Alginate-chitosan Microcapsules Research Articles

Microencapsulation and sonication: A multiple physical approach to attenuate the probiotic Lacticaseibacillus casei ATCC 393

Modulation of probiotic performances represents a tool to avoid the probiotic off-flavor in probiotic food. Microencapsulation and sonication were evaluated in slowing down the Lacticaseibacillus casei ATCC 393 induced acidification. Firstly, the influence of alginate concentration and chitosan coating on acidification rate were tested. Microcapsule morphology and the entrapment efficacy were also evaluated. Then, two time of exposure to ultrasound, 6 and 8 min, were applied for L. casei attenuation. Finally, sonicated cells were encapsulated. ΔpH after 6 and 24 h of incubation at 37 °C revealed that chitosan-alginate microcapsules and the 8-min sonicated probiotic presented a significant delayed acidification. When all the systems were compared, the encapsulation of 8-min sonicated L. casei in chitosan-alginate microcapsules significantly improved the results obtained with the single technologies. These results suggest that by modulating the operating parameters and combining these two technologies an increasingly efficient attenuation system can be developed.

Improved membrane stability of alginate-chitosan microcapsules by crosslinking with tannic acid.

The insufficient stability of alginate-chitosan (ALG-CS) microcapsules in biorelevant media limits their applications in the biomedical field. Attempts were made to improve the membrane stability of ALG-CS microcapsules by noncovalent crosslinking with tannic acid. The membrane stability of ALG-CS microcapsules in culture medium and serum was significantly improved by crosslinking with tannic acid. Moreover, the reason for the significant improvement in membrane stability had been demonstrated to be that the stability of chitosan-tannic acid (CS-TA) polyelectrolyte complexes was less affected by the competitive binding of those weak acid ions such as HCO3-. In addition, the optimal conditions for preparing alginate-chitosan-tannic acid (ALG-CS-TA) microcapsules were tannic acid concentration of 0.5% (w/v) and pH = 7. The study provides a novel approach for improving the stability of the ALG-CS microcapsules in biorelevant media to expand their scope of application in the biological field.

Shell engineering in soft alginate-based capsules for culturing liver spheroids.

Functional interaction between cancer cells and the surrounding microenvironment is still not sufficiently understood, which motivates the tremendous interest for the development of numerous in vitro tumor models. Diverse parameters, for example, transport of nutrients and metabolites, availability of space in the confinement, etc. make an impact on the size, shape, and metabolism of the tumoroids. We demonstrate the fluidics-based low-cost methodology to reproducibly generate the alginate and alginate-chitosan microcapsules and apply it to grow human hepatoma (HepG2) spheroids of different dimensions and geometries. Focusing specifically on the composition and thickness of the hydrogel shell, permeability of the microcapsules was selectively tuned. The diffusion of the selected benchmark molecules through the shell has been systematically investigated using both, experiments and simulations, which is essential to ensure efficient mass transfer and/or filtering of the biochemical species. Metabolic activity of spheroids in microcapsules was confirmed by tracking the turnover of testosterone to androstenedione with chromatography studies in a metabolic assay. Depending on available space, phenotypically different 3D cell assemblies have been observed inside the capsules, varying in the tightness of cell aggregations and their shapes. Conclusively, we believe that our system with the facile tuning of the shell thickness and permeability, represents a promising platform for studying the formation of cancer spheroids and their functional interaction with the surrounding microenvironment.

The Oral Inactivated Porcine Epidemic Diarrhea Virus Presenting in the Intestine Induces Mucosal Immunity in Mice with Alginate–Chitosan Microcapsules

