Microcapsules Research Articles

Garlic Oil Nanoemulsions Hybridized in Calcium Alginate Microcapsules for Functional Bread

The aim of this study was to investigate the effect of incorporation of hybrid GO MCs (garlic oil microcapsules) on the physico-sensory parameters of bread. Hybridized calcium alginate microcapsules containing nanoemulsions of garlic oil (GO) were prepared by using air atomization technique. Functional bread fortified with 5% hybrid GO MCs showed fourfold decrease in thiobarbituric acid-reactive substance values (0.132–0.221 μmol MDA/g oil) than the market garlic (unencapsulated) bread (0.185–0.816 μmol MDA/g oil) throughout the storage period. Hardness increased significantly (P < 0.001), whereas no change in the cohesiveness and springiness was observed in all bread samples throughout the storage period (7 days). Functional bread fortified with GO MCs showed lower hardness values (317.14 ± 0.21–564.88 ± 0.11) as compared to the control bread (383.69 ± 0.40–827.97 ± 0.08) and market garlic bread (322.64 ± 0.24–675.27 ± 0.15). There was no significant difference (P < 0.05) in all the sensory parameters observed in the control bread and functional bread fortified with GO-hybrid MCs. Hence, functional bread fortified with GO-hybrid MCs achieved improved physical/sensory parameters when compared to market garlic bread.

Easily Tunable Membrane Thickness of Microcapsules by Using a Coordination Assembly on the Liquid-Liquid Interface.

A model solvent, 1,3,5-trimethylbenzene, was encapsulated using coordination assembly between metal ions and tannic acid to reveal the deposition of coordination complexes on the liquid-liquid interface. The deposition was confirmed by zeta potential, energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Scanning electron microscopy and transmission electron microscopy were integrated to characterize the microcapsules (MCs). According to atomic force microscopy height analysis, membrane thickness of the MCs increased linearly with sequential deposition. For MCs prepared using the Fe3+-TA system, the average membrane thicknesses of MCs prepared with 2, 4, 6, and 8 deposition cycles were determined as 31.3 ± 4.6, 92.4 ± 15.0, 175.4 ± 22.1, and 254.8 ± 24.0 nm, respectively. Dissolution test showed that the release profiles of all the four tested MCs followed Higuchi kinetics. Membrane thicknesses of MCs prepared using the Ca2+-TA system were much smaller. We can easily tune the membrane thickness of the MCs by adjusting metal ions or deposition cycles according to the application requirements. The convenient tunability of the membrane thickness can enable an extensive use of this coordination assembly strategy in a broad range of applications.

Isophorone Diisocyanate (IPDI) Microencapsulation for Mono-Component Adhesives: Effect of the Active H and NCO Sources.

Polyurea/polyurethane (PUa/PU) shell microcapsules (MCs), containing high loadings of isophorone diisocyanate (IPDI) in the core, were developed to enable the production of mono-component, eco-friendly and safer adhesive formulations for the footwear industry. IPDI microencapsulation was obtained via oil–in–water (O/W) microemulsion combined with interfacial polymerization. A methylene diphenyl diisocyanate (MDI) compound (a commercial blend of monomeric and polymeric species), with higher reactivity than IPDI and low viscosity, was added to the O phase to competitively contribute to the shell formation, improving its quality. Four different active H sources were tested, aimed at achieving a high encapsulation yield. The successful encapsulation of IPDI was confirmed by Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA), while the MCs’ morphology and size distribution were assessed by scanning electron microscopy (SEM). The incorporation of a multifunctional isocyanate silane in the O phase, as “latent” active H source, led to the formation of impermeable PUa/PU-silica hybrid shell MCs with more than 60 wt.% of pure encapsulated IPDI. A proof-of-concept study shows high peeling strength and a structural type of failure of the adhesive joint, revealing an effective IPDI release. These new engineered MCs are found to be promising crosslinkers for mono-component adhesives for high demanding applications.

