Whey Protein Isolate Coated Liposomes as Novel Carrier Systems for Astaxanthin

In this work, whey protein isolate (WPI)‐coated astaxanthin‐loaded liposomes are prepared by combining the fabrication of liposomes with the layer self‐assembly deposition technique. The physical properties of such composite carriers are evaluated by zeta potential, particle size, distribution, encapsulation efficiency, and morphology. WPI‐ coated astaxanthin‐loaded liposomes display homodisperse distribution and high encapsulation efficiency with a WPI coating layer surrounding the surface of conventional liposomes by the electrostatic interaction. Fourier transform infrared spectroscopy and X‐ray diffraction analysis reveal that WPI interacts with the lipid bilayer via hydrophobic forces and hydrogen bonding, which result in the successful coating. Based on experimental results of differential scanning calorimetry and thermogravimetric analysis, it is demonstrated that thermal stability of astaxanthin‐loaded liposomes benefits from the formation of surface modification of the WPI‐layer. In addition, the physical stability of WPI‐coated astaxanthin‐loaded liposomes under heating and light is significantly improved as compared with uncoated liposomes. This research might provide scientific guidance for the development of WPI‐coated liposomes as efficient carrier systems for bioactive substances in food and pharmaceutical industry. Practical Applications: To improve lipid membrane stability and to prevent the leakage of encapsulated astaxanthin, a novel carrier system based on WPI coated on the surface of liposomes is prepared through the layer self‐assembly deposition technique. This research suggests that WPI‐coated liposomes represent an effective and stable delivery system for astaxanthin. WPI‐coated liposomes could be developed as efficient carrier systems for bioactive compounds in the food and pharmaceutical industries.     

Functional polyelectrolyte multilayer assemblies for surfaces with controlled wetting behavior

Controlled wetting at surfaces and interfaces is an important area of research with numerous potential commercial applications. Both superhydrophobicity and superhydrophilicity can be used to enable applications such as self‐cleaning, dropwise condensation, or antifogging. Many strategies for creating such surfaces center around biomimicry, replicating the structure of the lotus leaf, for example. Given the potential impact, creating surfaces with these properties using any number of fabrication is of great interest. One very promising fabrication technique, however, for creating these surfaces is the layer‐by‐layer (LbL)‐directed self‐assembly of polyelectrolytes and other charged materials. LbL is a sequential adsorption technique wherein a surface is exposed to first a solution of one charge and then a solution of the opposite charge. LbL has many advantages, including the ability to incorporate many different types of materials and therefore functionality, the ability to conformally coat substrates of complex geometry, and environmentally friendly aqueous processing. This review describes recent progress in using LbL to create surfaces with controlled wetting. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42767.     

DEPOSITION OF AEROSOL PARTICLES ON A SURFACE COMPOSED OF DIFFERENT TYPES OF MATERIALS

Experimental and theoretical studies have been conducted on the deposition of aerosol particles on a surface composed of different types of materials (copper-polyethylene and copper-nickel). Deposition of charged particles is affected by localized electrostatic fields created by the contact potential difference between the different types of materials. The particles charged with positive polarity deposit mainly on the polyethylene or the nickel surfaces, which are negatively charged. The deposition profile has been also controlled by varying the thickness of gold layers deposited on nickel surface.     

Fabrication of amorphous calcium carbonate composite particles‐polymer multilayer films by a layer‐by‐layer method