The porcine epidemic diarrhea virus, PEDV, which causes diarrhea, vomiting and death in piglets, causes huge economic losses. Therefore, understanding how to induce mucosal immune responses in piglets is essential in the mechanism and application against PEDV infection with mucosal immunity. A method of treatment in our research was used to make an oral vaccine that packaged the inactive PEDV with microencapsulation, which consisted of sodium alginate and chitosan, and adapted the condition of the gut in mice. The in vitro release experiment of microcapsules showed that inactive PEDV was not only easily released in saline and acid solutions but also had an excellent storage tolerance, and was suitable for use as an oral vaccine. Interestingly, both experimental groups with different doses of inactive virus enhanced the secretion of specific antibodies in the serum and intestinal mucus, which caused the effective neutralization against PEDV in the Vero cell by both IgG and IgA, respectively. Moreover, the microencapsulation could stimulate the differentiation of CD11b+ and CD11c+ dendritic cells, which means that the microencapsulation was also identified as an oral adjuvant to help phagocytosis of dendritic cells in mice. Flow cytometry revealed that the B220+ and CD23+ of the B cells could significantly increase antibody production with the stimulation from the antigens' PEDV groups, and the microencapsulation could also increase the cell viability of B cells, stimulating the secretion of antibodies such as IgG and IgA in mice. In addition, the microencapsulation promoted the expression of anti-inflammatory cytokines, such as IL-10 and TGF-β. Moreover, proinflammatory cytokines, such as IL-1, TNF-α, and IL-17, were inhibited by alginate and chitosan in the microencapsulation groups compared with the inactivated PEDV group. Taken together, our results demonstrate that the microparticle could play the role of mucosal adjuvant, and release inactivated PEDV in the gut, which can effectively stimulate mucosal and systemic immune responses in mice.

Oral Lactobacillus casei expressing VP56310–500 and adjuvant flagellin C delivered by alginate-chitosan microcapsules remarkably enhances the immune protection against GCRV infection in grass carp

Due to grass carp haemorrhagic disease caused by grass carp reovirus (GCRV), aquaculture industry suffers huge economic loss. Oral Lactobacillus casei vaccine, with its excellent safety and effectiveness, is a promising strategy to prevent infectious diseases. While, the oral vaccine encapsulated with alginate–chitosan (SA/CS) can further improve its immune function. In this study, recombinant L. casei (rLc) expressing multiple fragments of VP56 was constructed, which was a key outer capsid protein of GCRV. By mixing rLcs with fodder and fed grass carp, the corresponding anti-VP56 fragment sera was produced, and VP56310–500 was screened as optimal fragment of GCRV-II by adopting enzyme linked immunosorbent assay (ELISA). Furthermore, SA/CS was used as the encapsulating material of L. casei live vaccine expressing VP56310–500, thereby preparing oral microcapsule live vaccine SCL-56310-500. With good resistance to bile (0–0.4%), NaCl (0–0.8%), simulated intestinal fluid, and simulated gastric fluid (pH = 1.5–4.5). Also, it had the ability to maintain high viability after colonizing intestine of grass carp in 7 days. In addition, Flagellin C (FlaC) was adopted as an immune adjuvant, and rLc was constructed to express VP56310–500-FlaC (56310–500C), thereby enhancing immune effect of oral live vaccine. After oral administration of encapsulated L. casei vaccine, its protective effect on GCRV-II infection was evaluated. As indicated by the results, SCL-56310-500C effectively up-regulated the activity of serum biochemical enzymes (including TSOD, lysozyme, and complement C3), and induced mRNA expression of important immune genes (including IL-1β, IFN1, MHC-IIα, IgM, and IgT in immune tissues). Simultaneously, SCL-56310-500C greatly suppressed GCRV replication in head kidney, spleen, and intestine. Correspondingly, grass carp vaccinated orally with SCL-56310-500C have distinctly higher survival rate (58% versus 24% in control) against GCRV infection. These results illustrated that an oral probiotic vaccine SCL-56310-500C effective in GCRV infection prevention was developed. Thus, this study offered an inspiring strategy for the prevention of fish viral diseases.

Oral Administration of Multistage Albumin Nanomedicine Depots (MANDs) for Targeted Efficient Alleviation of Chronic Inflammatory Diseases

AbstractMethotrexate (MTX) by oral taking has been employed as the first‐line medication for various chronic inflammatory diseases treatment, such as Crohn's disease and rheumatoid arthritis (RA). However, the oral administration of MTX has very limited clinical benefits and will be discontinued due to the suboptimal response and severe adverse effects on intestinal mucosa. Herein, a multistage albumin nanomedicine depot (denoted as MAND) is formulated by encapsulating MTX‐loaded human serum albumin nanoparticles (MTX@HSA NPs) into calcium alginate chitosan microcapsules using a gas‐shearing technology. The MANDs can provide protection to MTX@HSA NPs with well‐persisted biologic activity against gastric acid erosion and realize specific boost release of MTX@HSA NPs in the intestinal tract in response to the mild basic circumstance. The MTX@HSA NPs absorbed by intestine can selectively accumulate in inflammation lesion by exploiting the inflammation targeting ability of HSA. In the animal experiments, the MANDs show improved therapeutic efficacy for the treatment of both RA and colitis with minimized intestinal side effects in respect to the free MTX by oral administration. Therefore, this conceived oral MANDs can promote a more clinic popularity and enhanced benefits of MTX for the treatment of chronic inflammatory diseases.

