Core-shell Nanocapsules Research Articles

Spontaneous Fusion of Core-Shell Nanocapsules with Oil Cores and Oppositely Charged Polysaccharide Shells.

Polymer nanocapsules with hydrophobic cores are promising candidates for nanoreactors to carry out (bio)chemical reactions mimicking the performance of natural cellular systems. Their architecture allows reagents to be encapsulated in the cores enabling reactions to proceed in confined environments in a controlled, and efficient manner. Polysaccharide-shell oil-core nanocapsules are proposed here as facile mergeable nanoreactors. Spontaneous fusion of oppositely charged polysaccharide capsules is demonstrated for the first time. Such capsules are formed and easily loaded with reagents by nanoemulsification of an aqueous solution of hydrophobically modified polysaccharides (chitosan, hyaluronate) and oleic acid with dissolved desired hydrophobic compounds. Efficient fusion of the formed nanocapsules dispersed in an aqueous medium at optimized conditions (pH, ionic strength) is followed using fluorescence microscopy by labeling both their cores and shells with fluorescent dyes. As a proof of concept, a model fluorogenic synthesis is also realized by fusing the capsules containing separated reagents and the catalyst. The nanocapsules and fusion process developed here establish a platform for realization of versatile reactions in a confined environment including model studies on biologically relevant processes taking place in natural systems.

Enhanced interfacial polarization through the conversion of Co@C into Co@Co1−xS@C nanocapsules utilizing a facile sulfidation process

The design and development of efficient Co-based electromagnetic (EM) absorbents with double-shell structures have received relatively less attention in the literature. The construction of multiple heterointerfaces gives rise to a unique morphology that holds significant potential in expanding the absorbing frequency range. Co@Co1−xS@C nanocapsules (NCs) with Co as the cores, Co1−xSx and C as the middle and outside shells separately, were successfully prepared using a facile two step process: synthesizing Co@C core–shell NCs by arc-discharge method and subsequently converting them into Co@Co1−xS@C NCs through chemical sulfidation reaction. The experimental results indicate that the thickness of the carbon shell exhibits a decreasing trend (from 1 ± 0.1 nm to 0.6 ± 0.02 nm) following the post-sulfidation process, lasting for approximately two hours. The defect density of the carbon shell also declines from 1.88 × 1011 cm−2 to 1.14 × 1011 cm−2. The reduction in thickness of the carbon shell and the formation of new Co1-xS not only enable efficient manipulation of impedance matching between the dielectric shells and magnetic cores but also facilitate the construction of multiple interfacial polarizations. The study provides evidence that the multi-interfacial Co@Co1−xS@C nanocomposite serves as an effective EM absorbent achieving a minimum reflection loss (RL) up to –78.6 dB at a thickness of merely 1.52 mm within the frequency range of 2~18 GHz.

Tailoring Properties of Hyaluronate-Based Core-Shell Nanocapsules with Encapsulation of Mixtures of Edible Oils.

Dispersions of core-shell nanocapsules (nanoemulsion) composed of liquid oil cores and polysaccharide-based shells were fabricated with emulsification using various mixtures of edible oils and amphiphilic hyaluronate derivatized with 12-carbon alkyl chains forming the shells. Such nanocapsules, with typical diameters in the 100-500 nm range, have been previously shown as promising carriers of lipophilic bioactive compounds. Here, the influence of some properties of the oil cores on the size and stability of the capsules were systematically investigated using oil binary mixtures. The results indicated that, in general, the lower the density, viscosity, and interfacial tension (IFT) between the oil and aqueous polymer solution phases, the smaller the size of the capsules. Importantly, an unexpected synergistic reduction of IFT of mixed oils was observed leading to the values below the measured for individual oils. Such a behavior may be used to tailor size but also other properties of the nanocapsules (e.g., stability, solubility of encapsulated compounds) that could not be achieved applying just a single oil. It is in high demand for applications in pharmaceutical or food industries and opens opportunities of using more complex combinations of oils with more components to achieve an even further reduction of IFT leading to even smaller nanocapsules.

In Vitro Cytotoxicity and In Vivo Antitumor Activity of Lipid Nanocapsules Loaded with Novel Pyridine Derivatives.