Organic–inorganic hybrid multilayer films were prepared on a precoated cationic glass substrate by using a layer‐by‐layer (LbL) electrostatic self‐assembly technique with poly(diallyldimethylammonium chloride) as a polycation and submicron‐sized stable amorphous calcium carbonate (ACC) composite particles. The ACC composite particles (ACP) stabilized with poly(acrylic acid) were obtained by a carbonate controlled‐addition method. The average particles size of ACP was (1.8 ± 0.4) × 10² nm. An ethanolic dispersion of ACP was used for the LbL electrostatic self‐assembly technique on the precoated substrate due to instability of ACP in water. The deposition of the particles was confirmed by SEM analysis. The film thickness of the multilayer assembly increased from 230 to 710 nm with increasing the deposition layers. The FTIR spectra of scratched multilayer samples showed characteristic broaden peaks of ACC. The amorphous phase was stable after the LbL assembly process as well as after 2 months in a dry film state. POLYM. COMPOS., 36:330–335, 2015. © 2014 Society of Plastics Engineers     

Kühl‐ und Prozesswasserbehandlung in der Stahlindustrie

Membrane technology offers promising potential for the treatment of (acidic) process water in the steel industry. Innovative tubular membranes were examined, in which tailor‐made polyelectrolytes were applied to a ceramic membrane support by means of layer‐by‐layer deposition. Furthermore, membrane‐supported capacitive deionization was considered for the treatment of cooling water streams, which separates ions at low voltage according to the principle of electrostatic sorption. The positive experiences from two industrial applications are reported.     

Edible oleogels in food products to help maximize health benefits and improve nutritional profiles

Organogelators such as 12‐hydroxystearic acid and ethylcellulose have been shown to structure vegetable oils at levels below 8%. The resultant gels retain the fatty acid profile of the vegetable oil, yet provide solid‐like properties that can successfully replace saturated fats in a variety of food products including cookies, creams, and frankfurters and sausages. Furthermore, organogel technology can be used for the controlled or delayed release of nutraceuticals and pharmaceuticals. With the development of food grade organogelators, this will allow for the use of oleogels in a large variety of food and pharmaceutical applications.     

Exploring forces between individual colloidal particles with the atomic force microscope

Forces between individual colloidal particles can be measured with the atomic force microscope (AFM), and this technique permits the study of interactions between surfaces across aqueous solutions in great detail. The most relevant forces are described by the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory, and they include electrostatic double-layer and van der Waals forces. In symmetric systems, the electrostatic forces are repulsive and depend strongly on the type and concentration of the salts present, while van der Waals forces are always attractive. In asymmetric systems, the electrostatic force can become attractive as well, even when involving neutral surfaces, while in rare situations van der Waals forces can become repulsive too. The enormous sensitivity of the double layer forces on additives present is illustrated with oppositely charged polyelectrolytes, which may induce attractions or repulsions depending on their concentrations.     

Improved hemocompatibility of silk fibroin fabric using layer‐by‐layer polyelectrolyte deposition and heparin immobilization

Silk fibroin has long been used as implantable surgical sutures and it has acceptable mechanical properties and patency rates in animal models and in clinical end‐uses. However, fibroin has been shown to be hemolytic and can cause damage to red blood cells. So to be used as an implantable vascular prosthesis its hemocompatibility needs to be improved. This study has taken two sequential steps to address this problem. First, to create a positively charged layer on the fibroin fibers' surface, a 1.5 and 2.5 bilayers polyelectrolyte surface deposition layer‐by‐layer technique was used with the positive counterion poly(allylamine hydrochloride) and the negative counterion poly(acrylic acid). Second, negatively charged low molecular weight heparin was then immobilized on these positively charged self‐assembled surfaces. The presence of the heparin was confirmed with Alcian Blue staining and a toluidine blue assay, and the increased roughness and hydrophilicity of the modified surfaces were characterized by scanning electron microscopy, contact angle measurements, and atomic force microscopy. In addition, a negligible hemolytic effect, reduced protein adsorption, and a higher concentration of free hemoglobin measured by a kinetic clotting time test were found to be enhanced with the use of 2.5 bilayers compared to the 1.5 bilayers self‐assembly technique. Given the success of these preliminary results, it is anticipated that this novel approach of surface modification and heparin immobilization will demonstrate long‐term patency during future animal trials of small caliber silk fibroin vascular grafts. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40772.     

