Nowadays, phage therapy emerges as one of the alternative solutions to the problems arising from antibiotic resistance in pathogenic bacteria. Although phage therapy has been successfully applied both in vitro and in vivo, one of the biggest concerns in this regard is the stability of phages in body environment. Within the scope of this study, microencapsulation technology was used to increase the resistance of phages to physiological conditions, and the resulting microcapsules were tested in environments simulating body conditions. For this purpose, Bacillus subtilis, Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis), and Salmonella enterica subsp. enterica serovar Typhimurium (Salmonella Typhimurium) phages were isolated from different sources and then microencapsulated with 1.33% (w/v) sodium alginate using a spray dryer to minimize the damage of physiological environment. Stability of microcapsules in simulated gastric fluid and bile salt presence was tested. As a consequence, the maximum titer decrease of microencapsulated phages after 2-h incubation was found to be 2.29 log unit for B. subtilis phages, 1.71 log unit for S. Enteritidis phages, and 0.60 log unit for S. Typhimurium phages, while free phages lost their viability even after a 15-min incubation. Similarly, microencapsulation was found to increase the stability of phages in the bile salt medium and it was seen that after 3 h of incubation, the difference between the titers of microencapsulated phages and free phages could reach up to 3 log unit.
- MeSH
- Alginates MeSH
- Bacteria classification virology MeSH
- Bacteriophages drug effects isolation & purification physiology MeSH
- Cell Encapsulation * MeSH
- Microbial Viability MeSH
- Drug Stability MeSH
- Gastric Juice MeSH
- Bile Acids and Salts pharmacology MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Alginates MeSH
- Bile Acids and Salts MeSH
This paper deals with the treatment of hazardous zinc-bearing waste using hydraulic binders and silicone polymers, with the aim to allow its safe disposal into landfill. The waste was solidified using hydraulic binders in the first step and then encapsulated using silicone polymers. Samples were characterised using x-ray fluorescence, x-ray diffraction, and scanning electron microscopy. The effectiveness of the process was evaluated by leaching tests in distilled water and in an acidic environment according to Toxicity Characteristic Leaching Procedure. The effect of porosity and pH on the release of pollutants was also studied. Zinc and chloride were identified as the most significant pollutants in the waste. Portland cement did not stabilize them efficiently. The two-step treatment with Portland cement and silicone binders decreased, in the best case, the concentration of zinc and chloride in acidic extracts from 12,400 mg/L and 38,300 mg/L to 21.9 mg/L and 74 mg/L, respectively, and the treated waste complied with regulatory requirements for hazardous waste disposal into landfills. The two-step treatment was also found as a more effective method than microencapsulation using a silicone binder alone. The factor that most affects leachability appears to be the porosity of the encapsulated waste.
- Keywords
- Leaching tests, Metal plating wastes, Silicone polymers, Stabilisation/solidification, Zinc,
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Biological biocides have the potential to reduce plant biotic stresses and boost development, but they tend to be unstable and degrade quickly. BCAs inhibit plant diseases and enhance crop productivity while being eco-friendly. Encapsulation research has increased in recent decades in response to the growing need for BCAs. These formulations can address the difficulties of free-form formulations. They can improve the efficacy of BCAs by prolonging their shelf life and offering the controlled release of biological components. Using a novel approach, they can be a potential platform for controlling biotic stressors, especially plant pathogens. Chitosan and alginate are two important biopolymers with great potential in enclosing BCAs. These can also be used alone for encapsulation, but their application in composite form eliminates the disadvantages of using them alone. However, several other biopolymers have significant roles in formulating BCAs, such as gums, gelatin, starch, and pectin. Given the amazing potential of these new formulations, this comprehensive review highlights more recent developments about encapsulating BCAs based on nano and micro-materials and their appliances in reducing plant biotic stressors. These prospects might provide the foundation for future opportunities to expand the efficacy and application BCAs by formulation technologies to combat plant pathogens.
- Keywords
- Biological control, Biopolymers, Biotic stresses, Encapsulation, Nanomaterials,
- MeSH
- Alginates MeSH
- Biopolymers pharmacology MeSH
- Chitosan * pharmacology MeSH
- Stress, Physiological MeSH
- Plants MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
- Names of Substances
- Alginates MeSH
- Biopolymers MeSH
- Chitosan * MeSH
The aim of this study was optimization of spray-drying process conditions for microencapsulation of Turkish oregano extract. Different concentrations of maltodextrin and gum arabic as encapsulating agents (wall material) as well as influence of selected processing variables were evaluated. The optimal conditions were maintained on the basis of the load of main bioactive compounds - ursolic, rosmarinic acids and carvacrol - in prepared microparticles after comparison of all significant response variables using desirability function. Physicomechanical properties of powders such as flowability, wettability, solubility, moisture content as well as product yield, encapsulation efficiency (EE), density, morphology and size distribution of prepared microparticles have been determined. The results demonstrated that the optimal conditions for spray-drying mixture consisted of two parts of wall material solution and one part of ethanolic oregano extract when the feed flow rate was 40 mL/min and air inlet temperature -170 °C. Optimal concentration of wall materials in solution was 20% while the ratio of maltodextrin and gum arabic was 8.74:1.26.