Physicochemical properties of bone marrow mesenchymal stem cells encapsulated in microcapsules combined with calcium phosphate cement and their ectopic bone formation.

Calcium phosphate bone cement (CPC) serves as an excellent scaffold material for bone tissue engineering owing to its good biocompatibility, injectability, self-setting property and three-dimensional porous structure. However, its clinical use is limited due to the cytotoxic effect of its setting reaction on cells and difficulties in degradation into bone. In this study, bone marrow mesenchymal stem cells (BMSCs) were encapsulated in alginate chitosan alginate (ACA) microcapsules and compounded with calcium phosphate bone cement. Changes in the compressive strength, porosity, injectability and collapsibility of CPC at different volume ratios of microcapsules were evaluated. At a 40% volume ratio of microcapsules, the composite scaffold displayed high porosity and injectability with good collapsibility and compressive strength. Cell live/dead double staining, Cell Counting Kit-8 (CCK-8) assays and scanning electron microscopy were used to detect the viability, proliferation and adhesion of cells after cell microcapsules were combined with CPC. The results revealed that cells protected by microcapsules proliferated and adhered better than those that were directly combined with CPC paste, and cell microcapsules could effectively form macropores in scaffold material. The composite was subsequently implanted subcutaneously on the backs of nude mice, and ectopic osteogenesis of the scaffold was detected via haematoxylin-eosin (H&E), Masson’s trichrome and Goldner’s trichrome staining. CPC clearly displayed better new bone formation function and degradability after addition of pure microcapsules and cell microcapsules. Furthermore, the cell microcapsule treatment group showed greater osteogenesis than the pure microcapsule group. Collectively, these results indicate that BMSCs encapsulated in ACA microcapsules combined with CPC composite scaffolds have good application prospects as bone tissue engineering materials.

Enhanced survival of Lacticaseibacillus rhamnosus in simulated gastrointestinal conditions using layer-by-layer encapsulation

The release behavior of Lacticaseibacillus rhamnosus from single bilayer microcapsules of alginate-chitosan (AC) and its double bilayer (ACAC) was investigated in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Methods Multilayer polyelectrolyte AC microcapsules were fabricated using the layer-by-layer (LbL) self-assembly technique through electrostatic interactions. Results AC and ACAC microcapsules kept their integrity and mechanical stability in simulated gastric conditions. Bacterial cells remained inside microcapsules in SGF and dissolution of microcapsules was observed in SIF. To improve the bacterial survivability, L. rhamnosus was co-encapsulated in a double bilayer of AC hydrogels with calcium carbonate as an antacid agent. Conclusions The LbL self-assembly technology provides stable and target release for ACAC microcapsules. Therefore, the double bilayer polyelectrolyte microcapsules have a remarkable potential for successful application in the targeted and controlled delivery of different probiotics and drugs.

Alginate-Chitosan Microencapsulated Cells for Improving CD34+ Progenitor Maintenance and Expansion

Protocols for isolation, characterization, and transplantation of hematopoietic stem cells (HSCs) have been well established. However, difficulty in finding human leucocyte antigens (HLA)-matched donors and scarcity of HSCs are still the major obstacles of allogeneic transplantation. In this study, we developed a double-layered microcapsule to deliver paracrine factors from non-matched or low-matched HSCs to other cells. The umbilical cord blood-derived hematopoietic progenitor cells, identified as CD34+ cells, were entrapped in alginate polymer and further protected by chitosan coating. The microcapsules showed no toxicity for surrounding CD34+ cells. When CD34+ cells-loaded microcapsules were co-cultured with bare CD34+ cells that have been collected from unrelated donors, the microcapsules affected surrounding cells and increased the percentage of CD34+ cell population. This study is the first to report the potency of alginate-chitosan microcapsules containing non-HLA-matched cells for improving proliferation and progenitor maintenance of CD34+ cells.

Dual pH responsive via double - layered microencapsulation for controlled release of active ingredients in simulated gastrointestinal tract: A model case of chitosan-alginate microcapsules containing basil oil (Ocimum basilicum Linn.)