Effect of Viscoelastic Property of Base Polymer on Extrusion Forming Caused By Thermally Expandable Microcapsules

One of recent requirements for automobile components is weight reduction for energy saving. Foam molding is a method of producing parts with reduced weight. Interior and exterior units made by utilizing chemical and physical foaming are in practical usage. However, due to the roughness of surface of foam molded parts, their usages are limited to hidden or painted components. In the present study, we focused on foam molding by using thermally expandable microcapsules. Thermally expandable microcapsules do not roughen surface of molded parts as the chemical or physical foaming does. The aim of the study is to elucidate influences of molding conditions such as temperature, shearing, resin properties, on microcapsule (MC) expansion behavior when MC foaming technology is used for foam molding of polypropylene (PP) which is one of general-purpose thermoplastics widely used for automobile components. The MC is a foaming agent of a fine particle containing a low boiling point hydrocarbon enclosed in a capsule of polymer material having gas barrier property. Heating the MC softens the polymer material of capsule shells. As the temperature rises, the vapor pressure of the contained hydrocarbon increases to expand capsules. For conventional molding with chemical or physical foaming, wall that supports void structure is made of base polymer. In this case viscoelastic properties of base polymer are required to keep void structure without collapse and breakage. Types of polymer is then limited to those that meet this requirement. Whereas for the case of MC foam molding, the capsule shells play a role of keeping bubble walls in base polymer. Choice of base polymer for the case of MC foaming is more flexible than for the case of conventional foam molding. In the present study, we examined foam molding of various types of PP using MC. We used four different types of homo PP and two types of block-copolymerized PP for base PPs of different MFRs. MC was added to each PP so that its concentration became 0.7% of total weight. Extrusion foam molding was carried out using a twin-screw extruder (Technovel Corporation KZW-30 ). The molding temperature was 200 °C or 240 °C. Foam molded structure was observed by using a scanning electron microscope. Average diameter of MC in PP was calculated from analysis of obtained images. The average diameter of MC was used to characterize efficiency of the present MC foam molding. The MFR of base PPs was evaluated at 230 ºC. From the present experimental results, it was found that the MC average diameter increases as the MFR of the base polymer increases. For the case of molding temperature 200ºC we saw saturation behavior of MC average diameter depending on MFR. These results are explained by a fact that when the molding temperature was low, the capsule shell of the MC was not so soft for enough expansion in base PP. In general, viscosity of polymer material depends on shear rate. In order to evaluate the influence of actual viscosity for molding in the extruder we measured shear viscosity of base polymers at shear rate of 314 s-1, which was estimated as a typical shear rate in the extruder. Measurement of the shear viscosity was performed by using a capillary rheometer (INSTRON SR50). Figure 1 shows the mean MC diameter depending on the shear viscosity. Molding temperature and viscosity measurement temperature were set at 240 °C. As the shear viscosity of the base polymer increased, the MC average diameter decreased. Present results of the MC average diameter depending on MFR and shear viscosity indicate that efficiency of MC foam molding actually depends on rheological properties of base polymer. We expect that a MC in the extrusion molding process expands under pressure from base polymer in shear deformation, and stops expanding on solidification of surrounding base polymer by cooling. Therefore, high shear viscosity of base polymer delays MC expansion before the solidification. In conclusion, it became clear that the expansion property of MC is tunable by changing viscosity of PP. Figure 1

Sugar Beet Artificial Seeds an Overview

Artificial seed propagation of crops broadens the horizon of plant biotechnology and farming. The technology offers techniques for micropropagulated seed analogs such as axillary leaves, embryogenic calli, somatic embryos, apical shoot tips, and protocorm-like organs. Micropropagules are embedded in gelling medium and carboxyl methyl cellulose active coatings. A variety of plant species, such as mulberry, sandalwood, cardamom, banana, sugar beet, maize, and relative, have recorded encapsulation of micro shoots and somatic embryos and subsequent recovery of full plantlets. This knowledge has shown that artificial seed manufacturing is possibly helpful for the propagation of economically significant species ' inferior hybrids on a big scale. Artificial seed development can only succeed with effective upstream manufacturing of micropropagules and downstream germination procedures for an elevated proportion of plant regeneration as one of the significant value-added plant tissue culture goods. Different micropropagules were regarded for the manufacturing of artificial seeds; however, mostly favored were somatic embryos and axillary stem buds. As micropropagules, somatic embryos were used to create artificial seeds in a wide range of fruit and plant organisms, which include Daucus carota, Picea abies, Arachis hypogaea, Medicago sativa, Psidium guajava, and Vitis vinifera. The review illustrated the concept of synthetic seeds and encapsulation procedure of sugar beet

