Novel Method For Encapsulation Research Articles

Engineering of cardiac microtissues by microfluidic cell encapsulation in thermoshrinking non-crosslinked PNIPAAm gels

Multicellular agglomerates in form of irregularly shaped or spherical clusters can recapitulate cell–cell interactions and are referred to as microtissues. Microtissues gain increasing attention in several fields including cardiovascular research. Cardiac microtissues are evolving as excellent model systems for drug testing in vitro (organ-on-a-chip), are used as tissue bricks in 3D printing processes and pave the way for improved cell replacement therapies in vivo. Microtissues are formed for example in hanging drop culture or specialized microwell plates; truly scalable methods are not yet available. In this study, a novel method of encapsulation of cells in poly-N-isopropylacrylamid (PNIPAAm) spheres is introduced. Murine induced pluripotent stem cell-derived cardiomyocytes and bone marrow-derived mesenchymal stem cells were encapsulated in PNIPAAm by raising the temperature of droplets formed in a microfluidics setup above the lower critical solute temperature (LCST) of 32 °C. PNIPAAM precipitates to a water-insoluble physically linked gel above the LCST and shrinks by the expulsion of water, thereby trapping the cells in a collapsing polymer network and increasing the cell density by one order of magnitude. Within 24 h, stable cardiac microtissues were first formed and later released from their polymer shell by washout of PNIPAAm at temperatures below the LCST. Rhythmically contracting microtissues showed homogenous cell distribution, age-dependent sarcomere organizations and action potential generation. The novel approach is applicable for microtissue formation from various cell types and can be implemented into scalable workflows.

Microencapsulation of Omeprazole by Lactobacillus acidophilus ATCC 4356 Surface Layer Protein and Evaluation of its Stability in Acidic Condition.

The present study introduces a novel method for encapsulation of the acid-labile drug called Omeprazole using Lactobacillus acidophilus (L. acidophilus) ATCC 4356 S-layer protein. Before preparing the Omeprazole suspension, a series of preliminary studies were performed on the Omeprazole powder. For this purpose, some parameters such as melting point, IR spectrum, UV spectrum, and the particle size of Omeprazole powder were investigated. The size reduction process was done in order to achieve an ideal formulation. Ultimately, the resulting powder had an average particle size of 35.516 μm and it was almost uniform. After calculating the amount of S-layer protein required for complete covering of drug particles, the effect of different factors on the drug coating process was investigated with one factor at a time method. Then stability of coated Omeprazole was evaluated in acetate buffer (pH 5). Finally, the maximum coat of drug particles was determined using S- layer protein of Lactobacillus acidophilus ATCC 4356 at 25 °C for 2 h, shaking rate of 100 rpm and ratio of 2:1 for S-layer protein amount/Omeprazole Surface in Tris hydrochloride buffer medium (50 mM, pH 8). The coating of Omeprazole by the S-layer protein decreased the drug decomposition rate up to 2.223.

Encapsulation of zinc phthalocyanine into bovine serum albumin aggregates

Artificial hybridization of molecules with proteins is beneficial for biomedical applications. Herein, we describe a novel method for encapsulation of zinc phthalocyanine (ZnPc) aggregates into bovine serum albumin (BSA) aggregates, but not monomeric BSA. This property is potentially useful for not only photodynamic or photothermal therapy but also development of a novel delivery system for hydrophobic drug molecules.

Rapid and efficient synthesis of isocyanate microcapsules via thiol-ene photopolymerization in Pickering emulsion and its application in self-healing coating

We report an efficient and novel method for encapsulation of isophorone diisocyanate (IPDI) in polythioether microcapsules via thiol-ene click reaction based on Pickering emulsion, which has significantly improved and simplified the preparation process. The resultant microcapsules have spherical shapes with a layer of poly(glycidyl methacrylate) (PGMA) particles covering outside. The diameter ranges from 82.1 to 160.8 μm, which is controlled by the concentration of PGMA particles, and the typical shell thickness is about 9 μm. Moreover, the core content is up to 71% by adjusting the adding ratio of core/shell monomers. Remarkably, the microcapsules have excellently environmental stability that only 18% of the core content drops (from 63.2% to 51.8%) after immersion in water for seven days. These microcapsules could keep their integrity and uniformly disperse in acrylate coatings. In addition, they are proved to be a good self-healing candidate for coatings applied in wet environment.

