Alginate Microcapsules Research Articles

Bioinspired core-shell microparticle for dual-delivery of prebiotic and probiotic for the treatment of ulcerative colitis

Lactiplantibacillus plantarum (LP) is a well-known probiotic strain that has a beneficial effect in preventing ulcerative colitis. However, delivering a sufficient number of viable LP to the colon still face challenges due to its vulnerability to the highly complex intestinal flora ecosystem. Herein, we present a centrifuge-driven micronozzle system designed for double-layered core-shell alginate microcapsules (DAM), which can serve as an effective carrier for dual delivery of resistant starch nanoparticles (RSNP, prebiotic) and LP (probiotics) for the treatment of colitis. This system enables precise loading of LP and RSNP within the core and shell regions of DAM, respectively. The resulting LP/RS@DAM exhibited a high encapsulation efficiency of LP (108 CFU per bead), in which the dense distribution of RSNP in the shell effectively protected LP against acidic conditions (pH 2) and maintained the cell viability up to 52 % even after long-term storage for 30 days. Furthermore, LP/RS@DAM effectively enhances the production of short-chain fatty acids, leading to a reduction in inflammatory cytokines and restoration of intestinal microbial diversity in dextran sulfate sodium (DSS)-induced colitis. We believe that this innovative approach would offer a potential solution for improving colitis management and paving the way for tailored therapeutic interventions in gastrointestinal disorders.

Optimization and characterization of alginate/cinnamaldehyde electrosprayed microcapsule and its application to mongolian cheese preservation

alginate is a good candidate for encapsulating bioactive compounds because the Na+ on its carboxyl groups can take part in an ion exchange process with Ca2+ to generate a calcium alginate shell. Electrospraying technology was used to prepare cinnamaldehyde (CA)-loaded alginate microcapsules. The generation of microcapsules with a minimal diameter could improve the mass transfer of encapsulated materials. The electrospraying parameters were optimized using response surface methodology (RSM). The results indicated that lower alginate concentration led to microcapsules with smaller diameters. The interaction between the concentration of alginate and the needle size affecting the microcapsule diameter was more significant than other mutual interactions. The optimum conditions were an alginate concentration of 1.27 % (w/v), needle size of 24.62 G, flow rate of 2.29 mL/h, voltage of 12.98 kV, CaCl2 concentration of 0.30 M, and distance of 11.01 cm. With a minimal diameter (155.34 μm), the obtained microcapsules displayed good encapsulation efficiency (86.00 ± 1.7 %) and loading capacity (45.00 ± 2.6 %), which had better preserving effects for Mongolian cheese. The study provided a reference for the production of the microcapsules with high antimicrobial effectiveness, exploring the new technological developments and applications of alginate.

Boric Acid Removal from Water with Alginate Based Beads and Films as Adsorbents

High levels of boron cause harmful effects on humans, animals and plants. While boron is an important auxiliary nutrient for plants, excessive amounts cause toxic effects. The removal of boron in wastewater from chemical processes, industrial processes and agriculture is an important field of study. One of the most widely used methods for boron removal is adsorption method due to its low cost and ease of processing. In this study, adsorption method and sodium alginate microcapsules and sodium alginate-carbon nanotube film adsorbents were used as adsorbents for boric acid removal. In adsorption studies, sodium alginate-carbon nanotube film adsorbents with 42.11% boron removal were more efficient than sodium alginate microcapsules As a result of kinetic studies, it was found that the study was consistent with the pseudo-first order kinetic model.

Co-Encapsulation of Coffee and Coffee By-Product Extracts with Probiotic Kluyveromyces lactis.

