Particle Size Of Microcapsules Research Articles

Preparation and characterization of Sparassis latifolia β-glucan microcapsules

Abstract In order to effectively protect the biological activity of Sparassis latifolia β-glucan, improve its stability, and realize its high-value utilization, single-factor test and orthogonal test were carried out to optimize the microencapsulation conditions of S. latifolia β-glucan prepared using spray drying method. The β-glucan microcapsules were characterized by scanning electron microscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and laser particle size analyzer. The results showed that the optimal microencapsulation conditions were as follows: maltodextrin and whey protein with a mass ratio of 1:2, core and wall material with a mass ratio of 1:2, and monoglyceride and core material with a mass percentage of 0.3. Under these conditions, the powder yield and embedding rate of β-glucan microcapsules were 47.32 ± 0.58% and 86.76 ± 1.19%, respectively. The preparation technique was proved to be stable. The β-glucan microcapsules were spherical particles, with the characteristics of a smooth surface, no cracks. The particle size of microcapsules was smaller, and its Dv (50) was 8.43 µm. The distribution of microcapsules was more uniform, and its uniformity was 0.503. The good embedding performance and high thermal stability can effectively protect the biological activity of the core material.

Microencapsulated Lactobacillus acidophilus FNCC 0051 and Streptococcus thermophilus FNCC 0040 Technique Emulsion Using Gelatin and Sodium Alginate

The research was held from September 2021 until January 2022 in Laboratory Livestock Product Technology Universitas Brawijaya, Malang, Indonesia. Microencapsulation is a technique used to protect bacteria from harmful (extreme) environmental factors such as heating, freezing and low pH through a coating process or coating a core substance in this case LAB with a polymer wall layer. The purpose of this study was to obtain a combination of the use of gelatin and sodium alginate as a coating material in the encapsulation of Lactobacillus acidophilus FNCC 0051 and Streptococcus thermophilus FNCC 0040 using the emulsion technique based on its physical and microbiological properties. The research method used is a laboratory experiment using a completely randomized design (CRD) pattern with 3 treatments and 3 replications. The treatment using a combination of gelatin and sodium alginate consisted of T1 (1:1); T2 (1:2); T3 (1:3). Data were processed by Analysis of Variance (ANOVA); If the analysis happens to show a significant difference (P<0.05) or a very highly significant difference (P<0.01), then the Duncan's Multiple Range Test was applied. Data from the results of microstructure testing using Scanning Electron Microscopy which were qualitative were analyzed descriptively. The results of the analysis show that encapsulation using a combination of gelatin and sodium alginate gives a very significant difference (P<0.01) to the value of encapsulation efficiency and does not give a significant difference (P>0.05) on microcapsule particle size and microcapsule particle size distribution, with percentages T1 97.43±0.31%, T2 98.50±0.48%, T3 99.00±0.44 %; T1 1.08±0.07 µm; T2 1.18±0.11 µm; T3 0.95±0.11µm; and T1 4.79±1.04; T2 2.53±2.16; T3 4.15±3.13 and microcapsules using SEM showed the microcapsules were round and smooth. The combination of gelatin and sodium alginate T3 (1:3) as a microcapsule material is a good alternative to protect lactic acid bacteria so that it can be applied in food products functional.

Synthesis and characterization of layered double hydroxides hybrid microcapsules for anticorrosion via self-healing and chloride ion adsorption

Self-healing and corrosion resistance microcapsule (S/CMC) was fabricated by solvent evaporation method with tung oil (TO) as core, layered double hydroxides (LDH) as corrosion inhibitor and ethyl cellulose (EC) as wall. The average particle size of microcapsule increased with the increase of LDH content when LDH was less than 20 wt%. LDH component was present in the wall of S/CMC by surface loading, the chlorine adsorption performance of microcapsule in neutral environment was superior to that in alkaline environment. LDH was hybridized in EC to form stable wall structure. The LDH embedded in hybrid wall captured chloride ion by surface adsorption and ion exchange to improve the corrosion resistance of steel bar. This study provides a solution for the compatibility of anti-corrosion and self-healing technology, and provides a new perspective for the anti-corrosion application of microcapsule.