Microencapsulation of a Staphylococcus phage for concentration and long-term storage

In an effort to reduce food safety risks, virulent phages are investigated as antibacterial agents for the control of foodborne pathogens. The aim of this study was to evaluate microencapsulation (ME) as a tool to concentrate and store staphylococcal bacteriophages. As a proof of concept, phage Team1 belonging to the Myoviridae family was microencapsulated in alginate gel particles of 0.5 mm (micro-beads) and 2 mm (macro-beads) of diameter. Gel contraction occurred during the hardening period in the CaCl2 solution, and the diameters of the initial alginate droplets shrunk by 16% (micro-beads) and 44% (micro-beads). As compared to the phage counts in the alginate solution, this contraction resulted in the increase of the phage titers, per g of alginate gel, by factors of 2 (micro-beads) and 6 (micro-beads). The encapsulation yield was highest in the macro-beads. Although phage Team1 was successfully frozen in beads, ME did not improve phage stability to freeze-drying. The addition of glycerol protected the microencapsulated phages during freezing but had no effect on free phage suspensions. Finally, ME improved storage stability at 4 °C but had no impact on freezing or drying over three months of storage.

Two-stage controlled release system possesses excellent initial and long-term efficacy.

In this work, a series of polyurea-based lambda-cyhalothrin-loaded microcapsules (MCs) with three different size distributions (average diameters of 1.35 μm, MC-S; 5.13 μm, MC-M; and 21.48 μm, MC-L) were prepared and characterized. The results indicated that MCs with a smaller particle size distribution had a faster release rate and excellent initial efficacy against pests. MC-L had a remarkably slow incipient release rate, outstanding photostability and better later-stage efficacy than that of the other tested MCs. The results clarified that the diameter distribution of MCs is the key factor in determining the release property and bioactivity of the MC formulations. Subsequently, the binary mixture MC formulations of MC(+M), MC(S+L) and MC(M+L) were obtained by mixing MC-S, MC-M or MC-L at 1:1 to establish a two-stage release system utilized for foliar application situations. Greenhouse and field experiments showed that MC(S+L) provided an optimal efficacy, and its effective duration was much longer than that of the emulsifiable concentrate (EC) group. Therefore, the release system established in this study was simple and workable for regulating the initial and long-term efficacy by adjusting the particle size distribution; in addition, this system has potential applications in other fields such as drug delivery devices.

Bacteriophage cocktail for biocontrol of Escherichia coli O157:H7: Stability and potential allergenicity study.

Escherichia coli O157:H7 has become a global public health and a food safety problem. Despite the implementation of control strategies that guarantee the safety in various products, outbreaks persist and new alternatives are necessary to reduce this pathogen along the food chain. Recently, our group isolated and characterised lytic bacteriophages against E. coli O157:H7 with potential to be used as biocontrol agents in food. To this end, phages need certain requirements to allow their manufacture and application. The aim of this study was to determine the physical stability and allergenic potential of free and microencapsulated (ME) bacteriophage cocktails against E. coli O157:H7. In vitro and in vivo studies were performed to determine phage survival under different pH, gastrointestinal conditions, temperature and UV light intensities. Results showed that the stability of ME phages was significantly (P<0.05) higher than free phages after ultraviolet irradiation, pH conditions between 3 to 7, and exposure to temperatures between at -80°C and 70°C. Both formulations were highly sensitive to very low pH in simulated gastric fluid, but stable in bile salts. In vivo studies in mice confirmed these phages passed through the gastrointestinal tract and were excreted in faeces. In silico, full-length alignment analysis showed that all phage proteins were negative for allergenic potential, but different predicting criteria classified seven phage proteins with a very low probability to be an allergen. In conclusion, these data demonstrated that microencapsulation provided a greater stability to phage formulation under stress conditions and assure a more suitable commercial formulation for the biological control of E. coli O157:H7.