Triboelectric charging of powders: A review

Particles are often electrostatically charged by frictional contact during powder-handling operations. This phenomenon is called ‘triboelectric charging’ or ‘contact electrification’. The charged particles cause problems such as particle deposition and adhesion. In addition, if particles are excessively charged, an electrostatic discharge may occur, which can pose a risk of fire and explosion hazards; thus, to mitigate the adverse effects, it is important to elucidate the underlying triboelectric charging mechanisms. The electrostatics is, on the other hand, very useful in a number of applications that have been developed using the principles. In this review, the basic concepts and theories of charge transfer between solid surfaces are summarized, and chemical factors depending on materials and environmental effects are described. To theoretically analyze the process of particle charging, relevant models are discussed. Using the models, particle charging by repeated impacts on a wall is formulated. To experimentally evaluate particle charging, measurement and characterization methods are outlined. Furthermore, important applications and computer simulations are described.     

Ultrafine ibuprofen‐loaded polyvinylpyrrolidone fiber mats using electrospinning

BACKGROUND: Drug‐loaded electrospun ultrafine fibers have the advantages of both nanoscale drug delivery systems and conventional solid dosage forms. To improve the control of drug release, the combined use of electrospinning and pharmaceutical polymers has attracted increasing interest recently. RESULTS: Ultrafine drug‐loaded polyvinylpyrrolidone fibers were successfully prepared using an electrospinning process with ibuprofen as the active pharmaceutical ingredient and polyvinylpyrrolidone K30 as the filament‐forming polymer. The analytical results from scanning electron microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy indicated that the drug had good compatibility with the polymer and that the drug was well distributed in the ultrafine fibers as an amorphous physical form. In vitro dissolution tests showed that the fiber mats were able to dissolve within 10 s through a polymer‐controlled mechanism. CONCLUSION: The fast dissolution of drug‐loaded fibers may lead to applications that improve dissolution rates of poorly water‐soluble drugs, or that involve the preparation of oral fast‐dissolving drug delivery systems. Copyright © 2009 Society of Chemical Industry     

CFD simulations of the Andersen cascade impactor: Model development and effects of aerosol charge

Cascade impactors are commonly used to assess the size characteristics of aerosols in toxicology and pharmaceutical applications. These aerosol instruments have been developed and refined over decades. However, a number of questions remain related to impactor performance, including the influence of electrostatic charge on measured size distributions. The objective of this study was to develop a validated CFD model of the Mark II Andersen cascade impactor (ACI) and apply this model to evaluate the effects of particle charge on deposition. The flow field was simulated using a commercial CFD code for incompressible laminar and transitional flows. Particle trajectories and deposition were evaluated using a well tested Lagrangian tracking approach that accounts for impaction, sedimentation, diffusion, and electrostatic attraction. Particle charge levels typical of dry powder inhaler (DPI) and metered dose inhaler (MDI) aerosols were considered for a particle size range of 0.3–12 μm. As a model validation, computational predictions of cutoff d₅₀ diameters for each of the eight ACI stages were found to be within 10% difference of existing experimental and manufacturer data. Results indicated that charges consistent with DPI and MDI aerosols increased deposition fraction in Stages 0–3 by up to 30% and increased deposition fraction in Stages 4–7 by up to an order of magnitude. For Stages 0–3, both DPI and MDI charges reduced the d₅₀ value by approximately 10% or less. In contrast, charged aerosols reduced the d₅₀ values in Stages 4 and 5 by 200% and 60%, respectively. All charged submicrometer aerosols considered deposited in Stages 6 and 7. Increasing the particle charge by an order of magnitude from DPI to MDI values had a relatively small effect on further decreasing the cutoff size of each stage. In conclusion, these results can be used to approximate the actual aerodynamic diameter of a charged pharmaceutical aerosol based on measurements in a standard ACI. Future applications of the developed ACI model include evaluating the influence of space charge on deposition and quantifying the effects of aerosol condensation and evaporation on size assessment.     