Phytogenic feed additives (PFAs) have gained more attention to replace antibiotic growth promoters (AGPs) in poultry industry. However, the efficiency of PEAs might be lost during feed pelleting, storage and gastrointestinal (GI) tract resulting in an insufficient level at the small intestine. The present work demonstrates the use of double-layered polymers with opposite charges leading to a dual pH responsiveness where the encapsulated ingredients are remained active through the acidic gastric stage and ready to be released at the intestine. Anionic sodium alginate (SA) and cationic chitosan (CS) are a good combination to represent double-layered polymer of which an effective incorporation of active ingredient, i.e. basil oil (BO), a model PEA, can be achieved. By simply fabricating SA porous microcapsules followed by the absorption of BO before the surface coating with CS, the double-layered microcapsules, CS-SA, are obtained. The release performances confirm that CS-SA retains the antioxidant and antimicrobial activities of BO under storage in addition to a great tolerance of acids, bile, trypsin, including the thermal conditions. The present work, for the first time, proposes the concept of porous double-layered polymer in microcapsule form which shows the dual pH responsive for controlled release application. The use of ionic polysaccharides is simple, biocompatible and environmentally friendly, whereas the plausible upscaling for wide range of controlled release applications has to be further investigated.

Suppression of Fibrotic Reactions of Chitosan-Alginate Microcapsules Containing Porcine Islets by Dexamethasone Surface Coating.

BackgroundThe microencapsulation is an ideal solution to overcome immune rejection without immunosuppressive treatment. Poor biocompatibility and small molecular antigens secreted from encapsulated islets induce fibrosis infiltration. Therefore, the aims of this study were to improve the biocompatibility of microcapsules by dexamethasone coating and to verify its effect after xenogeneic transplantation in a streptozotocin-induced diabetes mice.MethodsDexamethasone 21-phosphate (Dexa) was dissolved in 1% chitosan and was cross-linked with the alginate microcapsule surface. Insulin secretion and viability assays were performed 14 days after microencapsulation. Dexa-containing chitosan-coated alginate (Dexa-chitosan) or alginate microencapsulated porcine islets were transplanted into diabetic mice. The fibrosis infiltration score was calculated from the harvested microcapsules. The harvested microcapsules were stained with trichrome and for insulin and macrophages.ResultsNo significant differences in glucose-stimulated insulin secretion and islet viability were noted among naked, alginate, and Dexa-chitosan microencapsulated islets. After transplantation of microencapsulated porcine islets, nonfasting blood glucose were normalized in both the Dexa-chitosan and alginate groups until 231 days. The average glucose after transplantation were lower in the Dexa-chitosan group than the alginate group. Pericapsular fibrosis and inflammatory cell infiltration of microcapsules were significantly reduced in Dexa-chitosan compared with alginate microcapsules. Dithizone and insulin were positive in Dexa-chitosan capsules. Although fibrosis and macrophage infiltration was noted on the surface, some alginate microcapsules were stained with insulin.ConclusionDexa coating on microcapsules significantly suppressed the fibrotic reaction on the capsule surface after transplantation of xenogenic islets containing microcapsules without any harmful effects on the function and survival of the islets.

Alginate-chitosan microcapsules improve vaccine potential of gamma-irradiated Listeria monocytogenes against listeriosis in murine model

Listeria monocytogenes is a cause of infectious food-borne disease in humans, characterized by neurological manifestations, abortion, and neonatal septicemia. It is intracellular bacterium, which limits the development of protective inactivated vacines. Adjuvants capable of stimulating cellular immune response are important tools for developing novel vaccines against intracellular bacteria. The aim of this study was to evaluate the vaccine potential of L. monocytogenes inactivated by gamma irradiation (KLM-γ) encapsulated in alginate microcapsules associated or not with chitosan against listeriosis in the murine model. At the fourth day after challenge there was a reduction in bacterial recovery in mice vaccinated with KLM-γ encapsulated with alginate or alginate-chitosan, with lower bacterial loads in the spleen (10 fold) and liver (100 fold) when compared to non-vaccinated mice. In vitro stimulation of splenocytes from mice vaccinated with alginate-chitosan-encapsulated KLM-γ resulted in lymphocyte proliferation, increase of proportion of memory CD4+ and CD8+ T cell and production of IL-10 and IFN-γ. Interestingly, the group vaccinated with alginate-chitosan-encapsulated KLM-γ had increased survival to lethal infection with lower L. monocytogenes-induced hepatic inflammation and necrosis. Therefore, KLM-γ encapsulation with alginate-chitosan proved to have potential for development of novel and safe inactivated vaccine formulations against listeriosis.

