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Polyether-ether-ketone (PEEK) exhibits great potential in being a replacement for metal components across various applications relying on the mechanical and tribological properties. However, there is still much to be done to improve its properties. The main motivation of this paper is to improve the tribological and mechanical properties of PEEK simultaneously for more severe working environment. Therefore, dialkyl pentasulfide (RC2540) was proposed to fill into the cavity of CNTs to prepare nano-capsules, which were then filled into PEEK to prepare PEEK/nano-capsules composites. The existence of nano-capsules in PEEK was analyzed, and the friction and wear properties exhibited by PEEK composites against GCr15 steel were examined using pin-disk friction pairs, and the self-lubricating mechanism of PEEK composites in friction was revealed. Findings of this study indicated that when the mass fraction of nano-capsules was less than 5%, the filling of nano-capsules could improve the tensile strength of PEEK and reduced the friction coefficient and specific wear rate of PEEK by filling nano-capsules. During the friction process, RC2540 in the nano-capsules can be released as PEEK wears so that a self-lubricating layer can be formed for reducing PEEK composites' friction and wear. [ABSTRACT FROM AUTHOR]

Grinding fluid often struggles to enter the grinding area and overcoming this challenge has been a major focus of research in recent years. Therefore, CNTs@T304 nano-capsules are prepared by filling the cavities of CNTs with a lubricant of T304. CNTs@T304 nano-capsules were used as an additive in this paper to prepare resin grinding wheels and nanofluids, respectively. The resin wheels filled with nano-capsules were used for grinding under the lubrication of nanofluids, and T304 could then be released to the grinding area to play a self-lubricating role during grinding. First, CNTs@T304 nano-capsules were characterized, and the properties of the prepared grinding wheels and nanofluids were tested. Second, the effects of the filling of nano-capsules and grinding speed on the grinding force, grinding temperature, surface roughness, and grinding ratio were studied. Finally, the lubrication mechanism of the nano-capsules was revealed through surface analysis of the workpiece. The results suggested that nano-capsules had good thermal stability and the nanofluid prepared from them exhibited good dispersion stability and thermal conductivity. The grinding wheel was found to satisfy the service conditions when the filling content was less than 15%. Compared with a common wheel, the grinding force and grinding temperature were reduced by 24% and 28%, respectively, and the surface roughness of the workpiece and the grinding ratio were increased by 18% and by 21%, respectively, when grinding GCr15 steel with the nano-capsule wheel. Lubrication with nanofluids could further reduce the grinding force, grinding temperature, and surface roughness values. During grinding, the self-lubrication film formed by the T304 released from the nano-capsules in the wheel served first and foremost as a lubricant. The intervention of the nanofluid enhanced the heat-exchange effect and lubrication efficiency in the grinding zone. [ABSTRACT FROM AUTHOR]

Polyether-ether-ketone (PEEK) exhibits great potential in being a replacement for metal components across various applications relying on the mechanical and tribological properties. However, there is still much to be done to improve its properties. The main motivation of this paper is to improve the tribological and mechanical properties of PEEK simultaneously for more severe working environment. Therefore, dialkyl pentasulfide (RC2540) was proposed to fill into the cavity of CNTs to prepare nano-capsules, which were then filled into PEEK to prepare PEEK/nano-capsules composites. The existence of nano-capsules in PEEK was analyzed, and the friction and wear properties exhibited by PEEK composites against GCr15 steel were examined using pin-disk friction pairs, and the self-lubricating mechanism of PEEK composites in friction was revealed. Findings of this study indicated that when the mass fraction of nano-capsules was less than 5%, the filling of nano-capsules could improve the tensile strength of PEEK and reduced the friction coefficient and specific wear rate of PEEK by filling nano-capsules. During the friction process, RC2540 in the nano-capsules can be released as PEEK wears so that a self-lubricating layer can be formed for reducing PEEK composites’ friction and wear.