This study demonstrates high drug-loading of novel pyridine derivatives (S1-S4) in lipid- and polymer-based core-shell nanocapsules (LPNCs) for boosting the anticancer efficiency and alleviating toxicity of these novel pyridine derivatives. The nanocapsules were fabricated using a nanoprecipitation technique and characterized for particle size, surface morphology, and entrapment efficiency. The prepared nanocapsules exhibited a particle size ranging from 185.0 ± 17.4 to 223.0 ± 15.3 nm and a drug entrapment of >90%. The microscopic evaluation demonstrated spherical-shaped nanocapsules with distinct core-shell structures. The in vitro release study depicted a biphasic and sustained release pattern of test compounds from the nanocapsules. In addition, it was obvious from the cytotoxicity studies that the nanocapsules showed superior cytotoxicity against both MCF-7 and A549 cancer cell lines, as manifested by a significant decrease in the IC50 value compared to free test compounds. The in vivo antitumor efficacy of the optimized nanocapsule formulation (S4-loaded LPNCs) was investigated in an Ehrlich ascites carcinoma (EAC) solid tumor-bearing mice model. Interestingly, the entrapment of the test compound (S4) within LPNCs remarkably triggered superior tumor growth inhibition when compared with either free S4 or the standard anticancer drug 5-fluorouracil. Such enhanced in vivo antitumor activity was accompanied by a remarkable increase in animal life span. Furthermore, the S4-loaded LPNC formulation was tolerated well by treated animals, as evidenced by the absence of any signs of acute toxicity or alterations in biochemical markers of liver and kidney functions. Collectively, our findings clearly underscore the therapeutic potential of S4-loaded LPNCs over free S4 in conquering EAC solid tumors, presumably via granting efficient delivery of adequate concentrations of the entrapped drug to the target site.

Oral docetaxel delivery with cationic polymeric core-shell nanocapsules: In vitro and in vivo evaluation

Oral docetaxel delivery with cationic polymeric core-shell nanocapsules: In vitro and in vivo evaluation

Core-Shell Type Lipidic and Polymeric Nanocapsules: the Transformative Multifaceted Delivery Systems.

Amongst the several nano-drug delivery systems, lipid or polymer-based core-shell nanocapsules (NCs) have garnered much attention of researchers owing to its multidisciplinary properties and wide application. NCs are structured core-shell systems in which the core is an aqueous or oily phase protecting the encapsulated drug from environmental conditions, whereas the shell can be lipidic or polymeric. The core is stabilized by surfactant/lipids/polymers, which control the release of the drug. The presence of a plethora of biocompatible lipids and polymers with the provision of amicable surface modifications makes NCs an ideal choice for precise drug delivery. In the present article, multiple lipidic and polymeric NC (LNCs and PNCs) systems are described with an emphasis on fabrication methods and characterization techniques. Far-reaching applications as a carrier or delivery system are demonstrated for oral, parenteral, nasal, and transdermal routes of administration to enhance the bioavailability of hard-to-formulate drugs and to achieve sustained and targeted delivery. This review provide in depth understanding on core-shell NC's mechanism of absorption, surface modification, size tuning, and toxicity moderation which overshadows the drawbacks of conventional approaches. Additionally, the review shines a spotlight on the current challenges associated with core-shell NCs and applications in the foreseeable future.

Innovative bifunctional heat storage nanocapsules containing polymerizable surfactant for antimicrobial thermoregulating clothes

Bifunctional poly(methyl methacrylate)/Rubitherms®27 (PMMA/RT27) nanocapsules were fabricated by miniemulsion polymerization using poly(2-methacryloyloxy dodecyl dimethyl ammonium chloride-4-allyloxy-2-hydroxy benzophenone)-block-polymethyl methacrylate-iodide (P(QAC12-BP)-b-PMMA-I) as a polymerizable surfactant. Approximately 50-nm spherical core-shell nanocapsules were formed with a highly positive surface charge (≥ +70 mV) derived from the quaternary ammonium (QA) groups in QAC12 units. The QA groups distributed on the nanocapsules’ surfaces effectively presented cationic characteristics and antimicrobial performance. High RT27 loading and encapsulation efficiency PMMA nanocapsules were produced using an MMA: RT27 ratio of 50: 50 with high latent heats of the encapsulated RT27, close to those of the pristine ones. Because of the existence of the BP unit in the polymerizable surfactant located on nanocapsules’ surfaces, the obtained nanocapsules were strongly coated on cotton fabrics by irradiation with UV light, giving them greater washing durability than using an external binder. The coated fabrics exhibited effective antimicrobial performance against S. epidermidis and C. glutamigum. Therefore, the fabricated PMMA/RT27 nanocapsules presenting thermoregulating and antimicrobial properties are well suited for application on textiles.