Coffee and coffee by-products contain several chemical compounds of great relevance, such as chlorogenic acid (CGA), trigonelline, and caffeine. Furthermore, yeasts have been the target of studies for their use as probiotics because of their interesting biochemical characteristics. The combined administration of probiotic microorganisms with components that provide health benefits mediated by alginate encapsulation is an alternative that ensures the stability of cells and chemical compounds. In this context, the aim of this work was to co-encapsulate the probiotic yeast Kluyveromyces lactis B10 and extracts of green coffee beans, coffee silverskin, and PVA (black, green or immature, and sour coffee beans). The bioactive composition, antioxidant and antimicrobial activities of the extracts, microcapsule morphological characteristics and encapsulation efficiency, ability of the encapsulation to protect the yeast cells subjected to gastrointestinal conditions, and antioxidant activity of the microcapsules were evaluated. All the evaluated extracts showed antioxidant activity, of which PVA showed 75.7% and 77.0%, green coffee bean showed 66.4% and 45.7%, and coffee silverskin showed 67.7% and 37.4% inhibition of DPPH and ABTS•+ radicals, respectively, and antimicrobial activity against the pathogenic bacteria E. coli, Salmonella, and S. aureus, with high activity for the PVA extract. The microcapsules presented diameters of between 1451.46 and 1581.12 μm. The encapsulation efficiencies referring to the yeast retention in the microcapsules were 98.05%, 96.51%, and 96.32% for green coffee bean, coffee silverskin, and PVA, respectively. Scanning electron microscopy (SEM) showed that the microcapsules of the three extracts presented small deformations and irregularities on the surface. The K. lactis cells encapsulated in all treatments with the extracts showed viability higher than 8.59 log CFU/mL, as recommended for probiotic food products. The addition of green coffee bean, coffee silverskin, and PVA extracts did not reduce the encapsulation efficiency of the alginate microcapsules, enabling a safe interaction between the extracts and the K. lactis cells.

ALGINATE-BASED CELL ENCAPSULATION USING DIFFERENT CROSSLINKER ELEMENTS

Alginate microcapsules are the most frequently used materials for cell transplantation. Different crosslinkers affect crosslinking affinity, which has a significant influence on microcapsule properties. The objective was to prepare in vitro microcapsules using calcium, barium, iron, manganese, nickel, and strontium as divalent cations to observe their potential for use in cell transplantation. Sodium alginate was added dropwise to the individually prepared crosslinkers to observe diffusion-based gelling. Alginate microcapsules were investigated regarding capsule stability, physiological properties, and cell viability. After 30 days of incubation, cell viability was greater than 90% for the cell-encapsulated microcapsules when crosslinked with CaCl2 and NiCl2. Viability decreased in the following order: [Formula: see text]. A compression test was performed to investigate the required force to deform 30% of microcapsules, and only MnCl2, FeCl2 (180[Formula: see text]mM), and NiCl2 (50[Formula: see text]mM) demonstrated higher resistance to the applied force than CaCl2. Except for the FeCl2 group, all cell-encapsulated microcapsules remained intact for 45 days. Potential sensitivities to CaCl2 during cell transplantation may compel alternative crosslinker usage, and our study revealed that NiCl2 and BaCl2 can be used as alternative crosslinkers to CaCl2 due to their high cell viability and consistent stability.

Probing of New Polymer-Based Microcapsules for Islet Cell Immunoisolation.

Islet allotransplantation offers a promising cell therapy for type 1 diabetes, but challenges such as limited donor availability and immunosuppression persist. Microencapsulation of islets in polymer-coated alginate microcapsules is a favored strategy for immune protection and maintaining islet viability. This study introduces Poly [2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) as an innovative coating material for microcapsules. PMETAC enhances biocompatibility and durability, marking a significant advancement in islet encapsulation. Our approach combines alginate with PMETAC to create Langerhans islet microcapsules, simplifying material composition and preparation and ultimately lowering costs and increasing clinical applicability. Our comprehensive evaluation of the stability (including osmotic stability, thermal stability, and culture condition stability) and cytotoxicity of a novel microencapsulation system based on alginate-PMETAC-alginate offers insights into its potential application in islet immunoisolation strategies. Microcapsules with PMETAC content ranging from 0.01 to 1% are explored in the current work. The results indicate that the coatings made with 0.4% PMETAC show the most promising outcomes, remaining stable in the mentioned tests and exhibiting the required permeability. It was shown that the islets encapsulated in this manner retain viability and functional activity. Thus, alginate microcapsules coated with 0.4% PMETAC are suitable for further animal trials. While our findings are promising, further studies, including animal testing, will be necessary to evaluate the clinical applicability of our encapsulation method.

