Modulation of the crystallization of rapeseed oil using lipases and the impact on ice cream properties.

We investigated the possibility to use rapeseed as a main oil in ice cream formulations by changing its functionality when using different kinds of lipases. Through a 24 h-emulsification and a centrifugation, the modified oils were further used as functional ingredients. All lipolysis was first assessed as a function of time by 13C NMR, where triglycerides consumption and the formation of low-molecular polar lipids (LMPL: monoacylglycerol and free fatty acids, FFAs) were selectively identified and compared. The more the FFAs, the sooner the crystallization (from -55 to -10 °C) and the later the melting temperatures (from -17 to 6 °C) measured by differential scanning calorimetry. These modifications were exploited in ice cream formulations with a significant impact on overall hardness (range of 60-216 N) and flowing during defrosting (from 1.29 to 0.35g/min). The global behavior of products can be controlled by the composition of LMPL within oil.

Study of rapeseed oil gelation induced by commercial monoglycerides using a chemometric approach.

Commercial oleogelators rich in monoglycerides (MGs) are complex mixtures of acylglycerides with variable gelling properties, depending on the oil used and their concentration. In this study we developed a chemometric approach to identify the key parameters involved in gelling process. Analytical parameters have been defined, using GC and NMR analysis to identify fatty acids and acylglycerides composing the mixtures. Specific acylglyceride families and compound ratios were calculated to streamline the analytical results. To determine the key analytical parameters, artificial neural networks were used in a QSPR study related to the gelling properties measured by rheology through oscillatory experiments. At low oleogelator concentrations, the MGs especially rich in C16:0 and the ratio of specific isomers both have a positive influence on G'. For high oleogelator concentrations, C18:0-rich acylglycerides and unsaturated/saturated fatty acid ratios have a positive influence on G'. Conversely, at low concentrations, C18:0-rich acylglycerides show a lesser effect on G'.

Organogel Nanoparticles as a New Way to Improve Oral Bioavailability of Poorly Soluble Compounds.

PURPOSE: The aim of the study was to evaluate organogel nanoparticles as a lipophilic vehicle to increase the oral bioavailability of poorly soluble compounds. Efavirenz (EFV), a Biopharmaceutical Classification System (BCS) Class II, was used as drug model. METHODS: Organogel nanoparticles loaded with EFV were formulated with sunflower oil, 12-hydroxystearic acid (HSA) and polyvinyl alcohol (PVA). Various parameters have been investigated in the current study such as (i) the release profile of organogel assessed by USP 4 cell flow dialysis, (ii) the impact of organogel on intestinal absorption, using Caco-2 cells as in vitro model and jejunum segments as ex vivo assay and (iii) the bioavailability of organogel following oral pharmacokinetic study. RESULTS: 250-300 nm spherical particles with a final concentration of 4.75 mg/mL drug loading were obtained, corresponding to a thousand fold increase in EFV solubility, combined to a very high encapsulation efficiency (>99.8%). Due to rapid diffusion, drug was immediately released from the nanoparticles. The biopharmaceutical evaluation on ex vivo jejunum segments demonstrated an increased absorption of EFV from organogel nanoparticles compare to a native EFV suspension. In vitro assays combining Caco-2 cell cultures with TEM and confocal microscopy demonstrated passive diffusion, while paracellular integrity and endocytosis activity remain expelled. Oral pharmacokinetics of EFV organogel nanoparticles improve oral bioavailability (Fr: 249%) and quick absorption compared to EFV suspension. CONCLUSION: Organogel nanoparticles increase the bioavailability of BCS Class II drugs. The main phenomena is simply oil transfer from the gelled particles through the cell membrane.

How an organogelator can gelate water: gelation transfer from oil to water induced by a nanoemulsion.

A hydrogel can be formed by an organogelator in the presence of a nanoemulsion. It is expected that this is due to a gelation transfer from oil to water. The system started with an oil-in-water nanoemulsion prepared according to a phase inversion temperature (PIT) process. Into this nanoemulsion consisting of Kolliphor® RH40 and Brij® L4 as surfactants, and Miglyol® 812 as oil and water, we introduced the organogelator 12-hydroxyoctadecanoic acid (12-HOA) in the oil phase. After cooling at room temperature, a slow reversible gelation of the water phase occurred with persistence of the nanoemulsion. This thermally reversible system was investigated using various techniques (rheology, turbidimetry, optical and electron microscopies, scattering techniques). Successive stages appeared during the cooling process after the nanoemulsion formation, corresponding to the migration and self-assembly of the organogelator from the oil nanodroplets to the water phase. According to our measurements and the known self-assembly of 12-HOA, a mechanism explaining the formation of the gelled nanoemulsion is proposed.

