Efficient preparation of giant vesicles as biomimetic compartment systems with high entrapment yields for biomacromolecules.

The 'lipid-coated ice-droplet hydration method' was applied for the preparation of milliliter volumes of a suspension of giant phospholipid vesicles containing in the inner aqueous vesicle pool in high yield either calcein, α-chymotrypsin, fluorescently labeled bovine serum albumin or dextran (FITC-BSA and FITC-dextran; FITC=fluorescein isothiocyanate). The vesicles had an average diameter of ca. 7-11 µm and contained 20-50% of the desired molecules to be entrapped, the entrapment yield being dependent on the chemical structure of the entrapped molecules and on the details of the vesicle-formation procedure. The 'lipid-coated ice droplet hydration method' is a multistep process, based on i) the initial formation of a monodisperse water-in-oil emulsion by microchannel emulsification, followed by ii) emulsion droplet freezing, and iii) surfactant and oil removal, and replacement with bilayer-forming lipids and an aqueous solution. If one aims at applying the method for the entrapment of enzymes, retention of catalytic activity is important to consider. With α-chymotrypsin as first model enzyme to be used with the method, it was shown that high retention of enzymatic activity is possible, and that the entrapped enzyme molecules were able to catalyze the hydrolysis of a membrane-permeable substrate which was added to the vesicles after their formation. Furthermore, one of the critical steps of the method that leads to significant release of the molecules from the water droplets was investigated and optimized by using calcein as fluorescent probe.

Monodispersed Sirolimus-Loaded PLGA Microspheres with a Controlled Degree of Drug-Polymer Phase Separation for Drug-Coated Implantable Medical Devices and Subcutaneous Injection.

Monodispersed sirolimus (SRL)-loaded poly(lactic-co-glycolic acid) microspheres with a diameter of 1.8, 3.8, and 8.5 µm were produced by high-throughput microfluidic step emulsification─solvent evaporation using single crystal silicon chips consisted of 540-1710 terraced microchannels with a depth of 2, 4, or 5 µm arranged in 10 parallel arrays. Uniform sized droplets were generated over 25 h across all channels. Nearly 15% of the total drug was released by the initial burst release during an accelerated drug release testing performed at 37 °C using a hydrotropic solution containing 5.8 M N,N-diethylnicotinamide. After 24 h, 71% of the drug was still entrapped in the particles. The internal morphology of microspheres was investigated by fluorescence microscopy using Nile red as a selective fluorescent stain with higher binding affinity toward SRL. By increasing the drug loading from 33 to 50 wt %, the particle morphology evolved from homogeneous microspheres, in which the drug and polymer were perfectly mixed, to patchy particles, with amorphous drug patches embedded within a polymer matrix to anisotropic patchy Janus particles. Janus particles with fully segregated drug and polymer regions were achieved by pre-saturating the aqueous phase with the organic solvent, which decreased the rate of solvent evaporation and allowed enough time for complete phase separation. This approach to manufacturing drug-loaded monodisperse microparticles can enable the development of more effective implantable drug-delivery devices and improved methods for subcutaneous drug administration, which can lead to better therapeutic treatments.

Design of nanoemulgel using Argania spinosa microfibrillated cellulose and natural emulsifiers foreseeing melanogenesis enhancement.

Nanotechnology is a route of choice that improves administration and efficacy of bioactive compounds. In this study, nanoemulgels were prepared using microfibrillated cellulose from Argania spinosa shell (AS-MFC) and Argan shell (ASE) or Argan press cake extracts (APC) as natural emulsifiers. Oil-in-water (O/W) nanoemulsions were prepared using different natural emulsifiers or synthetic emulsifiers and presented a nano size (d3,2 < 140 nm). Following that, the nanoemulsions were incorporated within AS-MFC matrix and rheological properties confirmed a shear thinning behavior. Confocal micrographs of nanoemulgels confirmed the dispersion of nanoemulsions in the AS-MFC network without affecting the nanoemulsions stability. Finally, in vitro bioassay on B16F10 using ASE or APC nanoemulsions was conducted. This study confirmed cell permeation in B16F10 cells of formulated nanoemulsions and the upregulation of melanin content up to 30% more that the untreated cells. This study designed novel MFC nanoemulgel with high potential application in healthcare and cosmetic field.

Microfibrillated cellulose from Argania spinosa shells as sustainable solid particles for O/W Pickering emulsions.

Microfibrillated cellulose (MFC) from Argan (Argania spinosa) shells was prepared by chemical purification of cellulose, then mechanical disintegration via high pressure homogenization was performed to isolate fibrils of cellulose. Chemical characterization of raw argan shell (AS-R), purified cellulose (AS-C), and argan shell MFC (AS-MFC) included FT-IR, XRD and NMR. Morphological characterization of AS-MFC was assessed using TEM. Next, the use of AS-MFC as oil-in-water (O/W) emulsions stabilizer was investigated. The particle concentration was observed to affect the long-term stability of the emulsions; high concentrations (0.5-1 % w/w) of AS-MFC resulted in emulsions that were thermodynamically stable during 15 days of storage, which was demonstrated by the droplet's size evolution. The suitable oil concentration for a maximum volume of emulsion using 1 % w/w AS-MFC was demonstrated. The results show that AS-MFC is able to stabilize 70 % w/w MCT oil without visual phase separation. Finally, CLSM shows the adsorption of AS-MFC at the oil-water interface and the formation of a 3D network surrounding oil droplets, confirming Pickering emulsion formation and stabilization.