Encapsulation of resveratrol in alginate microcapsules using internal gelation technique: Fabrication, characterization and release kinetics

Resveratrol (RES) is a proven anticancer, antioxidant, anti-inflammatory, and cardioprotective compound. However, low bioavailability, poor water solubility, and sensitivity to UV light and heat limit RES's use in food applications. In this study, we aim to protect RES by encapsulating it in sodium alginate (NaAlg) matrix using internal gelation, followed by drying the moist microencapsulates using spray and freeze-drying techniques. The spray-dried microencapsulates exhibited a smaller mean diameter (5.57 ± 2.40 μm), higher encapsulation efficiency (91.32 ± 1.98%), and higher ζ-potential (−61.9 ± 2.33 mV) compared to freeze-dried microencapsulates. SEM images revealed the smooth and spherical surface of the spray-dried microencapsulates, while the freeze-dried samples exhibited irregular shapes and porous textures. FTIR results showed polyelectrolyte interactions between NaAlg, RES, and CaCO3. XRD and DSC results confirmed the incorporation of RES in the NaAlg matrix. Spray-dried microencapsulates demonstrate the highest RES retention of 80.89 ± 0.70% and 78.59 ± 0.27% after 4 h of UV light and thermal treatments, respectively. In vitro release studies showed that spray-dried microencapsulates demonstrate a delayed gastric release compared to freeze-dried microencapsulates. The release mechanism of RES from the microencapsulates was effectively described by the Shalin-Peppas model.

Nanominerals Packaged in pH‐Responsive Alginate Microcapsules Exhibit Selective Delivery in Small Intestine and Enhanced Absorption and Bioavailability

AbstractMineral supplementation is crucial for human nutrition to facilitate appropriate growth, disease prevention, and improved reproductive health. The conventional forms of mineral supplementation involve an ionic form of elements mixed with biomolecules; however, suffer from unfavorable reactions under an acidic environment of stomach, ROS generation, and poor absorption in the small intestine. To address this, nanominerals (NMs) of six essential mineral elements are synthesized and packed in pH‐responsive microcapsule. Each NMs is coated with biomolecules that are known to rapidly absorb through the intestinal epithelium. Microcapsules are found intact at acidic pH (pH: 2.0–6.5); however, selectively release NMs at pH ≥7.0. The in vitro study demonstrates that the mixture of NMs and microcapsules is biocompatible and exhibits excellent ROS scavenging ability at physiological pH. Oral administration of NMs‐loaded microcapsules to rats shows enhanced levels of minerals, vitamin B12, hemoglobin, and total antioxidant activity in blood. The liver, kidneys, and spleen show enhanced expression of Cu/Zn‐SOD and Mn‐SOD enzymes due to high absorption and bioavailability of ZnO, Cu2O, and MnO2 NMs through the intestine. Thus, the pH‐responsive microcapsules hold promise to effectively stealth the encapsulated nutrient materials from the acidic environment of stomach and precisely deliver them to small intestine.

Biocompatible and nondegradable microcapsules using an ethylamine-bridged EGCG dimer for successful therapeutic cell transplantation

Conventional alginate microcapsules are widely used for encapsulating therapeutic cells to reduce the host immune response. However, the exchange of monovalent cations with divalent cations for crosslinking can lead to a sol-gel phase transition, resulting in gradual degradation and swelling of the microcapsules in the body. To address this limitation, we present a biocompatible and nondegradable epigallocatechin-3-gallate (EGCG)-based microencapsulation with ethylamine-bridged EGCG dimers (EGCG(d)), denoted as ‘Epi-Capsules’. These Epi-Capsules showed increased physical properties and Ca2+ chelating resistance compared to conventional alginate microcapsules. Horseradish peroxidase (HRP) treatment is very effective in increasing the stability of Epi-Capsule((+)HRP) due to the crosslinking between EGCG(d) molecules. Interestingly, the Epi-Capsules(oxi) using a pre-oxidized EGCG(d) can support long-term survival (>90 days) of xenotransplanted insulin-secreting islets in diabetic mice in vivo, which is attributed to its structural stability and reactive oxygen species (ROS) scavenging for lower fibrotic activity. Collectively, this EGCG-based microencapsulation can create Ca2+ chelating-resistance and anti-oxidant activity, which could be a promising strategy for cell therapies for diabetes and other diseases.

