Non-encapsulated Ones Research Articles

Alginate–Poly[2-(methacryloyloxy)ethyl]trimethylammonium Chloride (PMETAC) Immunoisolating Capsules Prolong the Viability of Pancreatic Islets In Vivo

Background/Objectives: This study focuses on the development and evaluation of novel alginate–poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) microcapsules for encapsulating pancreatic islets to address insulin deficiency in diabetes. Methods: In previous research, we fabricated and characterized PMETAC microcapsules, evaluating their stability and permeability in vitro. This study further probes the capsules in vivo, focusing on the functional activity of the encapsulated islets post-transplantation, their viability extension, and the assessment of the immunoprotective, antifibrotic properties, and biostability of the capsules. Results: Rabbit-derived islets were encapsulated and transplanted into diabetic rats. The encapsulated islets maintained insulin secretion for up to 90 days, significantly longer than non-encapsulated ones, which ceased functioning after 7 days. Histological analysis demonstrated high biocompatibility of the PMETAC coating, resulting in minimal fibrotic overgrowth around the capsules. Conclusions: The study highlights the critical role of immunoprotection and the tendency to reduce fibrosis in prolonging islet function. These findings suggest that PMETAC-coated capsules offer a promising solution for cell-based therapies in diabetes by improving graft longevity and reducing fibrotic overgrowth.

Enhanced gut microbiota delivery of a model probiotic (Faecalibacterium prausnitzii): Layer-by-layer encapsulation using riboflavin-conjugated sodium alginate and glycol chitosan

Faecalibacterium prausnitzii (F. prausnitzii) exhibits a variety of biological functions that make it suitable for use as a next-generation probiotic. However, its high sensitivity to oxygen and digestive fluids currently limits its application. Riboflavin is known to support the growth of F. prausnitzii in oxygen environments, but it is important that it is in close proximity to the probiotics. Layer-by-layer assembly can be used to form protective coatings around probiotics, which can protect them from adverse environmental conditions. Moreover, riboflavin can be conjugated to these coatings, thereby increasing its efficacy by bringing it close to probiotic surfaces. In this study, we therefore evaluated the potential of electrostatic layer-by-layer assembly to protect F. prausnitzii by coating them with riboflavin-alginate and glycol-chitosan layers. Initially, we showed that riboflavin could be successfully conjugated to alginate, with a grafting ratio of around 4.35%. Then, the layer-by-layer method was used to coat F. prausnitzii using cationic glycol chitosan and anionic riboflavin-alginate. The coating formed was found to have a thickness of approximately 18.5 nm. Encapsulation did not adversely affect the growth of F. prausnitzii, but it significantly enhanced its resistance to oxygen and digestive fluids. The encapsulated probiotic was shown to have enhanced mucoadhesive properties using an in vitro intestinal monolayer model. Furthermore, the encapsulated probiotics colonized the colons of rats for longer than nonencapsulated ones. These results show that coating F. prausnitzii with riboflavin-rich biopolymer layers improves its resistance to oxygen and digestive fluids, and enhances its mucoadhesion and colonization properties, which should enhance its potential as an orally administered probiotic.

Oil-Based Double Emulsion Microcarriers for Enhanced Stability and Bioaccessibility of Betalains and Phenolic Compounds from Opuntia stricta var. dillenii Green Extracts.