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BiopolymersVolume 113, Issue 6 e23446 COVER IMAGEFree Access Cover Image First published: 23 June 2022 https://doi.org/10.1002/bip.23446AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Ropinirole hydrochloride (RH) is a promising anti-Parkinson's disease drug but suffers from low-clinical potency, often attributed to poor oral bioavailability, short plasma half-life and metabolism by the liver. Darwish et al. report the preparation of two nanoformulations to enhance delivery of RH to the brain: a self-assembled core-shell nanocapsule of RH and methoxy poly(ethylene glycol)-b-poly(caprolactone) coated with chitosan, and a RH-loaded chitosan-alginate polyelectrolyte nanocomplex. The mucoadhesive properties endowed by the chitosan and alginate promote RH delivery across the nasal mucosa and higher brain uptake of RH is seen in albino mice when the formulations are administered intranasally compared with intravenously. DOI: 10.1002/bip.23489 Volume113, Issue6June 2022e23446 RelatedInformation

PH-responsive delivery of rebaudioside a sweetener via mucoadhesive whey protein isolate core-shell nanocapsules

Rebaudioside (Reb A) is a natural high-intensity sweetener available for commercial use. Its application has been hampered, however, by its unnatural sweetness profile and a bitter aftertaste at higher concentration thresholds. The goal of this research was to mitigate these shortcomings by increasing the sweetening power, thus lowering the amount needed to achieve the desired sweetness, specifically in acidic liquid media. We achieved the stated goal via the fabrication of a mucoadhesive delivery vehicle that can be retained on the tongue mucosa and allowed for a more targeted and prolonged release of the sweetener near the taste bud. We have chosen hydrolyzed whey protein isolate and pectin as shell materials and crosslinked them via an ultrasonic process. In the pursuit of our goal, we found that WPI-Pectin was the most suitable of all the protein-polysaccharide combinations tested, yielding nanocapsules with average particle sizes of 393 nm and polydispersity index (PDI) of 0.43. These capsules could be resuspended in water with ζ-potential of −20.4 mV. The WPI-pectin system was also shown to be twice as effective at depositing Reb A to the surface of the tongue as regular sweetener solution. Finally, we have demonstrated that WPI and pectin capsules can achieve a desirable pH-responsive profile for application in beverages with minimal release in acidic conditions (7.1 %) and higher release in neutral conditions (19.5 %).

Silica-Based Core-Shell Nanocapsules: A Facile Route to Functional Textile

In this work, we present a surfactant-free miniemulsion approach to obtain silica-based core-shell nanocapsules with a phase change material (PCM) core via in-situ hydrolytic polycondensation of precursor hyperbranched polyethoxysiloxanes (PEOS) as silica shells. The obtained silica-based core-shell nanocapsules (PCM@SiO2), with diameters of ~400 nm and silica shells of ~14 nm, reached the maximum core content of 65%. The silica shell had basically no significant influence on the phase change behavior of PCM, and the PCM@SiO2 exhibited a high enthalpy of melt and crystallization of 123–126 J/g. The functional textile with PCM@SiO2 has been proposed with thermoregulation and acclimatization, ultraviolet (UV) resistance and improved mechanical properties. The thermal property tests have shown that the functional textile had good thermal stability. The functional textile, with a PCM@SiO2 concentration of 30%, was promising, with enthalpies of melting and crystallization of 27.7 J/g and 27.8 J/g, and UV resistance of 77.85. The thermoregulation and ultraviolet protection factor (UPF) value could be maintained after washing 10 times, which demonstrated that the functional textile had durability. With good thermoregulation and UV resistance, the multi-functional textile shows good prospects for applications in thermal comfort and as protective and energy-saving textile.

Heat-induced spontaneous and damage-free separation of transparent polymer thin films based on clickable decomposition of pyrolytic core-shell nanocapsules

The automatic and damage-free manipulation for efficient separation of polymer thin films from various substrates has received growing interests in a broad range of applications from electronic devices to optical films because it can realize the innovative recycling and on-demand spontaneous detachment of scarce and valuable materials. Herein, we demonstrate a spontaneous and damage-free separation methodology for transparent polymer thin films based on the heat-induced microbubble generation from pyrolytic core-shell nanocapsules at the interface between the substrate and the thin film. The pyrolytic polymer nanocapsules were fabricated by encapsulating a latent gas-forming agent of benzenesulfonyl hydrazine in the crosslinked copolymer nanoparticle comprising polyacrylonitrile and poly(methyl methacrylate). The heat-induced clickable decomposition of pyrolytic core-shell nanocapsules generated a significant number of microbubbles inside the thin film, thereby inducing instantaneous and effortless detachment of the transparent film from substrate. The fabricated polymer thin films embedded with a small number of pyrolytic polymer nanocapsules afforded an excellent debonding performance with a maximum efficiency of 93.4% after short thermal treatment compared to that of the pristine thin films, simultaneously maintaining a remarkable optical clarity of about 99% and a high initial adhesion strength with a maximum of approximately 22 kgf cm−2.