Trace metals in polyethylene debris from the North Atlantic subtropical gyre.

Plastic pollution in the marine environment poses threats to wildlife and habitats through varied mechanisms, among which are the transport and transfer to the food web of hazardous substances. Still, very little is known about the metal content of plastic debris and about sorption/desorption processes, especially with respect to weathering. In this study, plastic debris collected from the North Atlantic subtropical gyre was analyzed for trace metals; as a comparison, new packaging materials were also analyzed. Both the new items and plastic debris showed very scattered concentrations. The new items contained significant amounts of trace metals introduced as additives, but globally, metal concentrations were higher in the plastic debris. The results provide evidence that enhanced metal concentrations increase with the plastic state of oxidation for some elements, such as As, Ti, Ni, and Cd. Transmission electron microscopy showed the presence of mineral particles on the surface of the plastic debris. This work demonstrates that marine plastic debris carries complex mixtures of heavy metals. Such materials not only behave as a source of metals resulting from intrinsic plastic additives but also are able to concentrate metals from ocean water as mineral nanoparticles or adsorbed species.

Small Microplastics As a Main Contributor to Plastic Mass Balance in the North Atlantic Subtropical Gyre.

Estimates of cumulative plastic inputs into the oceans are expressed in hundred million tons, whereas the total mass of microplastics afloat at sea is 3 orders of magnitude below this. This large gap is evidence of our ignorance about the fate of plastics, as well as transformations and sinks in the oceans. One of the current challenges consists of identifying and quantifying plastic particles at the microscale, the small microplastics (SMP, 25-1000 µm). The aim of the present study is to investigate SMP concentration in count and in mass at the sea surface in the North Atlantic subtropical gyre during the sea campaign Expedition 7 th Continent. After isolation, SMP were characterized by micro-Fourier-transform infrared spectroscopy. Microplastic distribution was modeled by a wind-driven vertical mixing correction model taking into account individual particle properties (dimension, shape and density). We demonstrate that SMP buoyancy is significantly decreased compared to the large microplastics (LMP, 1-5 mm) and consequently more susceptible to vertical transport. The uncorrected LMP concentration in count was between 13 000 and 174 000 pieces km-2, and was between 5 and 170 times more abundant for SMP. With a wind-driven vertical mixing correction, we estimated that SMP were 300 to 70 000 times more abundant than LMP. When discussing this in terms of weight after correction, LMP concentrations were between 50 and 1000 g km-2, and SMP concentrations were between 5 and 14 000 g km-2.

Interfacial activity and emulsifying behaviour of inclusion complexes between helical polysaccharides and flavouring molecules resulting from non-covalent interactions.

This study deals with the fabrication of inclusion complexes starting from a cross coupling of seven helical polysaccharides (host) and six flavouring agents (guest). Neither of the substrates is considered as an emulsifier when studied alone. Due to a complexation mechanism, the presence of intermolecular hydrogen bonds between substrates was highlighted by infra-red spectroscopy and 13C NMR. In addition, depending on the polysaccharide used, the guest molecule could be preferentially located either inside or in the interstitial spaces of the helix. In a comparison between raw substrates, the inclusion complexes obtained presented the unique interfacial activity of decreasing surface tension values (γ) and, in some cases, their behaviour in water was similar to that of regular emulsifiers due to the presence of a critical aggregation concentration (CAC). Substrate concentrations and the ratios between them were the main parameters investigated in this study, which focused on the two inclusion complexes: vanillin/amylose and vanillin/ι-carrageenan. The first decreased γ values by as much as 53mN/m with a double transition, whereas the second could cause γ fall to 36mN/m with a regular break. In addition, these systems were able to stabilize foams for up to 60min, which confirmed their unique emulsifying properties.

Anticyclonic eddies increase accumulation of microplastic in the North Atlantic subtropical gyre.

There are fundamental gaps in our understanding of the fates of microplastics in the ocean, which must be overcome if the severity of this pollution is to be fully assessed. The predominant pattern is high accumulation of microplastic in subtropical gyres. Using in situ measurements from the 7th Continent expedition in the North Atlantic subtropical gyre, data from satellite observations and models, we show how microplastic concentrations were up to 9.4 times higher in an anticyclonic eddy explored, compared to the cyclonic eddy. Although our sample size is small, this is the first suggestive evidence that mesoscale eddies might trap, concentrate and potentially transport microplastics. As eddies are known to congregate nutrients and organisms, this phenomenon should be considered with regards to the potential impact of plastic pollution on the ecosystem in the open ocean.