Opuntia cactus fruit (prickly pear flesh and agricultural residues such as peels and stalks) is an important source of bioactive compounds, including betalains and phenolic compounds. In this work, two double emulsion W1/O/W2 formulations (A and B) were designed to encapsulate green extracts rich in betalains and phenolic compounds obtained from Opuntia stricta var. dillenii (OPD) fruits with the aim of improving their stability and protecting them during the in vitro gastrointestinal digestion process. In addition, the characterization of the double emulsions was studied by microscopy and the evaluation of their physical and physico-chemical parameters. Formulation A, based on Tween 20, showed smaller droplets (1.75 µm) and a higher physical stability than Formulation B, which was achieved with sodium caseinate (29.03 µm). Regarding the encapsulation efficiency of the individual bioactives, betalains showed the highest values (73.7 ± 6.7 to 96.9 ± 3.3%), followed by flavonoids (68.2 ± 5.9 to 95.9 ± 7.7%) and piscidic acid (71 ± 1.3 to 70.2 ± 5.7%) depending on the formulation and the bioactive compound. In vitro digestive stability and bioaccessibility of the individual bioactives increased when extracts were encapsulated for both formulations (67.1 to 253.1%) in comparison with the non-encapsulated ones (30.1 to 64.3%), except for neobetanin. Both formulations could be considered as appropriate microcarrier systems for green OPD extracts, especially formulation A. Further studies need to be conducted about the incorporation of these formulations to develop healthier foods.

Immunomodulatory and Antioxidant Effects of Spray-Dried Encapsulated Kale Sprouts after In Vitro Gastrointestinal Digestion.

The health-related compounds present in kale are vulnerable to the digestive process or storage conditions. Encapsulation has become an alternative for their protection and takes advantage of their biological activity. In this study, 7-day-old Red Russian kale sprouts grown in the presence of selenium (Se) and sulfur (S) were spray-dried with maltodextrin to assess their capacity to protect kale sprout phytochemicals from degradation during the digestion process. Analyses were conducted on the encapsulation efficiency, particle morphology, and storage stability. Mouse macrophages (Raw 264.7) and human intestinal cells (Caco-2) were used to assess the effect of the intestinal-digested fraction of the encapsulated kale sprout extracts on the cellular antioxidant capacity, the production of nitric oxide (NOx), and the concentrations of different cytokines as indicators of the immunological response. The highest encapsulation efficiency was observed in capsules with a 50:50 proportion of the hydroalcoholic extract of kale and maltodextrin. Gastrointestinal digestion affected compounds' content in encapsulated and non-encapsulated kale sprouts. Spray-dried encapsulation reduced the phytochemicals' degradation during storage, and the kale sprouts germinated with S and Se showed less degradation of lutein (35.6%, 28.2%), glucosinolates (15.4%, 18.9%), and phenolic compounds (20.3%, 25.7%), compared to non-encapsulated ones, respectively. S-encapsulates exerted the highest cellular antioxidant activity (94.2%) and immunomodulatory activity by stimulating IL-10 production (88.9%) and COX-2 (84.1%) and NOx (92.2%) inhibition. Thus, encapsulation is an effective method to improve kale sprout phytochemicals' stability and bioactivity during storage and metabolism.

Immunomodulatory Effects of Spherical Date Seed Pills Industrially Fabricated on RAW264.7 Cells

Dates have been demonstrated to display a variety of bioactivities and are rich in polyphenols. In this work, we assessed the underlying immunomodulatory effects of date seed polyphenol extracts that had been industrially encapsulated and fabricated into commercial pills in RAW264.7 macrophages using the NF-κB and Nrf2 signaling pathways. The outcomes showed that in RAW264.7 cells, the date seed pills effectively stimulated nuclear translocation of NF-E2-related factor 2 (Nrf2) and NF-κB, along with downstream cytokines (IL-1β, TNF-α, IL-6, and IFN-γ), ROS ratios, and SOD activity. It is interesting to note that the encapsulated pills activated Nrf2 nuclear translocation more effectively than the non-encapsulated ones did. Additionally, pills at 50 µg mL-1 improved immunological responses, but pills at 1000 µg mL-1 prevented macrophages from becoming inflamed. These results showed that the immunomodulatory effects were differently impacted by commercial date seed pills, a finding which was related to the large-scale manufacturing of the pills and the incubation concentrations used. These results also shed light on a new trend of using food byproducts as an innovative supplement.

Injectable and self-healing hydrogel as a stem cells carrier for treatment of diabetic erectile dysfunction.