Extraction kinetic model of polysaccharide from Codonopsis pilosula and the application of polysaccharide in wound healing

The crude polysaccharide (CPNP) of Codonopsis pilosula was obtained by hot-water extraction technology. The extraction kinetic model established according to Fick’s first law of diffusion and related parameters of polysaccharide was studied. CPNP microcapsules were prepared by blending with sodium alginate, Ca2+ ions and crude CPNP. The quality control (drug loading rate, embedding rate and release rate, etc) of CPNP microcapsules were analyzed by pharmacopeas standards. The structure feature of CPNP microcapsules also were determined with various methods. The wound healing ability of CPNP microcapsules loading with different concentration of CPNP was evaluated using the rat wound model. The activity of various enzymes and the expression levels of pro-inflammatory factors in the model skin tissue also were determined by enzyme linked immunosorbent assay (ELISA). Hematoxylin-eosin staining (HE), Masson, immunohistochemistry were used to investigate the external application effect of CPNP microcapsules on skin wound repair. The extraction kinetics of CPNP was established with the linear correlation coefficient (R2) of 0.83–0.93, implied that the extraction process was fitted well with the Fick’s first law of diffusion. The CPNP has good compatibility with sodium alginate and Ca2+ ions by SEM and TEM observation, and the particle size of CPNP microcapsules was 21.25 ± 2.84 μm with the good degradation rate, loading rate (61.59%) and encapsulation rate (55.99%), maximum swelling rate (397.380 ± 25.321%). Compared with control group, the redness, and swelling, bleeding, infection, and exudate of the damaged skin decreased significantly after CPNP microcapsules treatment, and the CPNP microcapsules groups exhibited good wound healing function with less inflammatory cell infiltration. The pathological structure showed that in the CPNP microcapsules group, more newborn capillaries, complete skin structure, and relatively tight and orderly arrangement of collagen fibers were observed in the skin of rats. CPNP microcapsules could effectively inhibit the high expression of pro-inflammatory factors in damaged skin, and significantly increase the contents of related enzymes (GSH-Px, T-AOC, LPO) and collagen fibers. The relative expression levels of genes (VEGF and miRNA21) in the CPNP microcapsules group were higher than those in the model group and the negative group. The above results suggested that the CPNP microcapsules could controlled-release the CPNP to the wound surface, and then played a better role in antibacterial, anti-inflammatory and skin wound repair.

Preparation and characterization of damage indication and self‐healing microcapsules for surface micro‐cracks in mortar coating

AbstractA mortar coating with damage indication and self‐healing properties based on microcapsules was proposed. The self‐healing microcapsules were synthesized by in‐situ polymerization method using urea formaldehyde resin as wall material and epoxy resin as core material. The damage‐indicator microcapsules with leuco dye crystal violet lactone as core material and polymethyl methacrylate as wall material were fabricated by solvent evaporation method. It was confirmed that after the core material was encapsulated, the heat resistance was improved. Through the particle diameter analysis of the microcapsules fabricated at diverse emulsifier contents and stirring speeds, it can be found that the microcapsule particle size decreased with increasing the emulsifier content and stirring speed. When cracks on the surface of the mortar coating were artificially fabricated, the damage‐indicator microcapsules can effectively highlight the surface cracks in blue for further manual repairs. The cured epoxy resin was found through the scanning electron microscope observation and element detection of the crack section. This indicated that the self‐healing microcapsules can fill micro‐cracks, thereby slowing down the development speed of cement‐based material cracks. This study provides a new method to detect and self‐heal surface micro‐cracks in mortar coating.