Immobilization of EPS-modified sodium alginate microcapsule by co-polymerization for methylene blue dye adsorption and kinetics

Exopolysaccharide (EPS) was extracted from Bacillus sp. and purified by ethanol precipitation method. This work mainly examines the dye removal efficiency of biopolymer beads (sodium alginate microcapsules) encapsulated with EPS extracted from Bacillus sp. Encapsulation of EPS-modified sodium alginate microcapsule was done by co-polymerization method. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the co-polymerization of sodium alginate and EPS in the microcapsule. The adsorption capacity of the microcapsule was found to be 0.58682 mg/mL which can be attributed to the larger surface area and increased surface sites in the microcapsule adsorbent. Increased dye removal efficiency of 83% was observed for the microcapsule with 50 mg/mL of EPS. The results of the methylene blue dye adsorption experiment show that the adsorption fitted into the Freundlich isotherm and followed pseudo-second-order reaction with correlation coefficients of 0.939 and 0.9673, respectively. The prepared sodium alginate biopolymer is biodegradable, and numerous studies have documented its biodegradability. Overall, these results evidenced that dye adsorption from textile effluent can be easily managed using the biodegradable polymer materials. Hence, this immobilization approach can be effectively used in textile dye removal process.

Effect of microcapsules’ mechanical stability on the encapsulated cells’ behavior

Stem cell microencapsulation offers immunoprotection, utilizing natural polymers such as sodium alginate (SA), chitosan, and derivatives such as trimethyl chitosan (TMC). Additive minerals improve microcapsule properties and cell differentiation. Layering increases mechanical strength and shields cells from the host’s immune system. This study explores the impact of incorporating nano-hydroxyapatite (nHA) and graphene oxide (GO) into the three-layer alginate–TMC–alginate microcapsules housing human adipose mesenchymal stem cells (haMSCs). The experimental design focused on optimizing the mechanical stability, with the ideal GO and nHA contents identified as 0.81% and 34% w/w, respectively. Rheological analysis revealed enhanced mechanical consistency, evidenced by higher storage modulus and lower loss factor in the optimized sample. Viability of the microencapsulated haMSCs, assessed through acridine orange/propidium iodide staining and MTT assays, affirmed the nontoxic nature of the microcapsules. Osteogenic potential was evaluated via alkaline phosphatase (ALP) activity measurement and immunocytochemistry staining. Microcapsules containing nHA and GO exhibited significantly elevated ALP activity, underscoring the pivotal role of these additives in enhancing mesenchymal stem cell differentiation. The highest osteocalcin deposition occurred in the optimized and SA/nHA 40% w/w groups in the differentiation medium. This comprehensive investigation highlights the potential of three-layer microcapsules with nHA and GO for bone tissue engineering applications.

Controllable hydrophobization of sands with self-healing polymeric microcapsules

Hydrophobized soils have functional hydrophobic coatings to delay or restrict water infiltration and thus prevent infrastructure failure and long-term degradation. Over time, hydrophobized soils will be subjected to degradation under the action of external stresses, leading to the loss of its functional properties. Microencapsulation approaches, initially developed for self-healing applications emerge as a potential solution to enhance, switch (from hydrophilic) or prolong the longevity of hydrophobized soils. The aim of this study is to produce and investigate the effectiveness of microencapsulation to impart hydrophobicity in granular materials in response to external stimuli. In this research, polydimethylsiloxane (PDMS), with hydrophobic properties, is encapsulated in calcium alginate microcapsules with the ionic gelation method. The effectiveness of the microcapsules to induce hydrophobicity is investigated by mixing sand with microcapsules and quantifying the change of the contact angle and water drop penetration time (measures of hydrophobicity) under an external trigger, i.e., under drying and consecutive wetting–drying cycles. The results show that microcapsules release the hydrophobic cargo (PDMS) during shrinkage. After drying, the PDMS content in sand increased to 0.1–0.8% by mass of sand. The released hydrophobic cargo (PDMS) induced hydrophobicity in sands, reflected by a contact angle increase from 29.7° to at least 87.7°. The amount of polydimethylsiloxane encapsulated is a key parameter controlling the release of hydrophobic cargo. In addition, 4% capsule content in sands is identified as an effective microcapsule content in inducing hydrophobicity.