Diabetic erectile dysfunction has witnessed extensive preclinical and clinical explorations of intracavernous injection of stem cells therapy. However, intracavernous injection of stem cells for diabetic erectile dysfunction is challenged by rapid diffusion from cavernous sinus. Here, we found that a benzaldehyde terminated poly (ethylene glycol)/glycol chitosan (CHO-PEG/GCS) hydrogel with injectability and self-healability served as a stem cell carrier to prolong cell retention in corpus cavernosum. It was able to gelate under physiological condition and encapsulate adipose stem cells (ASCs) without reducing proliferation after injection. Encapsulated labelled ASCs presented higher fluorescence than non-encapsulated ones in the region of penis at 14days after intracavernous injection in male rats. CHO-PEG/GCS hydrogel enhanced ASCs to ameliorate diabetes-induced fibrosis and apoptosis of CD31-positive endothelial cells, α-SMA-positive smooth muscle and NeuN-positive neural fibers 12weeks post-operation. It also synergized with ASCs to elevate cGMP level and promote erectile function. CHO-PEG/GCS hydrogel serves as a promising stem cell carrier in conditions requiring injection and in situ gelation to prolong cell retention.

Growth and survival of microencapsulated probiotics prepared by emulsion and internal gelation

Efficient microencapsulation of probiotics by most existing methods is limited by low throughput. In this work, Saccharomyces boulardii and Enterococcus faecium were microencapsulated by a method based on emulsion and internal gelation. The growth and survival of microencapsulated microbes under different stressors were investigated using free non-encapsulated ones as a control. The results showed that the prepared micro-beads by emulsion and internal gelation exhibited a spherical and smooth shape, with sizes between 300 and 500 μm. Both S. boulardii and E. faecium grew well and survived better when encapsulated in micro-beads. The survival rates were increased 25% and 40% for microencapsulated S. boulardii and E. faecium respectively when compared with non-encapsulated controls under high temperature and high humidity. The increases of survival rates were 60% for microencapsulated S. boulardii and 25% for E. faecium in simulated gastric juice. And the increases were 15% and 20% respectively when the survival rates of the microencapsulated S. boulardii and E. faecium were determined in simulated intestinal juice. The microencapsulation by emulsion and internal gelation offers an effective way to protect microbes in adverse in vitro and in vivo conditions and is promising for the large-scale production of probiotics microencapsulation.

Explant Type, Culture System, 6-Benzyladenine, Meta-Topolin and Encapsulation Affect Indirect Somatic Embryogenesis and Regeneration in Carica papaya L.

A protocol to propagate papaya hybrid plants through indirect somatic embryogenesis was developed considering the effect of explant type, culture system, particular cytokinins and encapsulation, in different stages of the process. Optimal 2,4-dichlorophenoxyacetic acid (2,4-D) concentrations for non-embryogenic callus formation ranged between 9.0 and 27.1 μM in half-cut seeds, while higher concentrations were harmful. Non-embryogenic callus was also obtained with 22–158 μM 2,4-D from hypocotyl segments. Callus with embryogenic structures was only obtained in half-cut seeds cultured in the darkness on half-strength Murashige and Skoog culture medium supplemented with 2,4-D, while hypocotyl segments and isolated zygotic embryos failed to produce this type of callus regardless of the 2,4-D and sucrose (30 and 70 g l-1) concentrations tested in this study. Both, embryogenic callus development and quantity of somatic embryos formed per embryogenic callus, which ranged between 11 and 31 units after 14 months, required 2,4-D, but without any effect of the concentration. Histological studies confirmed the multicellular origin of the somatic embryos. In further steps, liquid medium induced over four times more somatic embryos than agar-gelled medium and showed significantly higher production of globular somatic embryos (85 vs. 57%). Both, 6-benzyladenine (BA) and meta-topolin (Mtop) stimulated sprouting (40–45%) of the somatic embryos (development of shoots only) in concentrations of up to 2.7 and 10 μM, respectively. Sprouting probability showed a 2nd order polynomial trend despite the range of concentration used for each cytokinin. This is the first report about the positive effect of Mtop on the apical shoot development of Carica papaya somatic embryos known to the authors. Radicle growth was observed in 5% or less of the cultivated embryos, regardless of the BA concentration. Finally, all encapsulation conditions tested (2.5, 3.5, and 4.5% sodium alginate, combined with 50 and 100 mM CaCl2) reduced sprouting of somatic embryos when compared to the non-encapsulated ones, whereas capsule hardness showed low correlation with embryo sprouting. Embryos were further cultivated until they became plantlets approximately 5 cm long. They were acclimatized and afterward planted in the field, where they flowered and produced fruit.