Preparation and property optimization of bistable electrochromic microcapsules

In the improvement of stability and lifetime of bistable electrochromic (EC) materials, the microcapsule technique was used to protect the EC materials in a polymer shell, which was named bistable EC microcapsules (BEC-Ms). However, the particle size and shell thickness of microcapsules will affect their properties, such as response time, coloration efficiency, and bistable property. In this study, BEC-Ms was prepared via solvent evaporation method filled with PMMA as the shell and the mixture of crystal violet lactone (CVL), tetrabutylammonium perchlorate (TBAP), and phase change material (PCM) as the core. The particle size and shell thickness of microcapsules were adjusted and systematically investigated by controlling the emulsification rate and mass ratio of polymer shell to core. The optimized BEC-Ms with 2 μm size and 22.94 nm thickness showed excellent performance including fast response time (about 1 s), far lower than the safety of human body drive voltage (2 V), coloration efficiency (932 cm2 C−1), and good bistability (216 h). This approach provides a viable and alternative to flexible energy-efficient wearable display-related devices and smart textiles.

High efficiency microencapsulation of extra virgin olive oil (EVOO) with novel carrier agents: Fruit proteins

Coating materials are incorporated into microencapsulation systems for improving stability against environmental stress and functionality (such as hydrophilic features) of sensitive food products (core materials) having desirable nutrition profiles. Assuming that the final powder products containing these materials in a high proportion (at least 50%) will be offered for consumption, it is essential to include coating materials with health beneficial effects in these systems to reach exactly the desired objectives. Therefore, many studies are interested in reducing the applications of carbohydrates used commonly in microencapsulation techniques. In this context, proteins, especially plant-based alternatives obtained from food processing by-products draw attention. Similarly, the current study focused on the utilization of sour cherry protein isolate (SCPI) and pomegranate protein isolate (POPI) as novel (innovative) coating materials in the microencapsulation of extra virgin olive oil (EVOO). The EVOO was also loaded into commercial proteins including pea protein isolate (PPI) and gelatin protein isolate (GPI). The spray dryer air inlet temperature for microencapsulation step of prepared emulsions (the ratio of EVOO to protein, 1:1) was 160 °C. Microencapsulation efficiency (MEE) was 97.71%, 90.27%, 89.55%, and 88.15% for sour cherry protein microcapsules (SCPM), pomegranate protein microcapsules (POPM), pea protein microcapsules (PPM), and gelatin protein microcapsules (GPM), respectively. On the other hand, POPI loaded with EVOO showed superior microencapsulation yield (MY) (60.50%) compared to PPIM (48.50), SCPIM (42.35%), and GPIM (33.30%). The impact of proteins on the morphology and particle size of microcapsules was also established. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and x-ray diffraction (XRD) analyses were conducted to confirm the presence of EVOO in the protein matrix. Thermogravimetric analysis (TGA) results showed that the maximum decomposition temperature of all samples was between 200 and 500 °C but mass loses rates differed in these temperatures. SCPI and POPI were required for providing higher thermal stability to EVOO rather than commercial proteins. Novel plant-based proteins and commercial proteins loaded with EVOO showed similar limitations against the oil oxidation and no significant increase in the peroxide value of encapsulated EVOO at 60 °C during 7 days of storage were noted. The results support such fruit proteins for commercial production to use in microencapsulation applications as coating materials.

Co-encapsulation of L-ascorbic acid and quercetin by gelatin/sodium carboxymethyl cellulose coacervates using different interlayer oils

A two-step emulsification prior to complex coacervation was employed to develop a co-encapsulation technology of hydrophilic and hydrophobic components for nutrition enhancement. Processing parameters of mononuclear ellipse-like microcapsules using gelatin and sodium carboxymethyl cellulose as wall materials were evaluated. The particle size and morphology of microcapsules and the encapsulation efficiency of L-ascorbic acid were significantly affected by the water–oil phase ratio and total biopolymer concentration. The L-ascorbic acid and quercetin co-encapsulated microcapsules with an average size of 65.26 µm showed good physical and chemical stability. The encapsulation efficiencies of L-ascorbic acid and quercetin were 69.91% and 88.21%, respectively. To predict the potential of functional lipids as hydrophobic carriers, microcapsules using soybean oil, olive oil, fish oil, and conjugated linoleic acid as interlayer oils were developed. The encapsulation efficiencies of hydrophobic compounds carried by different oils were similarly high (88.21–93.08%), whereas, hydrophilic ones carried by conjugated linoleic acid had the lowest encapsulation efficiency (32.54%). The interface tension results indicated that the interfacial stability was impaired by a competitive relation between conjugated linoleic acid and hydrophobic emulsifier at the interface, due to their structural similarity. These results provided the guidance for improving the quality of interlayer oils from microcapsules.