Encapsulation of linseed oil and linseed oil based alkyd resin by urea formaldehyde shell for self-healing systems

In the present study, linseed oil based alkyd resin and linseed oil have been encapsulated to propose the alkyd resin as a prospective material for being used in epoxy coating system for corrosion protection through self-healing.The superiority of the present systems as Linseed oil and its alkyd resin evolves from the utilization of the environmentally friendliness thanks to their film formation by auto-oxidation. The encapsulation of healing agents by means of in-situ polymerization of urea formaldehyde has been studied with the parameters as the amount of surfactant and the rate of stirring. The experimental design has been modeled by using Response Surface Method to investigate the effect of surfactant (poly(vinyl alcohol), PVA) amount and stirring rate effect on the microcapsules (MC) size. Optical microscopy has been utilized to follow the reaction and size change of MCs. The chemical structure, thermal properties and capsule morphology has been illuminated by using FTIR spectroscopy, TGA and SEM analysis, respectively. The capsules obtained have had 51 and 56 μm diameter at high levels of the parameters (60 ml PVA, 1500 rpm stirring rate) and 97 and 261 μm diameter at low levels of the parameters (20 ml PVA, 800 rpm stirring rate) for LO and LO-Alkyd respectively.

Functionalized carbon nanotube reinforced polymer nanocomposite microcapsules with enhanced stiffness

Microcapsules with tunable mechanical properties are highly desirable in pressure sensitive applications. We report here a facile approach to prepare polyurea/multiwall carbon nanotube (MWCNTs) nanocomposite microcapsules (MICs) with enhanced stiffness. A model compound dimethyl phthalate (DMP) was used as core material. MWCNTs were modified with reactive functional groups namely carboxyl (COOH), amines (NH2), and isocyanates (NCO) to ensure a stronger interface between polymer wall and MWCNTs. Functionalization of MWCNTs was corroborated by Fourier transformed infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was employed to study the surface morphology of MICs. The presence of MWCNTs in the microcapsule wall was confirmed by transmission electron microscopy (TEM). MICs with functionalized MWCNTs show almost 100% increase in stiffness with respect to pristine capsules. All MICs show 92–97 ± 1% encapsulation efficiency. The approach used in this paper can be broadly utilized to tune the mechanical properties of the microcapsules.

Self-healing performance of an epoxy coating containing microencapsulated alkyd resin based on coconut oil

The microcapsules (MCs) containing alkyd resin based on coconut oil with different concentrations: 5, 10, and 15% were incorporated into a commercial epoxy coating and the coating was then applied on steel panel substrate. The effect of incorporation MCs on properties of the coatings was evaluated via assessment of surface roughness, gloss, adhesion strength, and bending elongation of the coatings containing MCs and comparing them with the properties of control coating. Furthermore, the healing performance in the epoxy coating and consequently their ability to protect the substrate against corrosion of the scratched coatings without and with MCs were also investigated in 5 wt% NaCl solution using potentiodynamic polarization tests and Electrochemical Impedance Spectroscopy (EIS). The obtained results revealed that increasing concentration of MCs in epoxy resin caused to a decrease in gloss and adhesion strength as well as a reduction in bending elongation of coatings. A good agreement between potentiodynamic polarization and EIS results indicated when the MCs concentration was equal to 10%, the amount of the released healing agent (alkyd resin based on coconut oil) was adequate to satisfactorily heal the cracks.