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.

Development of structured natural dyes for use into plastics

This study aimed to identify whether natural dyes encapsulated in a silica matrix via the sol-gel process with the use of alkoxides (as described in INPI patent BR 10 2013 0219835) and subsequently injected into a polyvinyl chloride (PVC) matrix would preserve their original color characteristics after being subjected to Xenon-accelerated weathering (using the ASTM D4452-12 standard). A comparison was conducted of the same natural dyes - carmine, turmeric, indigo and annatto – with and without encapsulation, injected into the same PVC matrix. Color change measurements were made before the weathering test and after 126 h, 252 h, 378 h and 504 h in a Xenon weathering chamber using the ASTM D4459-12 standard. A non-encapsulated Tartrazine dye (INS 102, an azo dye) was used for comparison of the behavior of natural dyes vs. that of synthetic ones. The results pointed to a lack of discoloring protection for the encapsulated natural dyes, which lost saturation more severely than the non-encapsulated ones. It thus follows that some care is required during the encapsulation stages of natural dyes, such as careful dispersion of natural colorants and the inclusion of repeat stages for the encapsulation of the xerogel.

Modeling quality changes in tomato paste containing microencapsulated olive leaf extract by accelerated shelf life testing

In this research, Arrhenius equation accelerated shelf life testing (ASLT) were applied to predict color and pH indices of bulk tomato paste containing microencapsulated and non-encapsulated olive leaf extract. Seven samples of tomato paste containing 500 and 1000ppm non-encapsulated olive leaf extract (NC 500 and NC 1000), 500 and 1000ppm microencapsulated olive leaf extract (C 500 and C 1000), and 500 and 1000ppm sodium benzoate (B 500 and B 1000) along with control sample were prepared and investigated at three temperatures of 30, 40 and 50 (°C). Control and B 1000 samples, respectively yielded the highest (0.022day−1) and lowest (0.003day−1) rate constants for both color and pH change. In the case of pH and among different treatments, the lowest and highest activation energies, Ea were related to NC 500 and B 1000 samples, respectively; interestingly pH rate constants of encapsulated samples were higher than non-encapsulated ones and even higher than benzoate sample (only at the level of 500ppm). Also, ASLT procedure could estimate changes in color of C 500 and pH of C 1000 samples better than other samples (during storage time).

Antimicrobial Activity of Nano-Encapsulated Essential Oils: Comparison to Non-Encapsulated Essential Oils

As fragile active components, essential oils should be encapsulated to solve several problems linked to their use, including toxicity, miscibility in aqueous medium, time-controlled release, formulations or preparations for various industries (pharmaceuticals, cosmetics, textiles, chemicals, food, etc.). Then, the aim of this study is to perform nano-encapsulation of selected essential oils and to compare their antimicrobial activities with the non-encapsulated ones. Essential oils of Thymus leptobotrys, Thymus satureoides, Pelargonium graveolens, Eugenia Caryophyllata and their major component Eugenol were first encapsulated by the nanoprecipitation technique using Eudragit RS 100 as coating polymer. This results in a final stable milky dispersion of essential oils nanocapsules having a final concentration of 4% (v/v). The formed nanoparticles have 110 nm averages in diameter particle size and possess positive zeta potential (approximately 81 mV). Chemical composition of these encapsulated essential oils was investigated by Gas Chromatography-Mass Spectrometry confirming similarities to the non-encapsulated ones. Antimicrobial assays against five bacterial strains, two yeasts and two moulds, confirm that the prepared nanoparticles exhibit, at a comparative concentration of 0.4% (v/v), relatively less antimicrobial activities (both bacteriostatic and fungistatic) than the non-encapsulated EOs. These results lead us to think to numerous applications of such essential oils particularly in the pharmaceutical and cosmetic domains.