Effect of Encapsulating Nitrate in Sesame Gum on In vitro Rumen Fermentation Parameters.

Encapsulation is a method used to protect material from certain undesirable environments, for controlled release at a more favorable time and place. Animal productivity would be enhanced if feed additives are delivered to be utilized at their site of action, bypassing the rumen where they are likely to be degraded by microbial action. A novel method of encapsulation with sesame gum was used to coat nitrate, a known enteric methane mitigating agent, and tested for the effect on methane reduction and other in vitro fermentation parameters using rumen fluid from cannulated Hanwoo steers. Orchard grass was used as basal diet for fermentation. The treatments were matrix (1.1 g sesame gum+0.4 g sesame oil cake) only, encapsulated nitrate (matrix+nitrate [21 mM]), free nitrate (21 mM), and a control that contained no additive. Analyses of fermentation parameters were done at 0, 3, 6, 9, 12, 24, and 48 h time periods. In comparison to control, both free and encapsulated nitrate produced significantly reduced (p<0.01) methane (76% less) and also the total volatile fatty acids were reduced. A significantly higher (p<0.01) concentration of ammonia nitrogen was obtained with the encapsulated nitrate treatment (44%) compared to the free form (28%) and matrix only (20%) (p = 0.014). This might suggest slow release of encapsulated nitrate so that it is fully reduced to ammonia. Thus, this pioneering study found a significant reduction in methane production following the use of sesame gum encapsulated nitrate that shows the potential of a controlled release system in enhancing sustainability of ruminant production while reducing/eliminating the risk of nitrite toxicity.

A new method for pH triggered curcumin release by applying poly(l-lysine) mediated nanoparticle-congregation

We introduce a novel method for encapsulation of curcumin by synthesizing microcapsule containing self-assembled nanoparticles using poly (l-lysine), trisodium citrate and silica sol. Such microcapsules can only be prepared in neutral and alkaline environment and unencapsulated curcumin can be effectively removed by simple centrifugation with encapsulation efficiency 57.34%. The particle sizes are in the range 0.7–3μm with an effective diameter 1.05μm. The structure of the microcapsules is dependent upon the solubility of curcumin in the solvent environment, the microcapsule are spherical when prepared in 10% acetone and bowl-shaped/conical when prepared in water suspension, however, the size of these curcumin encapsulated microcapsules remain similar. Fluorescence microscope images confirm that curcumin is predominantly concentrated within the shell wall of the capsules. Photophysical behavior of Micro-curcumin with respect to curcumin alone is evaluated. Release of curcumin is found to be triggered by pH where acidic environment trigger maximum release compared to basic and neutral conditions. Micro-curcumin is as stable as curcumin. Drug release efficiency is found to be 61.44% and the drug release profile of Micro-curcumin follow Higuchi model. It is also revealed that β-diketone group of curcumin responsible for scavenging activity is retained in the Micro-curcumin, thus suggesting applicability of such system as a poorly water soluble drug delivery vehicle. In contrast to other curcumin delivery systems, the presented method is easy, fast and does not need flow rate monitoring device. In addition poly (l-lysine) as a non-toxic and highly stable material that prevents metabolic degradation is used in the present preparation method.

Formation of oil filled nanocapsules with silica shells modified by sequential adsorption of polyelectrolytes

The aim of our work was to develop a novel method of encapsulation of emulsion droplets by silica shells modified by polyelectrolyte multilayers. Dimethyloctadecyl[3-(trimethoxysilyl) propyl]ammonium chloride (DTSACl) was used as the silane for silica shell formation as well as emulsion stabilizer. The silica nanocapsules were subsequently modified by sequential adsorption of polyelectrolytes. Polyelectrolyte multilayers were formed using the saturation method from the various pairs of polyelectrolytes. The average size of nanocapsules with polyelectrolyte shell was 100–120nm. To demonstrate the possibility of encapsulation of hydrophobic substance we enclosed oil-soluble dye Coumarine-6. The obtained capsules’ suspensions were stable for the period of several weeks.