- Keywords
- Gum arabic, maltodextrin, microencapsulation, origanum onites, plant extract,
- MeSH
- Gum Arabic MeSH
- Origanum * MeSH
- Drug Compounding * MeSH
- Capsules MeSH
- Desiccation MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Gum Arabic MeSH
- Capsules MeSH
The purpose of this study was to improve the survival of Bifidobacterium animalis subsp. lactis 10140 during freeze-drying process by microencapsulation, using a special pediatric prebiotics mixture (galactooligosaccharides and fructooligosaccharides). Probiotic microorganisms were encapsulated with a coat combination of prebiotics-calcium-alginate prior to freeze-drying. Both encapsulated and free cells were then freeze-dried in their optimized combinations of skim milk and prebiotics. Response surface methodology (RSM) was used to produce a coating combination as well as drying medium with the highest cell viability during freeze-drying. The optimum encapsulation composition was found to be 2.1 % Na-alginate, 2.9 % prebiotic, and 21.7 % glycerol. Maximum survival predicted by the model was 81.2 %. No significant (p > 0.05) difference between the predicted and experimental values verified the adequacy of final reduced models. The protection ability of encapsulation was then examined over 120 days of storage at 4 and 25 °C and exposure to a sequential model of infantile GIT conditions including both gastric conditions (pH 3.0 and 4.0, 90 min, 37 °C) and intestinal conditions (pH 7.5, 5 h, 37 °C). Significantly improved cell viability showed that microencapsulation of B. lactis 10140 with the prebiotics was successful in producing a stable symbiotic powdery nutraceutical.
- MeSH
- Bifidobacterium physiology radiation effects MeSH
- Time Factors MeSH
- Gastrointestinal Tract microbiology MeSH
- Infant MeSH
- Humans MeSH
- Freeze Drying * MeSH
- Microbial Viability radiation effects MeSH
- Infant Formula MeSH
- Colony Count, Microbial MeSH
- Drug Compounding MeSH
- Probiotics radiation effects MeSH
- Drug Storage methods MeSH
- Temperature MeSH
- Check Tag
- Infant MeSH
- Humans MeSH
- Publication type
- Journal Article MeSH
Light microscopy has been used for the evaluation of the internal and external structure of dry microcapsules. The method involves surface and penetrative staining with various dyes after which the microcapsules were embedded in suitable optically translucent material. Using this method the core material, its shape and position within the microcapsules either in total or as subunits of the core are clearly distinguishable from the wall material. The surface characteristics of the microcapsules can be observed with either light or fluorescent microscopy after staining with a fluorescent dye. Furthermore, it is a relatively simple and inexpensive method by comparison with the scanning electron microscopy. The natural character of microcapsules, without any artificial structures, has been maintained. It could serve as a routine auxiliary method for complex evaluation or control of the microencapsulation process and its optimization.
- MeSH
- Staining and Labeling MeSH
- Emulsions MeSH
- Microscopy * MeSH
- Drug Compounding MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Emulsions MeSH
Microencapsulation of a carbon nanotube (CNT)-loaded paraffin phase change material, PCM in a poly(melamine-formaldehyde) shell, and the respective CNT-PCM gypsum composites is explored. Although a very low level (0.001-0.1 wt %) of intramicrocapsule loading of CNT dopant does not change the thermal conductivity of the solid, it increases the measured effusivity and thermal buffering performance during phase transition. The observed effusivity of 0.05 wt % CNT-doped PCM reaches 4000 W s-0.5 m-2 K-1, which is higher than the reported effusivity of alumina and alumina bricks and an order of magnitude larger than the solid, CNT-free PCM powder. The CNT dopant (0.015 wt %) in a 30 wt % PCM-plaster composite improved the effusivity by 60% compared to the CNT-free composite, whereas the addition of the same amount of CNTs to the bulk of the plaster does not improve either the effusivity or the thermal buffering performance of the composite. The thermal enhancement is ascribed to a CNT network formation within the paraffin core.
- Keywords
- CNT, energy storage, microencapsulation, phase change materials (PCM), thermal buffering, transient plane source method,
- Publication type
- Journal Article MeSH
Probiotic bacteria are widely used in pharmaceutics to offer health benefits. Microencapsulation is used to deliver probiotics into the human body. Capsules in the stomach have to keep bacteria constrained until release occurs in the intestine. Once outside, bacteria must maintain enough motility to reach the intestine walls. Here, we develop a platform based on two label-free optical modules for rapidly screening and ranking probiotic candidates in the laboratory. Bio-speckle dynamics assay tests the microencapsulation effectiveness by simulating the gastrointestinal transit. Then, a digital holographic microscope 3D-tracks their motility profiles at a single element level to rank the strains.
- Publication type
- Journal Article MeSH
Recently, a growing number of plant essential oils (EOs) have been tested against a wide range of arthropod pests with promising results. EOs showed high effectiveness, multiple mechanisms of action, low toxicity on non-target vertebrates and potential for the use of byproducts as reducing and stabilizing agents for the synthesis of nanopesticides. However, the number of commercial biopesticides based on EOs remains low. We analyze the main strengths and weaknesses arising from the use of EO-based biopesticides. Key challenges for future research include: (i) development of efficient stabilization processes (e.g., microencapsulation); (ii) simplification of the complex and costly biopesticide authorization requirements; and (iii) optimization of plant growing conditions and extraction processes leading to EOs of homogeneous chemical composition.
- Keywords
- botanical pesticides, microencapsulation, nanosynthesis, natural product research, stabilization processes,
- MeSH
- Biological Control Agents metabolism MeSH
- Biological Products metabolism MeSH
- Oils, Volatile metabolism MeSH
- Plant Oils metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
- Names of Substances
- Biological Control Agents MeSH
- Biological Products MeSH
- Oils, Volatile MeSH
- Plant Oils MeSH
- MeSH
- Models, Biological MeSH
- Cells * MeSH
- Kidney Failure, Chronic therapy MeSH
- Hemoperfusion MeSH
- Humans MeSH
- Membranes, Artificial * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Membranes, Artificial * MeSH