To what extent are microplastics from the open ocean weathered?

It is necessary to better characterize plastic marine debris in order to understand its fate in the environment and interaction with organisms, the most common type of debris being made of polyethylene (PE) and polypropylene (PP). In this work, plastic debris was collected in the North Atlantic sub-tropical gyre during the Expedition 7th Continent sea campaign and consisted mainly in PE. While the mechanisms of PE photodegradation and biodegradation in controlled laboratory conditions are well known, plastic weathering in the environment is not well understood. This is a difficult task to examine because debris comes from a variety of manufactured objects, the original compositions and properties of which vary considerably. A statistical approach was therefore used to compare four sample sets: reference PE, manufactured objects, mesoplastics (5-20 mm) and microplastics (0.3-5 mm). Infrared spectroscopy showed that the surface of all debris presented a higher oxidation state than the reference samples. Differential scanning calorimetry analysis revealed that the microplastics were more crystalline contrarily to the mesoplastics which were similar to references samples. Size exclusion chromatography showed that the molar mass decreased from the references to meso- and microplastics, revealing a clear degradation of the polymer chains. It was thus concluded that the morphology of marine microplastic was much altered and that an unambiguous shortening of the polymer chains took place even for this supposedly robust and inert polymer.

Evaluation of Organogel Nanoparticles as Drug Delivery System for Lipophilic Compounds.

The purpose of the study was to evaluate organogel nanoparticles as a drug delivery system by investigating their stability, according to the formulation strategy, and their release profile. The gelled nanoparticles were prepared by hot emulsification (above the gelation temperature) of an organogel in water, and cooling at room temperature. In the first step, we used DLS and DSC to select the most suitable formulations by optimizing the proportion of ingredients (HSA, PVA, castor oil) to obtain particles of the smallest size and greatest stability. Then, two lipophilic drug models, indomethacin and ketoconazole were entrapped in the nanoparticles made of castor oil gelled by 12-hydroxystearic acid. Thermal studies (DSC) confirmed that there was no significant alteration of gelling due to the entrapped drugs, even at 3% w/w. Very stable dispersions were obtained (>3 months), with gelled oil nanoparticles presenting a mean diameter between 250 and 300 nm. High encapsulation efficiency (>98%) was measured for indomethacin and ketoconazole. The release profile determined by in vitro dialysis showed an immediate release of the drug from the organogel nanoparticles, due to rapid diffusion. The study demonstrates the interest of these gelled oil nanoparticles for the encapsulation and the delivery of lipophilic active compounds.

Understanding the Fragmentation Pattern of Marine Plastic Debris.

The global estimation of microplastic afloat in the ocean is only approximately 1% of annual global plastic inputs. This reflects fundamental knowledge gaps in the transformation, fragmentation, and fates of microplastics in the ocean. In order to better understand microplastic fragmentation we proceeded to a thorough physicochemical characterization of samples collected from the North Artlantic subtropical gyre during the sea campaign Expedition seventh Continent in May 2014. The results were confronted with a mathematical approach. The introduction of mass distribution in opposition to the size distribution commonly proposed in this area clarify the fragmentation pattern. The mathematical analysis of the mass distribution points out a lack of debris with mass lighter than 1 mg. Characterization by means of microscopy, microtomography, and infrared microscopy gives a better understanding of the behavior of microplastic at sea. Flat pieces of debris (2 to 5 mm in length) typically have one face that is more photodegraded (due to exposure to the sun) and the other with more biofilm, suggesting that they float in a preferred orientation. Smaller debris, with a cubic shape (below 2 mm), seems to roll at sea. All faces are evenly photodegraded and they are less colonized. The breakpoint in the mathematical model and the experimental observation around 2 mm leads to the conclusion that there is a discontinuity in the rate of fragmentation: we hypothesized that the smaller microplastics, the cubic ones mostly, are fragmented much faster than the parallelepipeds.

Factors influencing the erosion rate and the drug release kinetics from organogels designed as matrices for oral controlled release of a hydrophobic drug.

