the natural lipids lecithin and glycerol trioleate in water, and characterized using optical microscopy, SAXRD and NMR. The formulations, designed as possible carriers for lysozyme and caffeine, were evaluated for structural features and stability after the loading of the guest molecules. Release experiments were performed at 37 °C using the PBS medium.

Purification, Conformational Analysis, and Properties of a Family of Tigerinin Peptides from Skin Secretions of the Crowned Bullfrog Hoplobatrachus occipitalis.

Four host-defense peptides belonging to the tigerinin family (tigerinin-1O: RICTPIPFPMCY; tigerinin-2O: RTCIPIPLVMC; tigerinin-3O: RICTAIPLPMCL; and tigerinin-4O: RTCIPIPPVCF) were isolated from skin secretions of the African crowned bullfrog Hoplobatrachus occipitalis. In aqueous solution at pH 4.8, the cyclic domain of tigerinin-2O adopts a rigid amphipathic conformation that incorporates a flexible N-terminal tail.

Improvement of quercetin protective effect against oxidative stress skin damages by incorporation in nanovesicles.

Quercetin was incorporated in glycerosomes, new phospholipid-glycerol vesicles, and their protective effect against oxidative stress skin damages was extensively evaluated. In particular, the concentration-dependent effect of glycerol (from 10 to 50%) on vesicle suitability as cutaneous carriers of quercetin was carefully assessed. All vesicles were unilamellar and small in size (∼80-110 nm), as confirmed by cryo-TEM observation, with a drug incorporation efficiency ranging between 81 and 91%.

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.

Molecular arrangements and interconnected bilayer formation induced by alcohol or polyalcohol in phospholipid vesicles.

A self-assembled hybrid phospholipid vesicular system containing various penetration enhancers - ethanol, Transcutol and propylenglycol - was prepared and characterized. The effects of the different alcohol or polyalcohols structure and their concentration on the features of the assembled vesicles were evaluated using a combination of different techniques, including cryo-transmission electron microscopy, laser light scattering, differential scanning calorimetry, small- and wide-angle X-ray scattering and rheological analysis. These techniques allow explaining the structural rearrangements of the bilayer assembly due to the alcohol or polyalcohol addition.

From self-assembly fundamental knowledge to nanomedicine developments.

This review highlights the key role of NMR techniques in demonstrating the molecular aspects of the self-assembly of surfactant molecules that nowadays constitute the basic knowledge which modern nanoscience relies on. The aim is to provide a tutorial overview. The story of a rigorous scientific approach to understand self-assembly in surfactant systems and biological membranes starts in the early seventies when the progresses of SAXRD and NMR technological facilities allowed to demonstrate the existence of ordered soft matter, and the validity of Tanford approach concerning self-assembly at a molecular level.

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.

Effect of diclofenac and glycol intercalation on structural assembly of phospholipid lamellar vesicles.

The aim of the current study was to improve the knowledge of drug-glycol-phospholipid-interactions and their effects in lamellar vesicle suitability as drug delivery systems. Liposomes were prepared using hydrogenated soy phosphatidylcholine (P90H, 60 mg/ml) and diclofenac sodium salt at two concentrations (5-10 mg/ml). To obtain innovative vesicles two permeation enhancers with glycol group, diethyleneglycol monoethyl ether and propylene glycol, were added to the water phase at different ratios (5%, 10%, and 20%).

Close-packed vesicles for diclofenac skin delivery and fibroblast targeting.

Concentrated and interconnected penetration enhancer containing vesicles (PEVs) are proposed as carriers for dermal delivery of diclofenac. PEVs were prepared by using a commercial phosphatidylcholine mixture (180 mg/m) and transcutol in different amounts. Conventional liposomes were also prepared and tested as control.

Nanocarriers for antioxidant resveratrol: formulation approach, vesicle self-assembly and stability evaluation.

In this work we studied various nanoformulations of resveratrol in phospholipid vesicles. Conventional phophatidylcholine liposomes were prepared and characterized in parallel with PEVs (Penetration Enhancer-containing Vesicles) obtained by adding one of eight selected amphiphilic penetration enhancers (PEs; 0.2% w/v; HLB range 1-16) to the composition.

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.

Physicochemical, cytotoxic, and dermal release features of a novel cationic liposome nanocarrier.