Encapsulation, protection, and release of polyunsaturated lipids using biopolymer-based hydrogel particles

Delivery systems are needed to encapsulate polyunsaturated lipids, protect them within food products, and ensure their bioavailability within the gastrointestinal tract. Hydrogel particles assembled from food-grade biopolymers are particularly suitable for this purpose. In this study, hydrogel microspheres were fabricated by electrostatic complexation of low methoxy pectin and caseinate by decreasing the solution pH from 7 to 4.5. After hydrogel particle formation, the caseinate was enzymatically cross-linked using transglutaminase to improve the stability of the biopolymer matrix. The effect of hydrogel particle encapsulation on the physical location, chemical stability, and lipase digestibility of emulsified polyunsaturated lipids (fish oil) was investigated. The cross-linked hydrogel particles formed using this process were relatively small (D43=4.6μm), negatively charged (ζ=−37mV), and evenly distributed within the system. Confocal microscopy confirmed that the fish oil droplets were trapped within casein-rich hydrogel microspheres. Encapsulation of the fish oil droplets improved their stability to lipid oxidation compared to conventional emulsions, which was attributed to a high local concentration of antioxidant protein around the emulsified lipids. The rate and extent of digestion of the encapsulated lipid droplets within a simulated small intestine were similar to those of non-encapsulated ones. These results suggest that casein-rich hydrogel microspheres may protect polyunsaturated lipids in foods and beverages, but release them after ingestion.

Cell immobilization of Streptomyces coelicolor : effect on differentiation and actinorhodin production.

Streptomycetes are mycelium-forming bacteria that produce two thirds of the clinically relevant secondary metabolites. Despite the fact that secondary metabolite production is activated at specific developmental stages of the Streptomyces spp. life cycle, different streptomycetes show different behaviors, and fermentation conditions need to be optimized for each specific strain and secondary metabolite. Cell-encapsulation constitutes an interesting alternative to classical fermentations, which was demonstrated to be useful in Streptomyces, but development under these conditions remained unexplored. In this work, the influence of cell-encapsulation in hyphae differentiation and actinorhodin production was explored in the model Streptomyces coelicolor strain. Encapsulation led to a delay in growth and to a reduction of mycelium density and cell death. The high proportion of viable hyphae duplicated extracellular actinorhodin production in the encapsulated cultures with respect to the non-encapsulated ones.

Direct spray drying and microencapsulation of probioticLactobacillus reuterifrom slurry fermentation with whey

Formulations of dietary probiotics have to be robust against process conditions and have to maintain a sufficient survival rate during gastric transit. To increase efficiency of the encapsulation process and the viability of applied bacteria, this study aimed at developing spray drying and encapsulation of Lactobacillus reuteri with whey directly from slurry fermentation. Lactobacillus reuteri was cultivated in watery 20% (w/v) whey solution with or without 0·5% (w/v) yeast extract supplementation in a submerged slurry fermentation. Growth enhancement with supplement was observed. Whey slurry containing c. 10(9) CFUg(-1) bacteria was directly spray-dried. Cell counts in achieved products decreased by 2 log cycles after drying and 1 log cycle during 4weeks of storage. Encapsulated bacteria were distinctively released in intestinal milieu. Survival rate of encapsulated bacteria was 32% higher compared with nonencapsulated ones exposed to artificial digestive juice. Probiotic L. reuteri proliferate in slurry fermentation with yeast-supplemented whey and enable a direct spray drying in whey. The resulting microcapsules remain stable during storage and reveal adequate survival in simulated gastric juices and a distinct release in intestinal juices. Exploiting whey as a bacterial substrate and encapsulation matrix within a coupled fermentation and spray-drying process offers an efficient option for industrial production of vital probiotics.