Role of c-di-GMP in improving stress resistance of alginate-chitosan microencapsulated Bacillus subtilis cells in simulated digestive fluids

Probiotics (Bacillus subtilis 04178) were entrapped in alginate-chitosan microcapsules by high-voltage electrostatic process. The encapsulation pattern was established as entrapped low density cells with culture (ELDCwc). The performance of ELDCwc cells was investigated against stress environments of simulated digestive fluids. After incubation in simulated gastric (pH 2.5) and intestinal fluids (4% bile salt) for 2h, the survival rate of ELDCwc cells (18.19% and 27.54%) was significantly higher than that of the free cells (0.0000009% and 0.0005%). The reason why B. subtilis embedded in microcapsules can resist the stress environments was that the mass production of extracellular proteins and polysaccharides prompted B. subtilis to form cell aggregates. The production of extracellular proteins and polysaccharides were regulated by the concentration of c-di-GMP and the expression of ydaJKLMN operon, abbA, sinI, slrA, slrB, abrR and sinR. c-di-GMP is important for the production of extracellular polymer substance to enhance probiotic viability in stress environments.

The effect of improved formulation of chitosan-alginate microcapsules of Bifidobacteria on serum lipid profiles in mice

BackgroundProbiotics have been associated with many beneficial effects in human digestive physiology. The aim of this study was to evaluate the effect of improved formulation of chitosan-alginate microcapsules of Bifidobacterium strains on serum triglycerides, cholesterol, HDL, and LDL in mice. MethodsFive approved probiotic strains of Bifidobacterium were tested for anti-proliferative effect and interleukin-8 induction on HT-29 cell lines. Bifidobacterium strains plus five approved Lactobacillus were encapsulated in chitosan-alginate microcapsules and tested for its survival in simulated gastrointestinal conditions. These microcapsules were administered to 4 groups of mice (including 1. Bif (Bifidobacterium strains), 2. Lac (Lactobacillus strains), 3. Bif-Lac (Bifidobacterium plus Lactobacillus strains) and 4. Control) for 8 days. At eighth day, the blood of mice were taken and serum levels of triglycerides, cholesterol, HDL, and LDL of them were determined. ResultsAll of the Bifidobacterium strains significantly (P < 0.001) reduced secretion of IL-8 in HT-29 cells as well as maximum antiproliferative effects (P < 0.001). In addition, all microcapsules showed impressive survival rate in bile (>%94.1) and gastrointestinal (>%78.28) conditions (P < 0.05). Only Bif-Lac group displayed significantly lower serum cholesterol and LDL levels than control group (P < 0.05). Besides, all groups indicate statistically significant weight loss of mice during the 8 days in comparison with the control group (P < 0.05). ConclusionThe results of this study showed that the microencapsulated probiotics with alginate and chitosan had an effective mean of delivery of viable bacterial cells and non-pharmacological interventions use to reduce serum cholesterol and LDL levels in in-vivo condition.

2289-PUB: Comparison of GalT-KO Porcine Islet Xenograft Survival between Microcapsule against Hypoxia and Microcapsule against Fibrosis in Diabetic Mice Model