Prospects for the application of dielectric heating processes in the pre‐treatment of oilseeds

In some branches of industry dielectric heating processes are used in a wide range of different applications like drying of agricultural products and textiles or disinfection processes in the food processing and pharmaceutical industry. This report shows potential uses of this technology for thermal pre‐treatment of oilseeds. Therefore, the basic principles of the dielectric heating mechanism and some resulting characteristics are presented in comparison to conventional heating systems. Special aspects of the application of microwaves and high‐frequency energy for thermal pre‐treatment of oilseeds are also presented. Finally, some scenarios for imaginable applications of this technology in the European oil milling industry are discussed.     

Electrostatic effects on inertial particle transport in bifurcated tubes

Most aerosols found naturally in the ambient environment or those dispersed from artificial devices such as dry powder inhalers, are electrically charged. It is known that a strong electrostatic charge on aerosols can result in transport behavior dramatically different from that of uncharged aerosols, even in the absence of an external electric field. In the present work, we study pneumatic transport of corona‐charged particles in bifurcated tubes. This is accomplished by tracking the motion of discrete particles numerically under the influence of drag, gravitational, and electrostatic forces. The model aerosol is fly ash powder, whose size and charge distributions have been determined experimentally. The electrical mobility of the charged particle cloud is modeled through coulombic interactions between discrete point charges. For the case of polydispersed particles electrically charged across a distribution, the deposition efficiency was found to be greater than what is indicated by the mean charge and size. In particular, use of negatively charged fly ash powder of mean size of 2 μm and mean charge of ?1.5 C/kg led to significant increase in deposition efficiency (～29%) compared with uncharged fly ash powder of the same size distribution (～8%). Analysis of particle residence times suggests significant interaction between electrical and drag forces. These findings could have implications for pneumatic powder conveying or pulmonary drug delivery applications. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Twenty-first century research needs in electrostatic processes applied to industry and medicine

From the early 20th century Nobel Prize winning (1923) experiments with charged oil droplets, resulting in the discovery of the elementary electronic charge by Robert Millikan, to the early 21st century Nobel Prize (2002) awarded to John Fenn for his invention of electrospray ionization mass spectroscopy and its applications to proteomics, electrostatic processes have been successfully applied to many areas of industry and medicine. Generation, transport, deposition, separation, analysis, and control of charged particles involved in the four states of matter: solid, liquid, gas, and plasma are of interest in many industrial and biomedical processes. In this paper, we briefly discuss some of the applications and research needs involving charged particles in industrial and medical applications including: (1) generation and deposition of unipolarly charged dry powder without the presence of ions or excessive ozone, (2) control of tribocharging process for consistent and reliable charging, (3) thin film powder coating and powder coating on insulative surfaces, (4) fluidization and dispersion of fine powders, (5) mitigation of Mars dust, (6) effect of particle charge on the lung deposition of inhaled medical aerosols, (7) nanoparticle deposition, and (8) plasma/corona discharge processes. A brief discussion on the measurements of charged particles and suggestions for research needs are also included.     

DEM‐CFD modeling of particle systems with long‐range electrostatic interactions

To investigate dynamic behaviors of monocharged particle systems, a direct truncation (DT) method and a hybrid particle‐cell (HPC) method are implemented into the discrete element method coupled with computational fluid dynamics (DEM‐CFD) with defined cutoff distances. The DT method only considers electrostatic interactions between particles within the cutoff distance while the HPC method computes electrostatic interactions in the entire computational domain. The deposition process of monocharged particles in a container in air was simulated using the developed DEM‐CFD. It was found that using the DT method, the macrostructure, evolution of granular temperature, and radial distribution function of the particle system were sensitive to the specified cutoff distance. In contrast, using the HPC method, these results were independent of the specified cutoff distance, as expected. This implies that, although electrostatic interactions between particles with large separation distances are weak, they should be considered in DEM‐CFD for accurate modeling of charged particle systems. © 2015 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 61: 1792–1803, 2015     