Near-infrared light-activatable siRNA delivery by microcapsules for combined tumour therapy

A polyelectrolyte microcapsule-based layer-by-layer (LbL) technique has been widely used as a multifunctional vehicle for combined tumor therapy. Meanwhile, with the rapid development of combined tumour therapy, the challenge for designing multifunctional drug delivery system has attracted much more attention. Herein, we developed a new type of microcapsule (MC) system called MPA@siRNA@DOX@MC, which conjugated with siRNA and DOX as well as ICG-Der-02 (MPA) by electrostatic absorption. MPA as indocyanine green (ICG) fluorescence dye, exhibiting high fluorescence emission and photothermal conversion ability under NIR laser irradiation, was uploaded onto this drug system for realizing the controllable drug release and cancer theranostics. In addition, the results revealed that MPA@siRNA@DOX@MC possessed several ideal properties including high drug-loading capacity, excellent siRNA transfection efficiency, siRNA sequence protection and remarkably improved tumour-targeting capacity. Moreover, the combined therapy based on this drug system displayed improved therapeutic efficacy and negligible side effects both in vivo and in vitro experiment. Ultimately, MPA@siRNA@DOX@MC drug delivery system successfully combined the photothermal therapy and chemotherapy with controlled siRNA sequence silencing may have a promising potential in combined tumor therapy.

Porous epoxy phenolic novolac resin polymer microcapsules: Tunable release and bioactivity controlled by epoxy value.

Microcapsules (MCs) prepared with diverse wall material structures may exhibit different properties. In this study, MCs were fabricated with three kinds of epoxy phenolic novolac resins (EPNs), which possessed unique epoxy values as wall-forming materials by interfacial polymerization. The effects of the EPN types on the surface morphology, particle size distribution, encapsulation efficiency, thermal stability as well as release behavior and bioactivity of the MCs were investigated. In all three samples, the MCs had nearly spherical shapes with fine monodispersities and sizes in the range of 7-30 μm. Scanning electron microscopy (SEM) images showed that some small pores (ranging from 50 nm to 400 nm) appeared on the microcapsule surfaces and that the porosity decreased with an increasing of epoxy value. The X-ray diffractometer (XRD) analysis indicated that the cured EPN shells had larger degrees of crosslinking with higher epoxy values, leading to better thermal stabilities. Moreover, the release rate of the core material (pendimethalin) decreased with an increasing of epoxy value and thus resulted in a lower herbicidal control efficacy. The results of our research will enhance the potential application of EPNs as smart wall-forming materials to prepare porous MCs for controlled release.

A New Method of Producing a Natural Antibacterial Peptide by Encapsulated Probiotics Internalized with Inulin Nanoparticles as Prebiotics.

Synbiotics are a combination of probiotics and prebiotics, which lead to synergistic benefits in host welfare. Probiotics have been used as an alternative to antibiotics. Among the probiotics, Pediococcus acidilactici (PA) has shown excellent antimicrobial activity against Salmonella Gallinarum (SG) as a major poultry pathogen and has improved the production performances of animals. Inulin is widely used as a prebiotic for the improvement of animal health and growth. The main aim of this study is to investigate the effect of the antimicrobial activity of inulin nanoparticles (INs)-internalized PA encapsulated into alginate/chitosan/alginate (ACA) microcapsules (MCs) in future in vivo application. The prepared phthalyl INs (PINs) were characterized by DLS and FE-SEM. The contents of phthal groups in phthalyl inulin were estimated by ¹H-NMR measurement as 25.1 mol.-%. The sizes of the PINs measured by DLS were approximately 203 nm. Internalization into PA was confirmed by confocal microscopy and flow cytometry. Antimicrobial activity of PIN-internalized probiotics encapsulated into ACA MCs was measured by co-culture antimicrobial assays on SG. PIN-internalized probiotics had a higher antimicrobial ability than that of ACA MCs loaded with PA/inulin or PA. Interestingly, when PINs were treated with PA and encapsulated into ACA MCs, as a natural antimicrobial peptide, pediocin was produced much more in the culture medium compared with other groups inulin-loaded ACA MCs and PA-encapsulated into ACA MCs.