Hypoxia and fibrosis are one of the most important obstacles for encapsulated islet transplantation. Previously, we have developed alginate-based microcapsules improving fibrosis (alginate-chitosan) or hypoxia (alginate-perfluorodecalin) and proved their effects. In this study, we compared long-term graft survival of encapsulated islet with microcapsule against fibrosis or hypoxia in diabetic mice model, using 1,3-galactosyltransferase gene-knockout (GalT-KO) pigs. Islets were isolated form GalT-KO pigs and then encapsulated with alginate-chitosan or alginate-perfluorodecalin microcapsule. To magnify graft survival gap between different microcapsules, marginal dose of islets were transplanted into streoptozotocin-induced diabetic mice intraperitoneally. Blood glucose level were measured for a year. Intraperitoneal glucose tolerance test (IPGTT) was performed at 6 and 12 months after transplantation. In the alginate-chitosan group, the blood glucose level of diabetic mice decreased after encapsulated islet transplantation. However, blood glucose level increased again within two months in 3 out of 4 mice. In the alginate-perfluorodecalin group, the blood glucose level of diabetic mice decreased after transplantation and maintained normoglycemia more than 6 months. Although blood glucose level tended to increase 6 months after transplantation, it remained below 300 mg/dL by one year. The area under curve (AUC) of IPGTT was similar between two groups at baseline. At 6 months after transplantation, AUC of IPGTT in alginate-perflourodecalin group lower than AUC of alginate-chitosan group. At one year after transplantation, microcapsules were retrieved. Dithizone stain was positive in most retrieved islet and fibrosis was minimal in both groups. In conclusion, microcapsule against hypoxia showed a longer xenograft survival than microcapsule against fibrosis in diabetic mice. Disclosure E. Lee: None. Y. Yang: None. Y. Cho: None. S. Lee: None. J. Cho: None. K. Yoon: None. Funding Cooperative Research Program for Agriculture Science and Technology Development (PJ01345301); Rural Development Administration, Republic of Korea

Получение микрокапсулированной формы симбиотического комплекса пробиотиков Lactobacillus helveticus с использованием альгината и хитозана

Various technologies for producing different forms of probiotic preparations including Vitaflor have been compared. This preparation was created based on two symbiotic Lactobacillus helveticus strains, D-75 and D-76, with proven effects of syntrophy and synergism. It is produced in the form of freeze-dried lactobacilli biomass. It was shown that the biological activity of Vitaflor in an aggressive environment of the gastrointestinal tract (GET) was reduced to a level that excluded both bacterial colonization and therapeutic effect. Alginate-chitosan microcapsules containing the Vitaflor symbiotic complex protected the microorganisms from the aggressive action of the GET medium and provided their time-controlled release. The emulsion encapsulation turned out to be most effective: the protection of live lactobacilli was 5 orders of magnitude higher than that in the Vitaflor preparation and 3 orders of magnitude higher than with the extrusion method of obtaining microcapsules. The emulsion encapsulation developed for Vitaflor can be applied to other microorganisms; the technique is rather simple, easily scalable and does not require complex equipment. probiotics, Lactobacillus helveticus, microencapsulation technology, natural polysaccharides, alginate, chitosan

Morphological, technological and biopharmaceutical studies of alginate-chitosan microcapsules with vinpocetine

The aim of the investigation is to study morphological, technological and biopharmaceutical properties of alginate-chitosan microcapsules with Vinpocetine. Materials and Methods : Alginate-chitosan microcapsules with different concentrations of sodium alginate (0.5%, 1%, 1.5%, 2%, 2.5% and 3%) and a medium viscosity chitosan solution (0.25-0,5%), as well as microcapsules not treated with a solution of chitosan, were obtained. The surface morphology was studied by methods of atomic-powered microscopy with the use of an NT-MDT Corporation probe scanning microscope (model Solver P47 Pro). To study biopharmaceutical properties of the obtained microcapsules, the "Rotating Basket" apparatus was used. Results : It has been found out that the microcapsules not treated with a chitosan solution, have a smooth, transversely striated surface with large heights and deep cavities. With an increase in the concentration of sodium alginate, the surface becomes smoother, the peaks become larger, higher and wider, the cavities get deeper and more sinuous. The microcapsules treated with a chitosan solution, on the contrary, have a rough surface, low heights and shallow cavities, and with an increase in the concentration of sodium alginate, the surface becomes rougher, the heights are evenly distributed along the microcapsule. The spectrophotometry method was used to determine the efficiency of microencapsulation and the release rate of Vinpocetine from the microcapsules per unit time. When the concentration of a sodium alginate solution is 2.5%, the efficiency of microencapsulation is maximum (86.8%). At this concentration, saturation occurs and with its further increase, the efficiency decreases. The maximum release rate of Vinpocetine from microcapsule samples is observed when the concentration of a sodium alginate solution is 1%: it amounts to 41.17%. Conclusion . The amplitude parameters of the microcapsules surface are different at different concentrations. There is a pattern of alternating signs of asymmetry and excess in the samples with chitosan. With a change in the scale of scanning, the surface characteristics of the microcapsules change. The most distinctive details of the structure are visible at the scale of 2 x 2 pm 2 . At the concentration of sodium alginate of 2.5%, the efficiency of microencapsulation is maximum (86.8%). Studying the effect of the concentration of a sodium alginate solution on the release rate of Vinpocetine from the microcapsule samples has shown that at the concentration of 1%, the release rate is 41.17%, and at the concentration of 2.5% it is 4.5%. These microcapsules can be used in order to produce capsules with modified release.