Encapsulation of sex sorted boar semen: Sperm membrane status and oocyte penetration parameters

Although sorted semen is experimentally used for artificial, intrauterine, and intratubal insemination and in vitro fertilization, its commercial application in swine species is still far from a reality. This is because of the low sort rate and the large number of sperm required for routine artificial insemination in the pig, compared with other production animals, and the greater susceptibility of porcine spermatozoa to stress induced by the different sex sorting steps and the postsorting handling protocols. The encapsulation technology could overcome this limitation in vivo, protecting and allowing the slow release of low-dose sorted semen. The aim of this work was to evaluate the impact of the encapsulation process on viability, acrosome integrity, and on the in vitro fertilizing potential of sorted boar semen. Our results indicate that the encapsulation technique does not damage boar sorted semen; in fact, during a 72-hour storage, no differences were observed between liquid-stored sorted semen and encapsulated sorted semen in terms of plasma membrane (39.98 ± 14.38% vs. 44.32 ± 11.72%, respectively) and acrosome integrity (74.32 ± 12.17% vs. 66.07 ± 10.83%, respectively). Encapsulated sorted spermatozoa presented a lower penetration potential than nonencapsulated ones (47.02% vs. 24.57%, respectively, P < 0.0001), and a significant reduction of polyspermic fertilization (60.76% vs. 36.43%, respectively, polyspermic ova/total ova; P < 0.0001). However, no difference (P > 0.05) was observed in terms of total efficiency of fertilization expressed as normospermic oocytes/total oocytes (18.45% vs. 15.43% for sorted diluted and sorted encapsulated semen, respectively). The encapsulation could be an alternative method of storing of pig sex sorted spermatozoa and is potentially a promising technique in order to optimize the use of low dose of sexed spermatozoa in vivo.

Structure and function of macroencapsulated human and rodent pancreatic islets transplanted into nude mice.

Macroencapsulation of human pancreatic islets inside biomembranes is a promising approach to maintain islet allografts in the diabetic recipient without immunosuppression. In order to test this possibility islets isolated from human pancreata were kept in culture before macroencapsulation in a tissue chamber device. The device consisted of two titanium rings, which supported two flat membranes. These membranes have previously been shown to protect pancreatic islets and fetal lung tissue from allograft rejection and also to promote neovascularization at the membrane surface. In a first series of experiments macroencapsulated human islets were implanted into the epididymal fat pad of athymic, nude mice concomitant to an injection from the same batch of islets under the kidney capsule. Light microscopy of encapsulated and subcapsularly grafted human islets showed that the survival inside the membranes was as good as under the kidney capsule. There was an extensive formation of new blood vessels at the membrane outer surface. In a second series of experiments insulin was extracted from encapsulated human islets implanted either into the epididymal fat pad or subcutaneously. The encapsulated human islets contained as much insulin as the non-encapsulated ones. In these experiments mouse and rat islets were also used. Rodent islets, however, survived less well than the human islets as evidenced by the markedly reduced insulin content values. In a third series of experiments human islets were loaded into the chambers and transplanted into nude mice without the concomitant implantation of non-encapsulated islets under the kidney capsule of the recipienets. Measurements of human C-peptide in serum samples obtained 4 to 8 weeks post-implantation showed considerable concentrations (0.70-185 ng/ml) in all animals. We conclude that isolated human islets survive when implanted into nude mice and continue to release insulin for several weeks. There are, however, species differences suggesting that rodent islets are much more susceptible to the environmental stress inside the membranes than human islets.