Gypenosides as natural emulsifiers for oil-in-water nanoemulsions loaded with astaxanthin: Insights of formulation, stability and release properties.

The formulation, physicochemical stability and bioaccessibility of astaxanthin (AST) loaded oil-in-water nanoemulsions fabricated using gypenosides (GPs) as natural emulsifiers was investigated and compared with a synthetic emulsifier (Tween 20) that is commonly applied in food industry. GPs were capable of producing nanoemulsions with a small volume mean diameter (d4,3 = 125 ±â€¯2 nm), which was similar to those prepared using Tween 20 (d4,3 = 145 ±â€¯6 nm) under the same high-pressure homogenization conditions. GPs-stabilized nanoemulsions were stable against droplet growth over a range of pH (6-8) and thermal treatments (60-120 °C). Conversely, instability occurred under acidic (pH 3-5) and high ionic strength (25-100 mM CaCl2) conditions. In comparison with Tween 20, GPs were more effective at inhibiting AST from degradation during 30 days of storage at both 5 and 25 °C. However, GPs led to lower lipid digestion and AST bioaccessibility from nanoemulsions than did Tween 20.

Size control of calcium alginate beads containing living cells using micro-nozzle array.

Size-controlled small (i.e. less than 300 microm) polyelectrolyte complex gel beads are urgently desired for wide-spread application, including use in medical, pharmaceutical, and bioengineering fields. However, it was impossible to obtain smaller beads less than 300 microm with conventional apparatuses. We developed a novel microfluidics device that utilizes silicon micro-nozzle (MN) array, enabling to produce 50-200 microm calcium alginate beads with a narrow size distribution. Alginate aqueous solution was extruded through a precisely fabricated thin (30 microm x 30 microm) and short (500 microm) MN and was sheared by the viscous drag force of oil flow to form alginate droplets. Alginate droplets were immediately reacted with CaCl2 droplets at the downstream of oil flow to form calcium alginate gel beads. This device enabled us to successfully encapsulate living cells into 162 microm calcium alginate beads with maintaining viability, which was confirmed by the expression of marker protein.

Formulation and stabilization of nano-/microdispersion systems using naturally occurring edible polyelectrolytes by electrostatic deposition and complexation.

This review paper presents an overview of the formulation and functionalization of nano-/microdispersion systems composed of edible materials. We first summarized general aspects on the stability of colloidal systems and the roles of natural polyelectrolytes such as proteins and ionic polysaccharides for the formation and stabilization of colloidal systems. Then we introduced our research topics on (1) stabilization of emulsions by the electrostatic deposition using natural polyelectrolytes and (2) formulation of stable nanodispersion systems by complexation of natural polyelectrolytes. In both cases, the preparation procedures were relatively simple, without high energy input or harmful chemical addition. The properties of the nano-/microdispersion systems, such as particle size, surface charge and dispersion stability were significantly affected by the concerned materials and preparation conditions, including the type and concentration of used natural polyelectrolytes. These dispersion systems would be useful for developing novel foods having high functionality and good stability.

Nano-Science-Engineering-Technology Applications to Food and Nutrition.

Nanoscale Science, Engineering and Technology are applied to Food and Nutrition. Various delivery systems include nanoemulsions, microemulsions, solid lipid nanoparticles, micelles, and liposomes. The nanoscale systems have advantages, such as higher bioavailabitity, and other physicochemical properties. The symposium will provide an overview of the formulation, characterization, and utilization of nanotechnology-based food and nutrition.

Membrane process for emulsified waste containing mineral oils and nonionic surfactants (alkylphenolethoxylate).

Using membrane processes we studied the improvement of the treatment of waste emulsified by mineral oils and alkylphenolethoxylate (APE) and investigated diatomaceous earth processing for comparison. A quantitative analysis of the mineral oils and APE using column chromatography was applied to assess these processes. Despite substantial rejection of the turbidity values of emulsified model waste, the percentages of mineral oil and APE rejections using microfiltration (MF) processes were 39-61% and 16-19%, respectively. In contrast, the ultrafiltration (UF) process could reject 97% for the mineral oils and 90% for APE. The diatomaceous earth adsorption processes reduced the mineral oils 40-49% and the APE, 8-14%, and therefore were inferior to the UF process for waste treatment. The average fluxes of both the MF and UF membranes until the volume reduction factor (VRF) reached a value of 5 were almost the same in the range of 8 x 10(-6)-14 x 10(-6) m3 m-2 s-1. For commercial application, decrease in the permeate flux by fouling needs to be resolved.