Intestinal delivery of encapsulated bacteriocin peptides in cross-linked alginate microcapsules

Oral delivery of larger bioactive peptides (>20 amino acids) to the small intestine remains a challenge due to their sensitivity to proteolytic degradation and chemical denaturation during gastrointestinal transit. In this study, we investigated the capacity of crosslinked alginate microcapsules (CLAMs) formed by spray drying to protect Plantaricin EF (PlnEF) (C-EF) in gastric conditions and to dissolve and release PlnEF in the small intestine. PlnEF is an unmodified, two-peptide (PlnE: 33 amino acids; PlnF: 34 amino acids) bacteriocin produced by Lactiplantibacillus plantarum with antimicrobial and gut barrier protective properties. After 2 h incubation in simulated gastric fluid (SGF) (pH 1.5), 43.39 % ± 8.27 % intact PlnEF was liberated from the CLAMs encapsulates, as determined by an antimicrobial activity assay. Transfer of the undissolved fraction to simulated intestinal fluid (SIF) (pH 7) for another 2 h incubation resulted in an additional release of 16.13 % ± 4.33 %. No active PlnEF was found during SGF or sequential SIF incubations when pepsin (2,000 U/ml) was added to the SGF. To test PlnEF release in C-EF contained in a food matrix, C-EF was mixed in peanut butter (PB) (0.15 g C-EF in 1.5 g PB). A total of 12.52 % ± 9.09 % active PlnEF was detected after incubation of PB + C-EF in SGF without pepsin, whereas no activity was found when pepsin was included. Transfer of the remaining PB + C-EF fractions to SIF yielded the recovery of 46.67 % ± 13.09 % and 39.42 % ± 11.53 % active PlnEF in the SIF following exposure to SGF and to SGF with pepsin, respectively. Upon accounting for the undissolved fraction after SIF incubation, PlnEF was fully protected in the CLAMs-PB mixture and there was not a significant reduction in active PlnEF when pepsin was present. These results show that CLAMs alone do not guard PlnEF bacteriocin peptides from gastric conditions, however, mixing them in PB protected against proteolysis and improved intestinal release.

The Construction of Sodium Alginate/Carboxymethyl Chitosan Microcapsules as the Physical Barrier to Reduce Corn Starch Digestion.

To enhance the resistant starch (RS) content of corn starch, in this work, carboxymethyl chitosan/corn starch/sodium alginate microcapsules (CMCS/CS/SA) with varying concentrations of SA in a citric acid (CA) solution were designed. As the SA concentration increased from 0.5% to 2%, the swelling of the CMCS/CS/SA microcapsule decreased from 15.28 ± 0.21 g/g to 3.76 ± 0.66 g/g at 95 °C. Comparatively, the onset, peak, and conclusion temperatures (To, Tp, and Tc) of CMCS/CS/SA microcapsules were higher than those of unencapsulated CS, indicating that the dense network structure of microcapsules reduced the contact area between starch granules and water, thereby improving thermal stability. With increasing SA concentration, the intact and dense network of CMCS/CS/SA microcapsules remained less damaged after 120 min of digestion, suggesting that the microcapsules with a high SA concentration provided better protection to starch, thereby reducing amylase digestibility. Moreover, as the SA concentration increased from 0.5% to 2%, the RS content of the microcapsules during in vitro digestion rose from 42.37 ± 0.07% to 57.65 ± 0.45%, attributed to the blocking effect of the microcapsule shell on amylase activity. This study offers innovative insights and strategies to develop functional starch with glycemic control properties, holding significant scientific and practical value in preventing diseases associated with abnormal glucose metabolism.