Biofabrication of microcapsules encapsulating beta-TC-6 cells via scalable device and in-vivo evaluation in type 1 diabetic mice.

Type 1 diabetes mellitus (T1DM) is a disease characterized by lack of pancreatic islet function. Whole tissue transplantation appears to be a viable alternative in the management of T1DM. This study aims at the fabrication and evaluation of alginate-chitosan microcapsules encapsulating insulin-secreting beta-TC-6 cells using an automated spraying nozzle. Uniform spherical microcapsules (250-350 µm) encapsulated with beta-TC-6 cells were fabricated in large quantities in a short span of time. Microencapsulated beta-TC-6 cells were transplanted intraperitoneally into streptozotocin (STZ) induced diabetic mice and monitored for immune tolerance and decrease in blood glucose levels. Mice that received microencapsulated beta-TC-6 cells maintained normoglycemia for 35 ± 5 days before rejection. However, the group that received naked beta-TC-6 cells rejected the cells within 1-2 days, unable to control elevated blood glucose levels. They also exhibited high immune reactions, as evidenced by elevated levels of CD8+ and CD62L T cells. CD4+ T cells that mediated a Th2 response (humoral response) were predominant in microencapsulated beta-TC-6 cells and cells only group as evidenced by elevated levels of CD45R. Our findings from the in-vivo study demonstrated that transplantation of microencapsulated beta-TC-6 cells can be a viable alternative in the management of T1DM with acceptable immune response.

Dissolution Study of Purified Bromelain from Pineapple Cores (Ananas comosus [L.] Merr) Encapsulated in Alginate-Chitosan Microcapsule

Along with the production of large number of pineapple products, the amount of pineapple waste produced is also higher, including pineapple cores with large amount of proteolytic enzyme called bromelain. Bromelain has many benefits, particularly because of its efficacy in various treatments of diseases, such as platelet anti-aggregation, reducing inflammation associated with infections, sinusitis, osteoarthritis and cancer. However, for oral use, bromelain will be degraded by the presence of proteases and the atmosphere of acidic pH in the stomach, so that bromelain will lose its activity. In this study, the isolated and purified bromelain from pineapple cores was subsequently encapsulated in alginate-chitosan microcapsules as drug delivery medium so that bromelain could reach the intestine without degradation in the stomach. The purification using 20%-50% ammonium sulfate obtained bromelain with specific activity of 5.44 U/mg and purity of 2.85 times. The purified enzyme was subsequently dialyzed and yielded of 8.27 U/mg with the purity level of 4.32 times. The dissolution test of bromelain encapsulated in alginate microcapsules resulted in efficiency of 76.99% which dissolute at pH 1.2 as much as 13.53% and at pH 7.4 of 80.09%, while in chitosan-coated alginate microcapsules, efficiency was obtained for 86.40% with dissolution result at pH 1.2 and 7.4 were 8.59% and 77.35% respectively.

Culture of yeast cells immobilized by alginate-chitosan microcapsules in aqueous-organic solvent biphasic system

Immobilization biocatalysis is a potential technology to improve the activity and stability of biocatalysts in nonaqueous systems for efficient industrial production. Alginate-chitosan (AC) microcapsules were prepared as immobilization carriers by emulsification-internal gelation and complexation reaction, and their contribution on facilitating the growth and metabolism of yeast cells were testified successfully in culture medium-solvent biphasic systems. The cell growth in AC microcapsules is superior to that in alginate beads, and the cells in both immobilization carriers maintain much higher activity than free cells, which demonstrates AC microcapsules can confer yeast cells the ability to resist the adverse effect of solvent. Moreover, the performance of AC microcapsules in biphasic systems could be improved by adjusting the formation of outer polyelectrolyte complex (PEC) membrane to promote the cell growth and metabolic ability under the balance of resisting solvent toxicity and permitting substrate diffusion. Therefore, these findings are quite valuable for applying AC microcapsules as novel immobilization carriers to realize the biotransformation of value-added products in aqueous-solvent biphasic systems.