Encapsulated phthalocyanine blue pigment with polymerisable dispersant for inkjet printing inks

Purpose – The purpose of this paper is to provide a novel method for encapsulation of phthalocyanine blue pigment for inkjet printing inks.Design/methodology/approach – Phthalocyanine blue pigment was encapsulated by emulsion polymerisation of styrene and a polymerisable dispersant, allyloxy nonyl‐phenoxy propanol polyoxyethylene ether ammonium sulphonate (ANPS). The encapsulated phthalocyanine blue pigment was further formulated into dispersion. The encapsulated phthalocyanine blue pigment was characterised with transmission electron microscopy (TEM), thermogravimetric analyses (TGA), X‐ray diffraction (XRD), Zeta potential and contact angle measurements. The encapsulated phthalocyanine blue pigment dispersion was evaluated in terms of rheological behaviour, particle size distribution and stability.Findings – TEM and TGA proved that polymer encapsulation layer was formed onto phthalocyanine blue pigment surface. XRD indicated that the crystal structure of phthalocyanine blue pigment was not changed durin...

Studies on Viability of Lactobacillus fermentum by Microencapsulation Using Extrusion Spheronization

A novel method of encapsulation of Lactobacillus fermentum was developed to protect it from different stresses such as thermal, oxidative, pH, and bile salts. L. fermentum was encapsulated in microcrystalline cellulose and sodium alginate by extrusion spheronization and tested for its survival. In the present study, the concentration of microcrystalline cellulose, L. fermentum, and sodium alginate were optimized. Further, response surface methodology was used to determine the appropriate concentrations of components to result in the maximum viability under stress conditions. Spheres of L. fermentum produced by extrusion spheronization were stored at 4°C, and the viability was assessed over 21 d.

A Novel Method for the Encapsulation of Biomolecules into Polymersomes via Direct Hydration

One of the major engineering challenges for the implementation of block copolymer vesicles, or polymersomes, as therapeutic drug carriers is obtaining high encapsulation efficiencies for biomolecules. Here we present a novel method for encapsulation of proteins with high encapsulation efficiency within polymersomes formed from block copolymers of poly(ethylene glycol)-bl-poly(propylene sulfide). By formulation of the neat block copolymer with a low molecular weight poly(ethylene glycol), direct hydration of the formulated mixture yielded polymersomes. We were able to achieve encapsulation efficiencies for ovalbumin at 37%, bovine serum albumin at 19%, and bovine gamma-globulin at 15% when the proteins were included in the hydration solution. The formulation process and the dispersion of polymersomes from the preparation in phosphate-buffered saline were characterized using confocal microscopy, cryogenic transmission electron microscopy, and fluorimetry. We were also successful in the encapsulation of proteinase K, a proteolytic enzyme, and demonstrated by SDS-PAGE that the enzyme was contained inside polymersomes when dispersed in a solution of ovalbumin.

Synthesis and characterization of uniform radiopaque polystyrene microspheres for X‐ray imaging by a single‐step swelling process

Uniform radiopaque polystyrene microspheres of approximately 2.3 +/- 0.2 microm were prepared by a single-step swelling of 2.3 +/- 0.2 microm polystyrene template microspheres, dispersed in an aqueous solution with methylene chloride emulsion droplets containing 2,3,5-triiodobenzoylethyl ester. After completing the swelling process, the methylene chloride was evaporated in order to lock the 2,3,5-triiodobenzoylethyl ester in the polystyrene microspheres. The influence of the weight ratio [2,3,5-triiodobenzoylethyl ester]/[polystyrene] on the % of entrapped 2,3,5-triiodobenzoylethyl ester was elucidated. Characterization of the radiopaque polystyrene microspheres was accomplished by light microscope, FTIR, TGA, SEM, XPS, and elemental analysis. The radiopacity of the microspheres was demonstrated by an imaging technique based on X-ray absorption usually used in hospitals. This novel method of encapsulation of 2,3,5-triiodobenzoylethyl ester within polystyrene microspheres by a single-step swelling process may be used as a model for encapsulation of various hydrophobic radiopaque drugs within uniform polystyrene template particles of various diameters for different X-ray imaging needs, e.g., blood pool, body organs, embolization, dental composition, implants, protheses, and nanocomposites.