Effect of Agavins and Agave Syrup Use in the Formulation of a Synbiotic Gelatin Gummy with Microcapsules of Saccharomyces Boulardii.

Agavins are reserve carbohydrates found in agave plants; they present texture-modifying properties and prebiotic capacity by increasing the viability of the intestinal microbiota. Through its hydrolysis, agave syrup (AS) can be obtained and can be used as a sweetener in food matrices. The objective of this work was to evaluate the effect of the variation in the content of agavins and AS on the physical, structural, and viability properties of Saccharomyces boulardii encapsulates incorporated into gelatin gummies. An RSM was used to obtain an optimized formulation of gelatin gummies. The properties of the gel in the gummy were characterized by a texture profile analysis and Aw. The humidity and sugar content were determined. A sucrose gummy was used as a control for the variable ranges. Alginate microcapsules containing S. boulardii were added to the optimized gummy formulation to obtain a synbiotic gummy. The viability of S. boulardii and changes in the structure of the alginate gel of the microcapsules in the synbiotic gummy were evaluated for 24 days by image digital analysis (IDA). The agavins and agave syrup significantly affected the texture properties (<1 N) and the Aw (>0.85). The IDA showed a change in the gel network and an increase in viability by confocal microscopy from day 18. The number of pores in the gel increased, but their size decreased with an increase in the number of S. boulardii cells. Agavins and cells alter the structure of capsules in gummies without affecting their viability.

Enhanced self-healing of micro-cracks in concrete using graphene oxide encapsulated sodium alginate microcapsules: microstructure, elemental, and oxide composition analysis

Enhanced self-healing of micro-cracks in concrete using graphene oxide encapsulated sodium alginate microcapsules: microstructure, elemental, and oxide composition analysis

Preparation and evaluation of microcapsules of sodium alginate based on microfluidic technology

Many active ingredients in food products are destroyed by gastric acids and enzymes as they pass through the stomach, thereby reducing the desired effect of the target ingredient. In addition, traditional microcapsule preparation methods usually break up the dispersion by mechanical stirring or oscillation, which generates droplets of uneven size and inconsistent inclusion content, and mechanical external forces may cause denaturation and inactivation of active substances. This study aimed to use microfluidics to generate Oil-in-water-in-oil (O/W/O) droplet structures with good monodispersity and highly tunable properties, and to further prepare microcapsules with high encapsulation rate and targeted intestinal release by taking advantage of the cross-linking properties of alginate that reacts with Ca2+ under acidic conditions. Finally, the particle size distribution, release effect, encapsulation effect and oxidative stability of the core-shell microcapsules were evaluated. In this study, two types of microcapsules, homogeneous and core-shell microcapsules, were prepared by selecting tea polyphenols and vitamin E as models for hydrophilic and lipophilic bioactive compounds, respectively. Thin shell microcapsules with a shell thickness of about 25 μm were prepared using PDMS chip conditioning. Large microcapsules with a particle size of 230 μm were generated by using capillary glass tube chips, which had an excellent antioxidant property with a retention rate of 88.66 ± 1.25% of VE after 20 days of storage at 4 °C, while all of the VE was oxidized in the bare environment. In addition, in simulated gastric fluid, the release of VE was only about 20%, while in artificial intestinal fluid, the release was close to 100%, so the microcapsules also had intestinal targeting properties.

Technological Functionalisation of Microencapsulated Genistein and Daidzein Delivery Systems Soluble in the Stomach and Intestines.