A novel cationic liposome nanocarrier, having interesting performance in topical drug delivery, is here presented and evaluated for its features. Two penetration enhancers, namely monoolein and lauroylcholine chloride, are combined to rapidly formulate (15 min) a cationic liposome nanostructure endowed of excellent stability (>6 months) and skin penetration ability, along with low short-term cytotoxicity, as evaluated via the MTT test. Cytotoxicity tests and lipid droplet analysis give a strong indication that monoolein and lauroylcholine synergistically endanger long-term cells viability.

In vitro release of lysozyme from gelatin microspheres: effect of cross-linking agents and thermoreversible gel as suspending medium.

This study was aimed to characterize the microstructure and the performance of gelatin microspheres (GMs) cross-linked by two different cross-linkers viz. d-glucose and glutaraldehyde. New formulations were obtained, suspending the GMs in a thermoreversible Pluronic F127 (PF127) liquid-crystalline gel.

Aerosol-OT in water forms fully-branched cylindrical direct micelles in the presence of the ionic liquid 1-butyl-3-methylimidazolium bromide.

A recent investigation on the sodium bis(2-ethylhexyl)sulfosuccinate/water/1-butyl-3-methylimidazolium tetrafluoborate (NaAOT/W/bmimBF(4)) system showed that the anionic two-tailed surfactant NaAOT, that is known to form reverse micelles or planar interfaces (typically lamellar liquid crystals), can originate discrete spherical micelles of normal curvature because of strong interactions with the ionic liquid. The goal of the present paper was to detect macro- and microscopic modifications within such a system upon substitution of the ionic liquid's counter-ion tetrafluoroborate with bromide. Firstly, the phase diagram of the NaAOT/water/bmimBr system was determined.

Nucleotide recognition and phosphate linkage hydrolysis at a lipid cubic interface.

Mononucleotides, when entrapped within a mono-olein-based cubic Ia3d liquid crystalline phase, have been found to undergo hydrolysis at the sugar-phosphate ester bond in spite of their natural inertness toward hydrolysis. Here, kinetics of the hydrolysis reaction and interactions between the lipid matrix and the mononucleotide adenosine 5'-monophosphate disodium salt (AMP) and its 2'-deoxy derivative (dAMP) are thoroughly investigated in order to shed some light on the mechanism of the nucleotide recognition and phosphate ester hydrolysis. Experiments evidenced that molecular recognition occurs essentially through the sn-2 and the sn-3 alcoholic OH groups of mono-olein.

Nanoparticles from lipid-based liquid crystals: emulsifier influence on morphology and cytotoxicity.

Here, monoolein-based nanoparticles (NPs), obtained through fragmentation of bulk liquid crystalline phases, and stabilized by two different emulsifiers, namely, Pluronic F127 (PF127) and lauroylcholine chloride (LCh), are investigated for structural features and for short-term in vitro cytotoxicity. Depending on the emulsifiers, different morphologies of the lipid NPs (cubosomes and liposomes) are obtained, as demonstrated by cryo-TEM images. Although NPs offer many advantages in medical applications and various chemicals used for their preparation are under investigation, so far there are no standardized procedures to evaluate cell biocompatibility.

Orientation and specific interactions of nucleotides and nucleolipids inside monoolein-based liquid crystals.

The entrapment of AMP, GMP, CMP, and UMP nucleotides along with two different AMP-based nucleolipids (hydrophobically functionalized nucleotides) inside the liquid crystalline phases of the monoolein/water system is investigated through optical microscopy, small-angle X-ray diffraction (SAXRD), and nuclear magnetic resonance (NMR) techniques. As ascertained mainly through (31)P NMR experiments, when included within the cubic phase, the various nucleotides undergo a slow hydrolysis of the sugar-phosphate ester bond, induced by specific interactions at the monoolein-water interface. Upon aging, the degradation of the nucleotides causes a cubic-to-hexagonal phase transition.

Aerosol-OT forms oil-in-water spherical micelles in the presence of the ionic liquid bmimBF4.

The phase diagram sodium bis(2-ethylhexyl) sulfosuccinate (NaAOT)/water/1-butyl-3-methylimidazolium tetrafluoborate (bmimBF(4)), a polar room temperature ionic liquid, is explored through optical microscopy in polarized light, SAXRD and NMR PGSTE techniques. The analysis of SAXRD and self-diffusion data reveals that the bmim(+) cation is strongly adsorbed at the interface. Data are accounted for by Hill's model for cooperative binding.