Grinding fluid often struggles to enter the grinding area and overcoming this challenge has been a major focus of research in recent years. Therefore, CNTs@T304 nano-capsules are prepared by filling the cavities of CNTs with a lubricant of T304. CNTs@T304 nano-capsules were used as an additive in this paper to prepare resin grinding wheels and nanofluids, respectively. The resin wheels filled with nano-capsules were used for grinding under the lubrication of nanofluids, and T304 could then be released to the grinding area to play a self-lubricating role during grinding. First, CNTs@T304 nano-capsules were characterized, and the properties of the prepared grinding wheels and nanofluids were tested. Second, the effects of the filling of nano-capsules and grinding speed on the grinding force, grinding temperature, surface roughness, and grinding ratio were studied. Finally, the lubrication mechanism of the nano-capsules was revealed through surface analysis of the workpiece. The results suggested that nano-capsules had good thermal stability and the nanofluid prepared from them exhibited good dispersion stability and thermal conductivity. The grinding wheel was found to satisfy the service conditions when the filling content was less than 15%. Compared with a common wheel, the grinding force and grinding temperature were reduced by 24% and 28%, respectively, and the surface roughness of the workpiece and the grinding ratio were increased by 18% and by 21%, respectively, when grinding GCr15 steel with the nano-capsule wheel. Lubrication with nanofluids could further reduce the grinding force, grinding temperature, and surface roughness values. During grinding, the self-lubrication film formed by the T304 released from the nano-capsules in the wheel served first and foremost as a lubricant. The intervention of the nanofluid enhanced the heat-exchange effect and lubrication efficiency in the grinding zone.

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The objective of this work was to analyze the morphological and physicochemical properties of bean starch and its use in nanoencapsulation by spray drying. Starch purity was 81.21 ± 1.43% db with a resistant starch content higher than a commercial corn starch, but with a high protein content and a low amylose content. Starch granules presented smooth surfaces, polyhedral shape and sizes from ~ 1 to 6.3 µm. Black bean starch exhibited an A-type X-ray diffraction pattern with a crystallinity highest than corn starch. Black bean starch showed higher thermal stability than a commercial corn starch. At 90 °C, solubility was 31.0% and swelling power was 31.2 g g−1. The black bean starch gel showed a high stability under refrigeration and freeze–thaw. Small particles and viscosity profile suggested the potential application of black bean starch as wall material during nano spray drying. Black bean starch tends to form spherical aggregates during nano spray drying due to the protein content. Capsules size was in the range of 1.0–2.5 µm, however were observed agglomerated particles by SEM. The encapsulation efficiency of l-ascorbic acid was 36.88 ± 0.55%. The results indicate that black bean starch possesses properties with potential applications in food industries. [ABSTRACT FROM AUTHOR]

Poly(N‐isopropylacrylamide) (PNIPAM) having lower critical solution temperature (LCST) behavior in aqueous solutions has been actively studied for various applications in nanotechnology and controlled drug delivery. In this work, a comb‐coil block copolymer is synthesized with PNIPAM coil and polyethyleneimine brushes. Self‐organization of the copolymer into micelle by heating and subsequent cross‐linking of the part of PEI corona resulted in a unique nanocapsule (i‐CLM) with hydrophilic cross‐linked PEI outer shell and thermo‐responsive PNIPAM inner brush. The nanocapsule appears as a vesicle‐like hollow at room temperature but did into micelle‐like spheres when heated. From dynamic light scattering measurement, it is revealed apparently that the nanocapsule exhibited well the swelling and the shrinking reversibly under heating and cooling and the feature is cycled repeatedly with gradual fashion under wide‐range of temperature responding. The carrier property of the nanocapsule is investigated by using hydrophobic fluorophore of Nile red (NR) as a probe and it is found that the hollow of the nanocapsule is a good nano pocket to promote the growth of nanocrystals of NR. [ABSTRACT FROM AUTHOR]

The design of an encapsulation system consisting of a synthetic peptide which is fully biodegradable into non-toxic constituents. This system should be capable of encapsulating perfluorinated hydrocarbons and should be a promising basis for oxygen carriers to be used as artificial blood replacement. A diblock-peptide is synthesised following a phosgene-free method and characterised by 1H-NMR. Subsequently, this diblock-peptide is self-assembled with perfluorodecalin (PFD) to form PFD-filled capsules as potential artificial oxygen carriers allowing for rapid oxygen uptake and release. The diblock-peptide Bu-PAsp10-PPhe10 is successfully synthesised and used to encapsulate PFD. The capsules have a spherical shape with an average diameter of 360 nm in stable aqueous dispersion. NMR measurements prove their physical capability for reversible uptake and release of oxygen. The resulting capsules are expected to be fully biodegradable and possibly could act as oxygen carriers for artificial blood replacement. [ABSTRACT FROM AUTHOR]