Fungi extracellular enzyme-containing microcapsules enhance degradation of sulfonamide antibiotics in mangrove sediments.

Mangroves represent a special coastal vegetation along the coastlines of tropical and subtropical regions. Sulfonamide antibiotics (SAs) are the most commonly used antibiotics. The application of white-rot fungi extracellular enzyme-containing microcapsules (MC) for aerobic degradation of SAs in mangrove sediments was investigated in this study. Degradation of three SAs, sulfamethoxazole (SMX), sulfadimethoxine (SDM), and sulfamethazine (SMZ), was enhanced by adding MC to the sediments. The order of SA degradation in batch experiments was SMX > SDM > SMZ. Bioreactor experiments revealed that SA removal rates were higher with than without MC. The enhanced SA removal rates with MC persisted with three re-additions of SAs. Thirteen bacteria genera (Achromobacter, Acinetobacter, Alcaligenes, Aquamicrobium, Arthrobacter, Brevundimonas, Flavobacterium, Methylobacterium, Microbacterium, Oligotropha, Paracoccus, Pseudomonas, and Rhodococcus) were identified to be associated with SA degradation in mangrove sediments by combination of next-generation sequencing, bacterial strain isolation, and literature search results. Results of this study suggest that MC could be used for SA removal in mangrove sediments.

The role of radical polymerization in the production of thermoregulating microcapsules or polymers from saturated and unsaturated fatty acids

ABSTRACTThe microencapsulation of linoleic (LinA), oleic, erucic, and palmitic acids (PAs) from styrene and divinylbenzene were studied by using the suspension‐like polymerization technique. All materials exhibited a spherical shape, with a particle size between 166 and 416 μm. The phase change material (PCM) content decreased with the presence of double bonds in the fatty acid molecule. The thermal energy storage (TES) capacity of the microcapsules (MC) containing saturated PA was the highest (123.30 J g−1). Whereas, the lowest TES capacity was observed for the LinA. TES capacity values from unsaturated fatty acid materials and the high particle yield indicated that these kinds of acids played two different roles, as PCM and also as monomers, in the radical polymerization processes. At high initiator concentrations, the unsaturated fatty acids were observed to react. This was confirmed by Fourier transform infrared where the peak assigned to the CC bond disappears in the spectrum of MC. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45970.

Plasma-assisted deposition of microcapsule containing Aloe vera extract for cosmeto-textiles

Dielectric Barrier Discharge (DBD) atmospheric-pressure plasma was employed to enhance the deposition of commercial microcapsules (MCs) containing Aloe vera extract onto a cotton/polyester (50:50) fabric. DBD conditions were optimized in term of energy dosage and contact angle. The MCs were applied by padding and printing methods and the coatings were characterized in terms of SEM and FTIR. MCs display a spherical shape with size between 2 and 8 μm with an average wall thickness of 0.5 μm. The MCs applied by printing and pretreated with a plasma dosage of 1.6 kW m2 min-1 showed the best results with an increased adhesion of 200% and significant penetration of MCs into the fibres network. Plasma printed fabric retained 230% more MCs than untreated fabric after 10 washing cycles. However, the coating resistance between unwashed and washed samples was only improved by 5%. Considering the fact that no binder or crosslinking agents were used, the DBD plasma-assisted deposition of MCs revealed to be a promising environmental safe and low cost coating technology.

Optimization of alginate microcapsules containing cells overexpressing α-l-iduronidase using Box-Behnken design

Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease caused by deficiency of α-l-iduronidase (IDUA), which results in the lysosomal accumulation of glycosaminoglycans (GAG) leading to widespread clinical manifestations. The microencapsulation of IDUA overexpressing recombinant cells has been considered as a promising strategy for the treatment of MPS I. This study aimed at the optimization of alginate microcapsules containing recombinant BHK (Baby Hamster Kidney) cells (rBHK) overexpressing IDUA produced by electrostatic extrusion technique. The alginate microcapsule (MC-A) optimization study was carried out by means of an experimental Box-Behnken Design that allowed the simultaneous evaluation of the influence of voltage (kV), alginate/cell suspension flow (mL/h), and alginate concentration (%) on size and IDUA activity. The optimal conditions of voltage (10kV), flow (25mL/h), and alginate concentration (1.3%) made possible to obtain the smallest microcapsules showing the highest IDUA activity. After optimization, the microcapsules were sequentially coated with PLL and alginate (MC-APA) to increase their stability. MC-A and MC-APA presented monodisperse populations (span<1.22) with an average diameter of less than 350μm. The coating increased the mechanical stability of MC-APA by about 6-fold and modulated the permeability to the enzyme. Surface analyzes of MC-APA showed the presence of PLL bands, suggesting that the last alginate layer appears to have only partially coated the PLL. After 30days of subcutaneous implantation of the MC-APA microcapsules containing rBHK cells in a MPS I murine model, a significant increase in IDUA activity was observed in the skin near the implant. Histological analysis revealed an inflammatory infiltrate at the application site, which did not prevent the release of the enzyme under the conditions evaluated. Taken together, the overall results demonstrate the feasibility of MC-APA as a potential alternative for local treatment of MPS I.

Research progress of the cell microencapsulation

Cell microencapsulation aims to wrap the living target cells by one or several materials with good biological compatibility and semipermeable membrane properties. Cell microencapsulation not only can achieve immune isolation and prevent the attacks by macromolecular immunes and immune cells, but also can allow the free access of metabolites, small molecule nutrients and bioactive substances to the microcapsule. With the continuous progress of interdisciplinary technologies, cell microencapsulation shows increasing application prospects of making up a variety of limitations of organ transplantation. Moreover, with the development and maturation of cell microencapsulation, it has shown a strong advantage in regenerative medicine, which will certainly promote the rapid development of artificial cells and artificial organs. In this paper, the preparation of cell microcapsules, the effects of the outer membrane of microcapsules on immunological macromolecules and cytokines, the immunogenicity of the outer membrane, and the representative applications of cell microencapsulation were summarized. Key words: Cell microencapsulation; Immune isolation; Cytokines; Organ transplantation

Neural networks modeling of Aspergillus flavus growth in tomato paste containing microencapsulated olive leaf extract

AbstractOur aim was to incorporate olive leaf extract in both microencapsulated (ME) and nonencapsulated (NE) forms into tomato paste to get benefit from antimicrobial properties of the extract. Response variables were diametrical growth of Aspergillus flavus, total soluble solids (TSS), pH, and color indices of inoculated tomato paste. NE was more successful than ME to restrict growth of the fungus at both temperatures of 25 and 30 °C. Although the rate of TSS decreasing over the storage time was higher for ME samples than NE ones, but it remained constant for ME samples at the end of storage; TSS index of ME samples at 25 °C was kept unchanged for four final days of storage. Also, ME olive leaf extract could stabilize pH index equal to 4.75 (at 10th day of storage at 30 °C) for the rest of storage. ME samples enjoyed higher a* values than NE samples during storage at 30 °C. Considering fitting indices, Feed‐Forward‐Back‐Propagation network, Levenberg–Marquardt training algorithm, hyperbolic tangent sigmoid transfer function with 3‐5‐6 and 3‐6‐6 topologies represented the best artificial neural network models to predict both physicochemical and microbial properties of ME and NE samples when inoculated by A. flavus, respectively.Practical applicationsAntimicrobial properties of herbs and spices have been recognized for several years. Natural herbs or spices tend to lose their efficiency and fail to release their beneficial effects evenly over a longtime period. Simultaneously, it has been proved that microencapsulation is able to build a barrier between components of particles and their environment. Thus, it might be applied for olive leaf extract to keep favorable properties of tomato paste. Our aim was to incorporate microencapsulated (ME) olive leaf extract into tomato paste to get benefit from antimicrobial properties of the extract (against Aspergillus flavus) over short and longtime storage. Also, our another objective was to model the physicochemical and fungal changes within tomato paste containing nonencapsulated and ME olive leaf extract for the first time.