Release Of Core Material Research Articles

The in-vitro digestion behaviors of milk proteins acting as wall materials in spray-dried microparticles: Effects on the release of loaded blueberry anthocyanins

Studies have shown that microencapsulation can protect blueberry anthocyanins (ACNs) from degradation. Naturally derived micellar casein and whey protein isolate (WPI) are commonly employed as wall materials owing to their unique digestion properties, which are believed to significantly influence the stability and release of core materials in the gastrointestinal tract. Micellar casein and WPI were used to prepare spray-dried microparticles to load ACNs. The dynamic release of ACNs was investigated during in vitro digestion from the perspective of structural changes in wall materials, which were mainly identified by scanning electron microscopy and confocal laser scanning microscopy. ACN-loaded micellar casein microparticles dissolved slowly and coagulated into oversized curds during digestion, which significantly improved the retention of ACNs in the harsh gastrointestinal tract. In contrast, ACN-loaded WPI microparticles dissolved quickly, but liquid microparticles subsequently formed and hindered the release and degradation of ACNs. This study provides a reference for the design of spray-dried microparticles and should help in understanding the release behaviors of loaded bioactive compounds in other delivery systems containing such proteins during in vitro digestion.

Preparation of Microcapsules Coating and the Study of Their Bionic Anti-Fouling Performance.

With the increasing demands to better the marine environment, environmentally friendly anti-fouling coatings have attracted attention from society. Adding hydrolyzable microcapsules without toxin to paints is a very useful and safe method to get bionic anti-fouling coatings with a micro-nano surface structure. Based on this trend, a form of environment-friendly microcapsules were prepared through mini-emulsion polymerization. The target microcapsules had a poly(urea-formaldehyde) (PUF) shell and a mixed core of silicone oil and capsaicin. Additionally, the microcapsules were introduced into zinc acrylate resin to obtain bionic anti-fouling coatings with micro-nano morphology. The effects of polyvinyl alcohol (PVA) molecular weight, stirring rate, and temperature on the morphology of the microcapsules were studied by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that spherical nanoparticles with smooth surfaces were obtained, and the mean diameter was approximately 1.38 μm when the molecular weight of PVA was 77 K, the stirring rate was 600 rpm and the temperature was 55 °C. Fourier-transform infrared spectra (FTIR) results showed that the silicone oil and capsaicin were successfully encapsulated, the core materials of the microcapsules reached 72.37% and the yield of microcapsules was 68.91% by the Soxhlet method. Furthermore, the hydrophobicity, corrosion resistance and anti-fouling performance of the coatings were evaluated by the water contact angle, electrochemical and real-sea tests. The results indicated that the anti-fouling coatings had excellent hydrophobicity and anti-fouling performance due to the micro-nano convex structure and the release of core materials. Encouragingly, the anti-fouling coatings show excellent and long-term anti-fouling performance, which is expected to be widely applied in marine anti-fouling coatings.

Feasibility study on corrosion protection of steel bar in a self-immunity system based on increasing OH− content

In this paper, a kind of novel ethyl cellulose (EC)/calcium hydroxide microcapsule to establish a self-immunity system based on increasing hydroxyl content for the reinforced concrete is proposed. The capacity for lifting the threshold value of [Cl−]/[OH−] in this system is feasibly evaluated. Different dosages of microcapsules are placed in the sodium chloride solution with a concentration of 3.5wt% to characterize the corrosion protection by means of linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The working mechanism of this system consists of the chemical triggering (capsule shell) and releasing (capsule core) processes when a microcapsule is exposed a decreasing pH condition, and the release of core materials in turn restores the alkaline environment against steel bar depassivation. The test results of environmental scanning electron microscopy (ESEM) equipped with texture element analysis microscopy (TEAM) reveal that the capsule shell sensible to the [Cl−]/[OH−] ratio forms an excellent low-pH trigger mechanism. In addition, the electrochemical experiment indicates the chloride-induced corrosion intensity of a steel bar can be monitored with the decreasing Icorr and more negative Ecorr, which is further observed by the pitting characteristics of steel bars.

SHELL MATERIAL'S PERFORMANCE OF THE MICROCAPSULE FOR ELECTROLYTIC CO-DEPOSITION

The shell material of microcapsules has an important effect on the electrolytic co-deposition behavior, the release of core material and the surface performance of composite coating. This paper discussed the tensile property and the stability of three shell materials including polyvinyl alcohol (PVA), gelatin and methyl cellulose (MC). It is found that these three shell materials have good mechanical strength and flexibility which are favorable to electrolytic co-deposition and stability of microcapsules in composite coating and that MC has well permeability and porosity which has a positive effect on the release of the core material in composite coating. Moreover, the study of the thermal properties and water vapor permeability of the three shell materials showed that their permeability improved with increase of temperature and humidity. In addition, the composite copper coating containing microcapsules with PVA, gelatin or MC as shell material was prepared respectively.

Composite tectocapsules via the self-assembly of functionalized poly(divinylbenzene) microspheres

Abstract Poly(divinylbenzene-55)[poly(DVB-55] microspheres were used as building blocks to form polymer capsule walls consisting of interconnected microspheres. The microspheres had to be surface-functionalized with maleic acid to facilitate their interfacial assembly. In addition, porous and functionalized poly(DVB-55) microspheres were embedded across interfacial polyurea capsule membranes to form composite tectocapsules where release of core materials is designed to occur through the microsphere pores, rather than by conventional wall diffusion. Electron microscopy and X-ray spectromicroscopy were used to characterize the wall compositions, and release data are presented to illustrate the role of microspheres acting as release portals.

Effect of ethylcellulose grade and sealant treatments on the production and in vitro release of microencapsulated sodium salicylate.

Sodium salicylate was microencapsulated with ethylcellulose 100 cp by polymer deposition from cyclohexane by temperature change to give a finer product, with slower drug release, than that obtained with 10 cp grade of ethylcellulose. Scanning electron microscope and polymer disc swelling studies confirmed that larger microcapsules after drug release ruptured into smaller particles with swollen surfaces containing pores. Treatment of microcapsules with paraffin wax solution retarded release of core material, the release being affected by the percentage of sealant used and the particle size of the product. The mechanism of release from the sealed microcapsules was complex involving mainly diffusion, but polymer erosion and drug binding were also involved. Other sealant materials were less effective in retarding dissolution.

Structure and development of viruses as observed in the electron microscope. XI. Entry and uncoating of herpes simplex virus.

Two morphologically distinct types of capsids are described. The dense capsid appeared to be disrupted near the cellular membrane with release of core material. The light capsid was more stable and was frequently encountered close to the nucleus, where empty capsids were also found. Pretreatment of cells before infection with either puromycin or actinomycin D markedly decreased the percentage of empty capsids. It is suggested that the two types of capsids play different roles in the process of initiating infection. One (the dense capsid) releases deoxyribonucleic acid (DNA) shortly after entry. This DNA is transcribed into a virus-specific ribonucleic acid, which codes for an enzyme capable of altering the permeability of the second type of capsid (the light capsid). In proximity to the nucleus, the infectious DNA then escapes without gross disruption of the capsid.