Effective Detection of Nafion®-Based Theranostic Nanocapsules through 19F Ultra-Short Echo Time MRI.

The application of the Three-Dimensional Ultra-Short Echo Time (3D UTE)pulse sequence at a high magnetic field for visualization of the distribution of 19F loaded theranostic core-shell nanocapsules with Nafion® (1,1,2,2-tetrafluoroethene; 1,1,2,2-tetrafluoro-2- [1,1,1,2,3,3-hexafluoro-3-(1,2,2-trifluoroethenoxy)propan-2-yl] oxyethanesulfonic acid) incorporated into the shell is presented. The nanocarriers were formed via the layer-by-layer technique with biodegradable polyelectrolytes: PLL (Poly-L-lysine), and with Nafion®: polymer with high 19F content. Before imaging, an MR (magnetic resonance) spectroscopy and T1 and T2 measurements were performed, resulting in values of T2 between 1.3 ms and 3.0 ms, depending on the spectral line. To overcome limitations due to such short T2, the 3D UTE pulse sequence was applied for 19F MR imaging. First Nafion® solutions of various concentrations were measured to check the detection limit of our system for the investigated molecule. Next, the imaging of a phantom containing core-shell nanocapsules was performed to assess the possibility of visualizing their distribution in the samples. Images of Nafion® containing samples with SNR ≥ 5 with acquisition time below 30 min for 19F concentration as low as 1.53 × 10−2 mmol 19F/g of sample, were obtained. This is comparable with the results obtained for molecules, which exhibit more preferable MR characteristics.

Improved anti-Cutibacterium acnes activity of tea tree oil-loaded chitosan-poly(ε-caprolactone) core-shell nanocapsules

The purpose of this study was to develop tea tree oil (TTO)-loaded chitosan-poly(ε-caprolactone) core-shell nanocapsules (NC-TTO-Ch) aiming the topical acne treatment. TTO was analyzed by gas chromatography-mass spectrometry, and nanocapsules were characterized regarding mean particle size (Z-average), polydispersity index (PdI), zeta potential (ZP), pH, entrapment efficiency (EE), morphology by Atomic Force Microscopy (AFM), and anti-Cutibacterium acnes activity. The main constituents of TTO were terpinen-4-ol (37.11 %), γ-terpinene (16.32 %), α-terpinene (8.19 %), ρ-cimene (6.56 %), and α-terpineol (6.07 %). NC-TTO-Ch presented Z-average of 268.0 ± 3.8 nm and monodisperse size distribution (PdI < 0.3). After coating the nanocapsules with chitosan, we observed an inversion in ZP to a positive value (+31.0 ± 1.8 mV). This finding may indicate the presence of chitosan on the nanocapsules' surface, which was corroborated by the AFM images. In addition, NC-TTO-Ch showed a slightly acidic pH (∼5.0), compatible with topical application. The EE, based on Terpinen-4-ol concentration, was approximately 95 %. This data suggests the nanocapsules' ability to reduce the TTO volatilization. Furthermore, NC-TTO-Ch showed significant anti-C. acnes activity, with a 4× reduction in the minimum inhibitory concentration, compared to TTO and a decrease in C. acnes cell viability, with an increase in the percentage of dead cells (17 %) compared to growth control (6.6 %) and TTO (9.7 %). Therefore, chitosan-poly(ε-caprolactone) core-shell nanocapsules are a promising tool for TTO delivery, aiming at the activity against C. acnes for the topical acne treatment.