This article proposes solid-like systems from sunflower oil structured with a fibrillar network built by the assembly of 12-hydroxystearic acid (12-HSA), a gelator molecule for an oil phase. The resulting organogels were studied as oral controlled release formulations for a lipophilic drug, Efavirenz (EFV), dissolved in the oil. The effects of the gelator concentration on the thermal properties of the organogels were studied by Differential Scanning Calorimetry (DSC) and showed that drug incorporation did not change the sol-gel-sol transitions. The erosion and drug release kinetics from organogels under conventional (filling gelatin capsules) or multiparticulate (beads obtained by prilling) dosage forms were measured in simulated gastric and intestinal fluids. EFV release profiles were analyzed using model-dependent (curve-fitting) and independent approaches (Dissolution Efficiency DE). Korsmeyer-Peppas was the best fitting release kinetic model based on the goodness of fit, revealing a release mechanism from organogels loaded with EFV different from the simple drug diffusion release mechanism obtained from oily formulations. From organogels, EFV probably diffuses through an outer gel layer that erodes releasing oil droplets containing dissolved EFV into the aqueous medium.

Development of an extraction method based on new porous organogel materials coupled with liquid chromatography-mass spectrometry for the rapid quantification of bisphenol A in urine.

A new method based on the use of porous organogel materials in combination with liquid chromatography-tandem mass spectrometry (LC-MS-MS) was assessed for the quantification of trace contaminants in complex matrices. As a demonstration of the use of these new materials, the contaminant chosen as a model was bisphenol A (BPA) and its extraction was investigated in urine. Organogel materials consist of an organic solvent immobilized by an organogelator. The composition of the organogel materials was optimized in terms of extraction efficiency and compatibility with LC-MS-MS. Porosity was introduced into the organogel by means of the particulate leaching method using sugar crystals. This new absorbing material is simple to use; the extraction method is reduced to a few steps. The originality of the method lies in the complete dissolution of the material for analysis by LC-MS-MS. The matrix effect of the organogel components was studied and was found to be minimal in atmospheric-pressure chemical ionization (APCI) compared to electrospray ionization (ESI) in negative mode. The influence of matrix components on the extraction was investigated by working with different media (acidified water, synthetic urine, horse urine and human urine). The partition coefficient was not affected within the margin of error (±0.1). After optimization, bisphenol A recoveries from urine samples reached 80%. The actual concentration factor was 10. The relative standard deviation (RSD, n=6) for the extraction and determination of BPA in horse urine spiked at 10ngmL(-1) was 9%. Tests with spiked human urine showed that the extraction performances were the same as with the solutions tested previously. The use of porous organogel allowed a fast, simple, sensitive, robust, green method to be developed for the determination of trace contaminants in complex matrices.

Gelled oil particles: a new approach to encapsulate a hydrophobic metallophthalocyanine.

Chloroaluminum phthalocyanine (ClAlPc) is a promising sensitizer molecule for photodynamic therapy, but its hydrophobicity makes it difficult to formulate. In this study, we have efficiently encapsulated ClAlPc into gelled soybean oil particles dispersed in water. 12-Hydroxystearic acid (HSA) and polyethyleneimine (PEI) were the gelling and stabilizing agents, respectively. The preparation process involved hot emulsification above the gelation temperature (Tgel), followed by cooling to room temperature, which gave a colloidal dispersion of gelled particles of oil in aqueous medium. The gelled particles containing ClAlPc had a medium diameter of 280 nm, homogeneous size distribution (polydispersity index ≈0.3) and large positive zeta potential (about +50 mV) and showed a spherical morphology. The gelled oil particle formulations exhibited good physical stability over a 6-month period. ClAlPc interfered with the HSA self-assembly only slightly, and decreased the gelation temperature to a small extent; however it did not affect gelation process of the oil droplets. The amounts of PEI and HSA employed during the preparation allowed us to control particle size and the dispersion stability, a phenomenon that results from complex electrostatic interactions between the positively charged PEI and the negatively charged HSA fibers present on the gelled particles surface. In summary, by using the right ClAlPc, HSA, and PEI proportions, we prepared very stable dispersions of gelled soybean oil particles with excellent ClAlPc encapsulation efficiency. The obtained colloidal formulation of gelled oil particles loaded with ClAlPc shall be very useful for photodynamic therapy protocols.

Functionalized vesicles based on amphiphilic boronic acids: a system for recognizing biologically important polyols.