Encapsulating antioxidant-rich plant extracts, such as those found in red clover, within microcapsules helps protect them from degradation, thus improving stability, shelf life, and effectiveness. This study aimed to develop a microencapsulation delivery system using chitosan and alginate for microcapsules that dissolve in both the stomach and intestines, with the use of natural and synthetic emulsifiers. The microcapsules were formed using the extrusion method and employing alginate or chitosan as shell-forming material. In this study, all selected emulsifiers formed Pickering (β-CD) and traditional (white mustard extract, polysorbate 80) stable emulsions. Alginate-based emulsions resulted in microemulsions, while chitosan-based emulsions formed macroemulsions, distinguishable by oil droplet size. Although chitosan formulations with higher red clover extract (C1) concentrations showed potential, they exhibited slightly reduced firmness compared to other formulations (C2). Additionally, both alginate and chitosan formulations containing β-CD released bioactive compounds more effectively. The combined use of alginate and chitosan microcapsules in a single pill offers an innovative way to ensure dual solubility in both stomach and intestinal environments, increasing versatility for biomedical and pharmaceutical applications.

Loading Levi Lactobacillus brevis into chitosan-coated alginate microcapsules and their effect on the testicular tissue redox system in roosters of hen's broiler breeders

Microencapsulation protects lactic acid bacteria against adverse conditions of environment and gastrointestinal tract and increases their survival. This study was conducted with three treatments, namely control, alginate-L. brevis (AL-LAB), and alginate-chitosan-L. brevis (AL-CHI-LAB). The results showed that the zeta-potential for microcapsules fixed by AL-CHI–LAB and AL–LAB were -16.5 and -17.2 mV, respectively. The SEM images showed cubic and non-aggregated structures for three types of microcapsules. The significantly highest survival rate for the AL-CHI-LAB observed in the GIT simulated conditions (59/50 %), and the significantly highest survival rate for the AL-LAB at the in vivo conditions of the GIT (50 %). To investigate SOD and GPX gene expression levels in roosters' testicular tissues, L. brevis was fed (106 CFU/g) to thirty-two roosters aged about 60 weeks for two months. The GPX gene expression level in the testicular tissue was higher in the AL-CHI-LAB (6.57) than other treatments and it was not significantly different from the AL-LAB (4.09). The SOD gene expression was not significantly different among treatments. The results indicated that AL-CHI-LAB could improve the antioxidant capacity of testicular tissues by increasing the GPX gene expression, thereby improving aging-related reproductive performance.

A novel, microfluidic high-throughput single-cell encapsulation of human bone marrow mesenchymal stromal cells

The efficacy of stem-cell therapy depends on the ability of the transplanted cells to escape early immunological reactions and to be retained at the site of transplantation. The use of tissue engineering scaffolds or injectable biomaterials as carriers has been proposed, but they still present limitations linked to a reliable manufacturing process, surgical practice and clinical outcomes. Alginate microbeads are potential candidates for the encapsulation of mesenchymal stromal cells with the aim of providing a delivery carrier suitable for minimally-invasive and scaffold-free transplantation, tissue-adhesive properties and protection from the immune response. However, the formation of stable microbeads relies on the cross-linking of alginate with divalent calcium ions at concentrations that are toxic for the cells, making control over the beads’ size and a single-cell encapsulation unreliable. The present work demonstrates the efficiency of an innovative, high throughput, and reproducible microfluidic system to produce single-cell, calcium-free alginate coatings of human mesenchymal stromal cells. Among the various conditions tested, visible light and confocal microscopy following staining of the cell nuclei by DAPI showed that the microfluidic system yielded an optimal single-cell encapsulation of 2000 cells/min in 2% w/v alginate microcapsules of reproducible morphology and an average size of 28.2 ± 3.7 µm. The adhesive properties of the alginate microcapsules, the viability of the encapsulated cells and their ability to escape the alginate microcapsule were demonstrated by the relatively rapid adherence of the beads onto tissue culture plastic and the cells’ ability to gradually disrupt the microcapsule shell after 24 h and proliferate. To mimic the early inflammatory response upon transplantation, the encapsulated cells were exposed to proliferating macrophages at different cell seeding densities for up to 2 days and the protection effect of the microcapsule on the cells assessed by time-lapse microscopy showing a shielding effect for up to 48 h. This work underscores the potential of microfluidic systems to precisely encapsulate cells by good manufacturing practice standards while favouring cell retention on substrates, viability and proliferation upon transplantation.Graphical