Early Age Strength Healing Effect of Cementitious Composite Incorporated Self-Healing Microcapsule

Received 27 February 2019; accepted 02 September 2019
 This paper aims to explore early age strength healing effect of cementitious composite incorporated self-healing microcapsule and curing activity of self-healing microcapsule. Particle characteristic of the microcapsule and micromorphology of cement paste incorporated the microcapsule were characterized by SEM. Curing activity of the microcapsule was analyzed by macroscopic solidification test, DSC and TGA. The influence factors of early age strength healing ratio in cementitious composite incorporated self-healing microcapsule were studied. The results showed that epoxy resin microcapsule had favorable micromorphology. Epoxy resin microcapsule core material had good curing activity and possessed the ability to play the healing role in cementitious composite. Healing temperature and healing age had less impact on the healing effect of the microcapsule in cementitious composite. The microcapsule could be kept good shape in cement paste and combined with cement paste closely. The microcapsule also could rupture and had better dispersion in cement paste. The main fracture behavior of the microcapsule was based on small hole ruptured when cement paste did not occur macro damage. When pre-loading was 0.75 σmax, the particle size of microcapsules was range from 75 μm to 150 μm, proportion of epoxy curing agent was 20 % and proportion of the microcapsule was 6 %, early age strength healing ratio reached the highest of 24.1 %.

Preparation and Properties of a Novel Sodium Alginate Microcapsule

In this study, sodium alginate was used as the main embedding material, and sodium polyacrylate had been immobilized on sodium alginate with calcium ions as crosslinking agent for preparing a new type of lactic acid bacteria entrapment material. The aim of this study was to investigate the viability of Lactococcus lactis NCU1315 under simulated gastrointestinal conditions and the physical properties of the microcapsules and their protective effects on Lactobacillusto develop a feasible and stable method for preparing microbial particles. The hardness of Alg-1 and Alg-2 microcapsules varied with time in simulated gastric juice and showed significant difference at the second and third hour (P < 0.05, P < 0.01). The particle size of Alg-1 and Alg-2 microcapsules varied with time in simulated gastric juice and showed significant difference at the second and third hour (P < 0.05, P < 0.01). Alg-1 had no significant effect on the growth of NCU1315, but Alg-2 had inhibitory effect on the growth of Lactococcus lactis NCU1315. The survival rate of Lactococcus lactis in Alg-1 and Alg-2 microencapsulated groups was significantly higher than that in Free cell group at 24h, 48h and 72h (P < 0.05, P < 0.01). However, the survival rate of Lactococcus lactis in Alg-1 and Alg-2 microencapsulated groups decreased with time (P<0.05, P<0.01).

Development of double layer microcapsules for enhancing the viability of Lactobacillus casei LC2W in simulated gastrointestinal fluids