The aim of this study was to optimize the nanoencapsulation of fish Omega 3 fatty acids with use of complex coasevation technique which was performed by using response surface methodology (RSM) in the central composite design (CCD). Nanoparticles containing omega-3 fatty acid were produced by Rainbow trout skin gelatin and Arabic gum as walls using complex coacervation technique. The effects of three independent variables as fish gelatin concentration (33-66%), the concentration of omega-3 fatty acids (10-30%) and the homogenizer speed at three levels (10000, 15000 and 20000 rpm) on the dependent variables such as particle size, oil level, encapsulated oil and nanoencapsulation efficiency were evaluated. The results showed that the homogenizer speed significantly had the greatest impact on the particle size (P

Abstract Background: Ferula assa-foetida is one of the common medicines that was used as antiseptic with a view to traditional uses, it can be used as a safe and effective drug to treat diseases particularly resistant bacterial infections. This study aims to product gelatin nano- capsules containing Ferula assa-foetida essential oil and investigate their antioxidant and antibacterial activities. Materials and Methods: This experimental study was performed on gelatin nano-capsules containing Ferula assa-foetida essential oil (FAO) (2, 4, 6 and 8% w/w), glycerol (25% w/w) as plasticizer and glutaraldehyde as cross-linker. The morphology, antioxidant and antibacterial activities and operation of the nano-capsules were assessed according to American Standards by Scanning Electron Microscopy, ABTS, and microbiological tests. Results: Gelatin nano-capsules exhibited low antioxidant and antibacterial activities while gelatin nano-capsules incorporated with FAO exhibited excellent antioxidant and antibacterial. The highest rates of these effects were seen merged with 8% of FAO. Conclusion: Gelatin nano-capsules merged with FAO have excellent physical form, as well as they are an appropriate antioxidant and antibacterial that have been considered to produce antoxidant and antibacterial drugs.

Objective: The main purpose of the current study was to determine the effect of nano-capsules containing risedronate on calvarial bone formation in rabbit. Materials and Methods: Fifteen adult rabbits were allocated to the study. Four holes were created in the calvarial bone. Holes 1-4 were filled as described below: hole 1 was right unfilled and kept as control; hole 2 was filled with nano bone; hole 3 was filled using an autogenous bone; and hole 4 was filled with a mixture of nano-capsules containing risedronate. At 4, 8 and 12 weeks after surgery, blood samples were obtained and red blood cell, white blood cell, hemoglobin, hematocrit, mean cell volume, mean cell HGB and platelet counts were determined. Then animals were scarified and bone density was determined using radiography images. Results: Bone formation in nano risedronate + autograft and autograft were 0.31 ± 0.03 and 0.25 ± 0.02, respectively, while in nano risedronate and control groups were 0.11 ± 0.01 and 0.08 ± 0.02, respectively (P < 0.05). Significant differences were observed in bone density in nano risedronate + autograft as 0.37 ± 0.01, while the density in the autograft, nano risedronate, and control groups were as 0.32 ± 0.01, 0.14 ± 0.01, and 0.09 ± 0.02, respectively (P < 0.05). Bone density after 12 weeks were 0.51 ± 0.01, 0.36 ± 0.02, 0.21±0.01, and 0.19 ± 0.02 in nano risedronate + autograft, nano risedronate, autograft, and control groups, respectively (P < 0.05). In all stages of the study, the nano risedronate + autograft group had better bone formation in comparison to the other groups (P < 0.05). Different filling materials of defects had no effect on blood hematology indexes (P > 0.05). Conclusion: These results suggest nano risedronate + autograft has positive effects on calvarial bone defects healing in rabbit. [ABSTRACT FROM AUTHOR]