We report on a new approach for creating water-soluble functionalized vesicles employing N-alkyl-3-boronopyridinium triflates (alkyl = Me, C12H25, C16H33) as sensors for monosaccharides. The nanoaggregate properties were studied by means of DLS, TEM, high-resolution (1)H NMR, and the solvatochromic dyes Reichardt's betaine and Methyl Orange. The vesicles were shown to have 30-200 nm diameters depending on the amphiphile chain length. Diol binding to the vesicles was studied by steady-state fluorescence and UV-vis using Alizarin Red S as a probe in the solution at pH 7.4 in the presence and in the absence of D-glucose and D-fructose. Strong sensing ability of boronic acid functional moieties in the order D-fructose > D-glucose was demonstrated, and apparent binding constants were estimated.

DNA photo-oxidative damage hazard in transfection complexes.

Complexes of DNA with various cationic vectors have been largely used for nonviral transfection, and yet the photochemical stability of DNA in such complexes has never been considered. We studied, for the first time, the influence of DNA complexation by a cationic lipid and polymers on the amount of damage induced by benzophenone photosensitization. The localization of benzophenone inside the hydrophobic domains formed by a cationic lipid, DOTAP (N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride), and close to DNA, locally increases the photoinduced cleavage by the reactive oxygen species generated. The same effect was found in the case of DNA complexation with an amphiphilic polymer (polynorbornenemethyleneammonium chloride). However, a decrease in DNA damage was observed in the case of complexation with a hydrophilic polymer (polyethylenimine). The DNA protection in this case was because of the absence of benzophenone hydrophobic incorporation into the complex, and to DNA compaction which decreased the probability of radical attack. These results underline the importance of the chemical structure of the nonviral transfection vector in limiting the risks of photo-oxidative damage of the complexed DNA.

Evaluation of biocompatible stabilised gelled soya bean oil nanoparticles as new hydrophobic reservoirs.

Based on the organogel concept, in which an oil is trapped in a network of low-molecular-mass organic gelator fibres creating a gel, a formulation of gelled soya bean oil nanoparticles was evaluated for its capacity to form biocompatible hydrophobic reservoirs. The aqueous dispersions of nanoparticles were prepared by hot emulsification (T° > Tgel) and cooling at room temperature in the presence of polyethyleneimine (PEI). The dispersions were stabilised by the electrostatic interactions between the positively charged amino groups of the PEI and the negatively charged carboxylates of the gelator fibres present at the surface of the particles. The aqueous dispersions were highly stable (several months) and the gelled particles were able to entrap a hydrophobic fluorescent model molecule (Nile red), allowing testing in cells. The gelled oil nanoparticles were found to be biocompatible with the tested cells (keratinocytes) and had the ability to become rapidly internalised. Thus, organogel-based nanoparticles are a promising hydrophobic drug delivery system.

Preparation and evaluation of microporous organogel scaffolds for cell viability and proliferation.

Various porous scaffolds utilizing an organogel were prepared by particulate-leaching method. The porous organogels were made of biodegradable, non-toxic ingredients like soybean oil or caprylic/capric triglyceride as the organic liquids and 12-hydroxystearic acid as the gelator. The scaffolds possessed an effective porosity of 56-65%, and good pore interconnectivity with an average pore size from 220 to 290mum. The biodegradability of such materials was evaluated and lipases were able to totally degrade the scaffolds. The porosity of the material associated with high draining led to suitable scaffolds which were evaluated for CHO cell viability and proliferation using the MTT test. This evaluation was performed over a period of 3 weeks and showed a greater ability to promote cell proliferation for the soybean oil based scaffold than for the caprylic/capric triglyceride one. The histological investigations revealed that this scaffold was able to promote cell colonization and attachment and could induce the production of collagen.

Rheological characterization of a new type of colloidal dispersion based on nanoparticles of gelled oil.

The rheological properties of a new type of colloidal dispersion based on nanoparticles of gelled oil have been characterized. The nanoparticles (mean diameter approximately 250 nm) were viscoelastic droplets of dicaprylyl ether gelled by 12-hydroxystearic acid (HSA) and were stabilized in aqueous solutions by cetyltrimethylammonium bromide. The effects of the volume fraction of the dispersed organogel phase and of the organogelator concentration upon viscoelasticity of the dispersion were investigated and compared to the corresponding emulsion (without HSA). The shear viscosity of the dispersions of organogel droplets and the elastic and viscous moduli (G' and G'') were found to increase when the proportion of organogelator was increased. More surprisingly, the shear-thinning behavior was also more pronounced. The rheological behavior of the dispersions could be explained by strong interactions between some gelled particles. This hypothesis was supported by electron microscopy observations showing some particles bridged together by ribbons of HSA fibers.