In this study, Lactobacillus casei LC2W (LC2W) was encapsulated by double layer microcapsules that were prepared by adjusting the amount of sodium alginate and whey protein (1:0, 1:1, 1:1.5, and 1:2, namely AWC-1, AWC-2, AWC-3, and AWC-4, w/w). Cellulose nanocrystals (CNCs) coating was applied as an outer layer by complex coacervation. The effect of temperature and storage time on the viability of encapsulated LC2W was determined, and their survival was evaluated after exposure to simulated gastric fluid (SGF, pH 2.5) and simulated intestinal fluid (SIF, pH 7.4). The results indicated that the particle size of dry microcapsules was 0.45–0.57 mm with an encapsulation efficiency (EE) of 83.25%–84.34%. The viability of LC2W encapsulated in AWC-3 at optimal conditions reached 6.72 and 5.97 log CFU/g at 4 °C and 25 °C, respectively, after 120 days of storage, whereas it reduced when the temperature was increased from 30 °C to 60 °C. The survival of encapsulated LC2W in AWC-3 in SGF was higher than that in SIF, and the cell counts were 6.56 and 5.96 log CFU/g, respectively. This study demonstrated that the prepared microcapsules could enhance LC2W viability in the intestine, indicating a great application potential in functional foods and milk-based products.

The Development, Evaluation, and Antioxidant Activity Analysis of Chitosan Microcapsules Containing Red Ginger Oleoresin with Sodium Tripolyphosphate Prepared by Emulsion Cross-linking Technique

In this study, chitosan-based carrier of red ginger oleoresin was prepared using the emulsion cross-linking technique with sodium tripolyphosphate (TPP) as a cross-linking agent. The effect of chitosan and TPP concentration, as well as pH on the encapsulation efficiency, particle size and characterization of chitosan microcapsule was determined. The antioxidant activity of microcapsules was analyzed. Chitosan microcapsules containing red ginger oleoresin were produced although with non-smooth surfaces.

Evaluation of fat substitute mimicking Chinese human milk by its physicochemical properties and oxidative stability

To develop nutritional oil similar to Chinese human milk in terms of fatty acids composition and triglyceride, several vegetable oils and 1,3-dioleoyl-2-palmitoylglycerol (OPO) were selected to prepare nutritional oil microcapsule. The result showed that human milk fat substitute (HMFS) prepared by these oils (soybean oil (SO): camellia oil (CMO): high oleic sunflower oil (HOSO): corn oil (CRO): OPO = 28.24:0.00:12.94:8.82:50.00) was the optimal formula. After spray drying, the final microcapsule product was milky white with good solubility and microencapsulation efficiency (MEE = 92.1%). The dispersion coefficient of the microcapsule particle size distribution was 0.200 and the average particle size was 202.767 nm, both particle size distribution experiment and scanning electron microscope (SEM) analysis indicated that the particle size of the microcapsule was uniform and the surface was smooth, After 30 days’ accelerated experiment, the peroxide value of microcapsule products was 10.24 meq/kg, indicating the product had good oxidative stability. Practical applications Human milk is considered the most ideal food source for newborns, but not all cases have human milk for infant. Therefore, it is necessary to produce formula milk powder whose composition and function are closer to human milk. This study used five commonly edible oils and added OPO to develop a HMFS similar to human milk in fatty acids and triglycerides. The optimal formula contributed to long shelf life (27 months) and good physicochemical properties, promoting the development of HMFS.

Preparation, Optimization and Release Behaviour Evaluation of Carbamide Peroxide Microcapsules Integrated with Eudragit RS

AbstractSlow‐release microcapsules were prepared by solvent evaporation method under different conditions with carbamide peroxide (CP) and Eudragit RS (EuRS) as core material and shell material respectively. Encapsulation efficiency (EE), release control, particle size and particle surface were characterized by UV spectrophotometer, light microscope, laser diffraction analysis (LDA) and scanning electron microscope (SEM). The results showed that CP microcapsules possessed a relatively regular spherical morphology. The particle size of microcapsules was generally distributed between 150∼500 μm. CP was in EuRS microcapsules in crystal phase. And magnesium stearate (MS) was used as stabilizer agent in emulsion, and it would also prolong the release time. The optimum condition of preparation was under 20°C, stirring rate was slightly higher than 400 rpm, and to obtain better release control, the optimal ratio of CP/EuRS was 1/3, MS proportion was 9.3 g/100 mL, and MS particle size was smaller than 32 μm. The maximum %EE was 94.59 %, the longest release duration was about 180 min, and the longest available storage of CP microcapsules was about 20 days under refrigeration. The release behavior of CP microcapsules can be explained by First‐order‐kinetic model.