Immunoisolated Chromaffin Cells Implanted Into the Subarachnoid Space of Rats Reduce Cold Allodynia in a Model of Neuropathic Pain: A Novel Application of Microencapsulation Technology

Intrathecal transplants of adrenal medullary chromaffin cells relieve chronic pain by secreting catecholamines, opioids, and other neuroactive substances. Recently, macrocapsules with semipermeable membranes were used to isolate immunologically xenogenic chromaffin cells, but the poor viability in vivo of the encapsulated chromaffin cells limited the usefulness of this method. In this study, we used a novel method of encapsulation to increase the viability of chromaffin cells. We found that microencapsulated chromaffin cells that were implanted into the subarachnoid space of rats relieved cold allodynia in a model of neuropathic pain. Furthermore, microencapsulated chromaffin cells were morphologically normal and retained their functionality. These findings suggest that the intrathecal placement of microencapsulated chromaffin cells might be a useful method for treating chronic pain.

A novel method for encapsulation of poorly water-soluble drugs: precipitation in polyelectrolyte multilayer shells.

A novel method to include poorly water-soluble substances into the polyelectrolyte capsules of defined size, stability, composition and affinity properties is proposed. Encapsulation explores the polarity gradient across the capsule wall. Capsules creation makes use of electrostatic interaction and can involve many substances as layer constituents, such as synthetic polyelectrolytes, proteins, nucleic acids, lipids and multivalent dyes. Using capsules made of synthetic polyelectrolytes as a model system was demonstrated how to prepare, to measure and to use this gradient for low molecular weigh materials encapsulation.

A novel method for encapsulation of a liquid crystal in monodisperse micron-sized polymer particles

Liquid crystals (LCs) encapsulated in monodisperse micron-sized polymer particles were prepared to control the size and size distribution of LC droplets in polymer-dispersed LCs. The poly(methyl methacrylate) (PMMA) seed particles were swollen with the mixture of liquid crystal, monomers (methyl methacrylate and styrene) and initiator by using a diffusion-controlled swelling method. A single LC domain was produced by the phase separation between PMMA and LC through polymerization. The optical microscopy and scanning electron microscopy showed that the particles are highly monodisperse with core–shell structure. Moreover, monodisperse LC core domains were confirmed from polarized optical microscope observations. The final particle morphology was influenced by the cross-linking of the seed particle. When linear PMMA particles, which are not cross-linked, were used as a seed, the microcapsules were distorted after annealing for a few days; however, in the case of cross-linked PMMA particles, the core–shell structure was sustained stably after annealing.

A novel method for encapsulation of dyes into AlPO4-8 molecular sieve

Methylene blue and perylene are encapsulated into AlPO4-8 molecular sieve utilising the structural transformation of the large-pore aluminophosphate VPI-5 into AlPO4-8.

A novel method for encapsulation of macromolecules in liposomes

Hemoglobin and alkaline phosphatase were each encapsulated in phosphatidylcholine liposomes using a dehydration-rehydration cycle for liposome formation. In this method, liposomes prepared by sonication are mixed in aqueous solution with the solute desired to be encapsulated and the mixture is dried under nitrogen in a rotating flask. As the sample is dehydrated, the liposomes fuse to form a multilamellar film that effectively sandwiches the solute molecules. Upon rehydration, large liposomes are produced which have encapsulated a significant fraction of the solute. The optimal mass ratio of lipid to solute is approx. 1:2 to 1:3. This method has potential application in large-scale liposome production, since it depends only on a controlled drying and rehydration process, and does not require extensive use of organic solvents, detergents, or dialysis systems.