Ionic liquids can serve as an environmentally-friendly replacement for solvents in emulsions, therefore they are considered suitable to be used as an emulsified medium for various active materials one of which are extractors of metal ions. Increasing the extraction efficiency is considered to be one of the key objectives when working with such extraction systems. One way to improve the extraction efficiency is to increase the contact area between the extractant and the working ionic solution. This can be accomplished by creating a nano-emulsion of ionic liquid containing such an extractant. Since emulsification of ionic liquid is not always possible in the sample itself, there is a necessity of creating a stable emulsion that can be added externally and on demand to samples from which metal ions need to be extracted. We propose a method of fabrication of a highly-stable extractant-loaded ionic liquid-in-water nano-emulsion via a low-energy phase reversal emulsification followed by continuous layer-by-layer polyelectrolyte deposition process to encapsulate the nano-emulsion and enhance the emulsion stability. Such a multilayered stabilized nano-emulsion was tested for extraction of Cd 2+ and Ca 2+ ions in order to determine its extraction efficiency and selectivity. It was found to be effective in the extraction of Cd 2+ ions with near 100% cadmium removal, as well as being selective since no Ca 2+ ions were extracted. The encapsulated emulsion was removed from samples post-extraction using two methods – filtration and magnetic separation, both of which were shown to be viable under different circumstances – larger and mechanically stronger capsules could be removed by filtration, however magnetic separation worked better for both smaller and bigger capsules. The long-term stability of nano-emulsion was also tested being a very important characteristic for its proposed use: it was found to be highly stable after four months of storage time. [ABSTRACT FROM AUTHOR]

In the present work, carotenoids were isolated (1.2%) from crude palm oil and encapsulated with isabgol fiber (Psyllium husk). The efficiency of encapsulation was 82.23±1.42%. The morphology of the capsules showed rough surface texture with minimal pores. The amorphous natures of the nano-capsules was obvious from X-ray diffraction patterns. DSC studies showed high thermal stability of the nano-capsules between 20–120 °C. In vitro release studies revealed that controlled release from the nano-capsules could be achieved using isabgol fiber as encapsulant. However it was observed that the nano-capsules followed a non-Fickian diffusion pattern. Good DPPH-radical scavenging and metal-chelation activities were observed for encapsulated carotenoids. Shelf-life studies showed that the nano-capsules gradually degraded at 97% relative humidity, as the moisture-induced rancidity was evidently not extensive.

Objective: Cotton functionalisation with poly-ɛ-caprolactone (PCL) micro- and nano-capsules containing menthol was carried out with the aim of introducing a long-lasting refreshing sensation.Materials and methods: The preparation of the polymer micro- and nano-capsules was carried out by solvent displacement technique. A confined impinging jets mixer was used in order to ensure fast mixing and generate a homogeneous environment where PCL and menthol can self-assemble.Results: The micro- and nano-capsules and the functionalised fabrics were characterised by means of DSC, FT-IR spectroscopy and SEM imaging. Micro- and nano-capsules of different size, from about 200 to about 1200 nm, were obtained varying menthol to PCL ratio (from 0.76 to 8), overall concentration and flow rate (i.e. mixing conditions). The inclusion of menthol was confirmed by DSC analysis.Discussion and conclusion: A patch test was carried out by 10 volunteers. Micro-capsules were found to be effective in conferring the fabric a refreshing sensation without altering skin physiology. [ABSTRACT FROM PUBLISHER]

In the present work, carotenoids were isolated (1.2%) from crude palm oil and encapsulated with isabgol fiber (Psyllium husk). The efficiency of encapsulation was 82.23±1.42%. The morphology of the capsules showed rough surface texture with minimal pores. The amorphous natures of the nano-capsules was obvious from X-ray diffraction patterns. DSC studies showed high thermal stability of the nano-capsules between 20–120 °C. In vitro release studies revealed that controlled release from the nano-capsules could be achieved using isabgol fiber as encapsulant. However it was observed that the nano-capsules followed a non-Fickian diffusion pattern. Good DPPH-radical scavenging and metal-chelation activities were observed for encapsulated carotenoids. Shelf-life studies showed that the nano-capsules gradually degraded at 97% relative humidity, as the moisture-induced rancidity was evidently not extensive. [ABSTRACT FROM AUTHOR]