Microencapsulation of sea buckthorn (Hippophae rhamnoides L.) pulp oil by spray drying.

The aim of this work was to encapsulate sea buckthorn (Hippophae rhamnoides L.) pulp oil (SBPO) by spray drying. Gum Arabic (GA) and maltodextrins (MD) were used as wall materials. The effects of several factors, including GA to MD ratio, total solids content of emulsion, wall to core ratio, and inlet air temperature, on the microencapsulation efficiency (ME) were investigated. The optimization of operation conditions was realized by response surface methodology (RSM). The optimal conditions were as follows: GA to MD ratio 2.38, total solids content 39%, wall to core ratio 5.33, and inlet air temperature 154°C. Under the optimal conditions, the ME of SBPO microcapsules was 94.96 ± 1.42%. The physicochemical properties of microcapsules were also invested. SBPO microcapsules obtained had low water activity, low moisture content, high water solubility, and high bulk density. For the morphological characteristics, cracks and pores were not observed in most microcapsules, which was beneficial for the protection of ingredients in microcapsules. The particle size of SBPO microcapsules ranged from 0.01 to 5 μm, and the mean diameter d 4,3 was 2.55 μm. The analysis results of fourier transform infrared spectroscopy (FTIR) informed the presence of SBPO in microcapsules. There were no significant differences in the content of the main fatty acids in SBPO before and after spray drying. The results of oxidative stability showed that the microencapsulation by spray drying could effectively protect SBPO from oxidation and extend the shelf life of SBPO.

Structural regulation of poly(urea-formaldehyde) microcapsules containing lube base oil and their thermal properties

Regulating the micro-structure of microcapsules containing lubricant is paramount to their properties and the subsequent self-lubrication performance of the composites. In this study, poly(urea-formaldehyde) (PUF) microcapsules containing lube base oil as lubricant have been fabricated by in-situ polymerization technology. The structure and properties of PUF microcapsules are investigated by altering the emulsifier content, homogenization time, oil viscosity and synthetic method. The content of sodium lignosulfonate, an environment-friendly emulsifier, has important regulation effect on the regularity and core content of PUF microcapsules. The homogenization time and oil viscosity directly affect the particle size and distribution of PUF microcapsules. Moreover, the oil viscosity plays an important role in regulating the morphology and thermal behavior of PUF microcapsules. Specifically, by adding low content of emulsifier (0.2 wt %), well-dispersed spherical microcapsules are obtained. Adopting 15# oil as core material and 0.2 wt % emulsifier, high core content of up to 89.2 wt % is achieved. When using lube base oil (32#, 46# oil) with high viscosity, the microcapsules show compact spherical structure and high thermal stability, with the initial decomposition temperature of up to 251.8 °C. This research can provide guidance for fabricating PUF microcapsules with suitable structures and performances for improving the tribological properties of different polymers.

Preparation and Optimization of Waterborne Acrylic Core Microcapsules for Waterborne Wood Coatings and Comparison with Epoxy Resin Core.

Microcapsules were prepared by in situ polymerization with urea formaldehyde resin as the wall material and Dulux waterborne acrylic acid as the core material. The effects of the core–wall ratio, water bath temperature and depositing time on the morphology, particle size, yield and encapsulation ratio of microcapsules were investigated by orthogonal experiment of three factors and two levels. The results showed that the core–wall ratio had the greatest influence on the performance of microcapsules. When the core–wall ratio was 0.58:1, the water bath temperature was 70 °C, and the depositing time was 5 d, the microcapsule performance was the best. With the increase in depositing time, the yield of microcapsule particles increased gradually, and the microcapsules appeared to show an adhesive phenomenon. However, the long-term depositing time did not lead to complete deposition and agglomeration of microcapsules. When 10.0% concentration of the waterborne acrylic microcapsules with 0.58:1 of core–wall ratio was added to the coatings, the mechanical and optical properties of the coatings did not decrease significantly, but the elongation at break increased significantly. Therefore, this study offers a new prospect for using waterborne acrylic microcapsules to improve the toughness of waterborne paint film which can be cured at room temperature on a wood surface.