Bioreaktionstechnik in mikrofluidischen Reaktoren

In the last decade micro bioreactor (MBR) technology has made rapid advances in biotechnology process development and in the investigation of various biological systems from industrial to pharmaceutical biotechnology applications. MBRs range in complexity from simple micro titer‐based systems to complex automated parallel bioreactors designed to allow the meaningful scale‐up/ ‐down of conventional pilot and large‐scale bioprocesses. MBR technology and the capability to monitor cultivation process variables in situ, provide real‐time and quantitative data from the microliter cultivation. This paper gives an overview of micro technologically fabricated MBRs, for the high‐throughput operation, its design, advantages and current limitations and potential future challenges in different biotechnological fields.     

A CONSISTENT ALTERNATIVE TO THE DLVO THEORY

An overview of a new theory of repulsions between charged surfaces is given. The theory is based on consistent Maxwellian electrostatics with linear distribution laws, which predict the existence of co-ion exclusion boundaries. The theory covers interactions from infinity to contact in terms of three electrostatic models: the low potential (LP) model, the co-ion exclusion (CX) model, and the high potential (HP) model. The new theory predicts short-range electrostatic forces that are much stronger than those derived from the nonlinear DLVO theory; no universal Van der Waals adhesion at short distances is predicted. For planar charged surfaces, these short-range electrostatic forces decay according to the inverse square of separation in accordance with experimental observations.     

A consistent alternative to the dlvo theory

An overview of a new theory of repulsions between charged surfaces is given. The theory is based on consistent Maxwellian electrostatics with linear distribution laws, which predict the existence of co-ion exclusion boundaries. The theory covers interactions from infinity to contact in terms of three electrostatic models: the low potential (LP) model, the co-ion exclusion (CX) model, and the high potential (HP) model. The new theory predicts short-range electrostatic forces that are much stronger than those derived from the nonlinear DLVO theory; no universal Van der Waals adhesion at short distances is predicted. For planar charged surfaces, these short-range electrostatic forces decay according to the inverse square of separation in accordance with experimental observations.     

Strategies for Controlled Placement of Nanoscale Building Blocks

The capability of placing individual nanoscale building blocks on exact substrate locations in a controlled manner is one of the key requirements to realize future electronic, optical, and magnetic devices and sensors that are composed of such blocks. This article reviews some important advances in the strategies for controlled placement of nanoscale building blocks. In particular, we will overview template assisted placement that utilizes physical, molecular, or electrostatic templates, DNA-programmed assembly, placement using dielectrophoresis, approaches for non-close-packed assembly of spherical particles, and recent development of focused placement schemes including electrostatic funneling, focused placement via molecular gradient patterns, electrodynamic focusing of charged aerosols, and others.     

Liquid membrane technology: fundamentals and review of its applications

OVERVIEW: During the past two decades, liquid membrane technology has grown into an accepted unit operation for a wide variety of separations. The increase in the use of this technology owing to strict environmental regulations and legislation together with the wider acceptance of this technology in preference to conventional separation processes has led to a spectacular advance in membrane development, module configurations, applications, etc. IMPACT: Liquid membrane technology makes it possible to attain high selectivity as well as efficient use of energy and material relative to many other separation systems. However, in spite of the known advantages of liquid membranes, there are very few examples of industrial applications because of the problems associated with the stability of the liquid membrane. APPLICATIONS: Liquid membrane technology has found applications in the fields of chemical and pharmaceutical technology, biotechnology, food processing and environmental engineering. On the other hand, its use in other fields, such as in the case of hydrogen separation, the recovery of aroma compounds from fruits, the application of ionic liquids in the membrane formulation, etc., is increasing rapidly. Copyright © 2009 Society of Chemical Industry