Background: Ferula assa-foetida is one of the common medicines that was used as antiseptic with a view to traditional uses, it can be used as a safe and effective drug to treat diseases particularly resistant bacterial infections. This study aims to product gelatin nano- capsules containing Ferula assa-foetida essential oil and investigate their antioxidant and antibacterial activities. Materials and Methods: This experimental study was performed on gelatin nano-capsules containing Ferula assa-foetida essential oil (FAO) (2, 4, 6 and 8% w/w), glycerol (25% w/w) as plasticizer and glutaraldehyde as cross-linker. The morphology, antioxidant and antibacterial activities and operation of the nano-capsules were assessed according to American Standards by Scanning Electron Microscopy, ABTS, and microbiological tests. Results: Gelatin nano-capsules exhibited low antioxidant and antibacterial activities while gelatin nano-capsules incorporated with FAO exhibited excellent antioxidant and antibacterial. The highest rates of these effects were seen merged with 8% of FAO. Conclusion: Gelatin nano-capsules merged with FAO have excellent physical form, as well as they are an appropriate antioxidant and antibacterial that have been considered to produce antoxidant and antibacterial drugs. [ABSTRACT FROM AUTHOR]

A drug delivery system is defined as a formulation or a device that enables the introduction of a therapeutic substance into the body and improves its efficacy and safety by controlling the rate, time, and place of release of drugs in the body. This process includes the administration of the therapeutic product, the release of the active ingredients by the product, and the subsequent transport of the active ingredients across the biological membranes to the site of action. Drug delivery systems aim to improve patient compliance and convenience, such as, for example, fast-dissolving tablets. One of the most important goals of pharmaceutical science is localizing the pharmacological activity of the drug at the site of action. Drug delivery systems are molecular tools which, without undesired interactions at other sites, target a specific drug receptor. Keeping in view the advantages of the delivery system, rapidly disintegrating dosage forms have been successfully commercialized, and, because of increased patient demand, these dosage forms are expected to become more popular. Modern drug delivery technology has been made possible by advances in polymer science. These advances have resulted in polymers with unique properties. Drug delivery systems are made from a variety of organic and inorganic compounds such as polymers, lipids (liposomes, nanoemulsions, and solid-lipid nanoparticles), self-assembling amphiphilic molecules, dendrimers, and inorganic nanocrystals. In addition, hydrogels are novel delivery systems that have attracted much attention in current pharmaceutical research. [ABSTRACT FROM AUTHOR]

The layer-by-layer approach is a highly versatile method for the fabrication of multilayered polymeric films and capsules. It has been widely investigated in research for various polyelectrolyte pairs and core template particles. However, the fabrication of nano-sized capsules at the larger scale is difficult and time consuming, due to the necessity of washing and centrifugation steps before the deposition of each polyelectrolyte layer. This results not only in a very long fabrication time, but also in the partial loss of particles during those intermediate steps. In this study, we introduced a continuous approach for the fabrication of multilayer polyelectrolyte based nano-capsules using calcium phosphate core nanoparticles and a tubular flow type reactor with the potential for synthesizing tens of milligrams of capsules per hour. Adsorption of the polyelectrolyte layer occurred in the tubing where particles and polyelectrolyte solution of choice were mixed, creating a layer of polyelectrolyte on the particles. After this, these newly surfaced-modified particles passed into the next segment of tubing, where they were mixed with a second polyelectrolyte of opposite charge. This process can be continuously repeated until the desired number of layers is achieved. One potential problem with this method concerned the presence of any excess polyelectrolyte in the tubing, so careful control of the amount of polymer added was crucial. It was found that slightly under dosing the amount of added polyelectrolyte ensured that negligible unadsorbed polyelectrolyte remained in solution. The particles created at each deposition step were stable, as they all had a zeta potential of greater than ±25mV. Furthermore the zeta potential measurements showed that charge reversal occurred at each stage. Having achieved the necessary number of polyelectrolyte layers, the calcium phosphate cores were easily removed via dissolution in either hydrochloric or acetic acid., (Copyright © 2016 Elsevier Inc. All rights reserved.)