Optimisation of spray drying parameters for Lactobacillus acidophilus encapsulation in whey and gum Arabic: Its application in yoghurt

To maintain viable cells over the critical value of 106 cfu g−1 throughout shelf life of probiotic yoghurt, Lactobacillus acidophilus LA-5 was encapsulated by spray drying using whey powder (WP) and gum arabic (GA) mixtures. Box-Behnken Design (BBD) method was used to optimise drying conditions and WP to GA ratio in wall material. Responses were recorded for encapsulation efficiency and production efficiency of microcapsules. Optimum conditions were determined as: inlet air temperature, 140 °C; liquid flow rate, 0.485 L h−1; WP to GA ration 0.83:0.17 (dry weight basis), resulting in 93.95% maximum encapsulation efficiency and 48.36% maximum production efficiency. After exposure to simulated gastrointestinal conditions, the microcapsules produced under optimum conditions provided better protection of L. acidophilus, when compared with free cells, with a reduction of 10.84% and 24.54%, respectively. Particle size of microcapsules was D50:6.276 μm, which is acceptable for incorporation into dairy and other food products.

Environmental friendly carrier material for nifedipine as hypertension drug

Nifedipine is a hypertension drug must be consumed three times a day due to its low oral bioavailability. One way of developing a controlled drug delivery system is making nifedipine microcapsules by using environmentally friendly polymers of polylactic acid and polycaprolactone via the evaporation method using oil-in-water solvents. Polylactic acid and polycaprolactone can be said to be environmentally friendly polymers, because they can be degraded naturally in nature both in the biotic, and abiotic environment, or microorganism. In this study, polylactic acid, Polycaprolactone, and nifedipine were dissolved in dichloromethane solvent; then, an emulsifier was added for the emulsification stage. After passing through the dispersion stage for the process of compaction of the microcapsules by solvent evaporation, the microcapsules were filtered. Microcapsules were characterized using particle size analysis, X-ray diffractometry, and scanning electron microscopy, respectively. The drug release percentage was determined by dissolving microcapsules for 55 hours using a buffer at the potential of hydrogen 1.2 and pH 7.4 as dissolution media. In this study, all variations in the composition of polyblend resulted in a percent efficiency of encapsulation ranging from 78.82%-89.84%, and percent release ranging from 6.80%-39.07%. The composition of 100% polylactic acid produces the highest percent encapsulation efficiency of 89.84% but produces the lowest percentage of drug release at 6.80%. The best composition obtained was polylactic acid: polycaprolactone 1:9 (weight per weight), with a percent release of 39.07% and percent encapsulation of 78.82%. Microcapsule solids produced are approximately 96%. Particle Size of microcapsule ranges at 0.5 μM.

Double-Layered Microcapsules Significantly Improve the Long-Term Effectiveness of Essential Oil.

In order to improve the long-term effectiveness of essential oil, a double-layered microcapsule was prepared using the inclusion encapsulation method in this study, with β-cyclodextrin as its inner layer and chitosan and sodium alginate as its outer layer. The optimized preparation process was obtained through the response surface method. The morphology, particle size, encapsulation efficiency, thermal stability and sustained release effect of the double-layered microcapsules were characterized. The microcapsules were spherical, with a particle size distribution between 2–6 μm, and had good thermal stability within 250 °C. Their encapsulation efficiency can be up to 80%, and it can continuously release the active ingredients of the essential oil under normal temperature and high temperature conditions for a long time. In order to further examine the application effect of the double-layered microcapsule, it was loaded onto the cotton fabric by the soak-roll method. The finished cotton fabric showed excellent washability and rubbing fastness. They can still maintain a light fragrance naturally for two months. The microcapsules prepared in this study can be potentially applied in sleep aid, antibacterial, mosquito prevention, food science and other related products.