Uptake and in vitro anticancer activity of oleic acid delivered in nanocapsules stabilized by amphiphilic derivatives of hyaluronic acid and chitosan

The nanoemulsion-based delivery systems have gained particular attention due to effective encapsulation and protection of hydrophobic active compounds. However, several features like limited stability, cellular uptake or release of payloads still need to be addressed. We investigated the uptake of the nanocapsules based on the amphiphilic derivative of hyaluronate with oleic acid cores (oil-in-water nanoemulsion) and their anticancer activity in vitro. The core-shell nanocapsules exhibiting long term stability in dispersion showed an enhanced uptake by cancer cells and effectively killed them only if composed of hyaluronate-based shells and oleic acid cores - the anionic chitosan-based shells and/or corn oil cores were used for control experiments. We concluded that the nanocapsules stabilized by the amphiphilic derivative of hyaluronic acid may serve as very stable and efficient delivery systems for oil-soluble compounds without necessity of application of low molecular weight (co)surfactants. The in vitro studies indicated anticancer activity of such delivered oleic acid and crucial role of hyaluronate shell of the nanocapsules in its efficient delivery and enzyme-triggered disintegration inside cells. Corn oil was shown as a nutrient that can serve as an inert vehicle in the studied nanoemulsion that exhibit application potential in food, dietary supplement industry and medicine.

Facile separation of optically transparent adhesive films by heat-triggered gas generation of vaporizable core–shell nanocapsules embedded with benzenesulfonyl hydrazide

A simple and effective separation methodology for separating optically transparent adhesive films without damaging the substrate is presented here. Evaporable core–shell nanocapsules embedded with benzenesulfonyl hydrazide were introduced into acrylic films, and could generate nitrogen gas by thermal treatment, inducing the facile separation of the adhesive thin films from the substrate. The heat-triggered gas generation of surface-confined vaporizable nanocapsules created the interfacial openings between the thin film and substrate, and thus accelerated the selective and clear detachment of thin films. In addition, the nanocapsule-embedded adhesive films exhibited the high optical clarity for display applications.

Active Encapsulation in Biocompatible Nanocapsules.

Co-precipitation is generally refers to the co-precipitation of two solids and is widely used to prepare active-loaded nanoparticles. Here, it is demonstrated that liquid and solid can precipitate simultaneously to produce hierarchical core-shell nanocapsules that encapsulate an oil core in a polymer shell. During the co-precipitation process, the polymer preferentially deposits at the oil/water interface, wetting both the oil and water phases; the behavior is determined by the spreading coefficients and driven by the energy minimization. The technique is applicable to directly encapsulate various oil actives and avoid the use of toxic solvent or surfactant during the preparation process. The obtained core-shell nanocapsules harness the advantage of biocompatibility, precise control over the shell thickness, high loading capacity, high encapsulation efficiency, good dispersity in water, and improved stability against oxidation. The applications of the nanocapsules as delivery vehicles are demonstrated by the excellent performances of natural colorant and anti-cancer drug-loaded nanocapsules. The core-shell nanocapsules with a controlled hierarchical structure are, therefore, ideal carriers for practical applications in food, cosmetics, and drug delivery.

Effortless separation of transparent adhesive films using phase-change core-shell nanocapsules

Effortless separation without damage to the substrates is highly advantageous for the recovery and recycling of expensive electronic components in display devices. In this study, we present an approach for separating transparent adhesive films from substrates using phase-change core-shell nanocapsules. The nanocapsules are prepared from poly(methyl methacrylate) (PMMA) nanoparticles via the encapsulation of methylcyclohexane (MCH). The evaporated MCHs facilitated the detachment of adhesive films through micro-bubble generation after thermal treatment, leading to the effortless separation of the adhesive layer. The newly fabricated adhesive film with phase-change nanocapsules resulted in high transmittance, with an excellent debonding efficiency after thermal treatment.

Enhanced high-frequency microwave absorption in core-shell nanocapsules with atomic-scale oxygen substitutions

High-performance electromagnetic wave absorption materials constitute key components of microelectronic devices. Traditional absorbents possess magnetic losses and/or dielectric losses, while the experimental approach for their simultaneous enhancement is still lacking. Here, we demonstrate that the core/shell structural Ni@C nanocapsules, functionalized by atomic-scale oxygen substitutions that can be formed catalytically by highly defective graphitic structure, present enhanced dielectric loss capacities at gigahertz. In particular, &amp;gt;90% of the microwave energy could be attenuated for a planar absorber with a thickness down to 1–1.5 mm at 7.6–13.8 GHz. Experimental characterizations coupled with density functional theory calculations further evidence that the capacity enhancement is ascribed to the structure breaking at the heterogeneous substitutional zones, resulting in the intrinsic polarization of carbon–oxygen heterostructures. The present study shows a new mentality of designing for optimizing electromagnetic wave absorption materials and also has pointed out the atomic-scale structural origin of the electromagnetic response performance.

Recent Advancements in the Use of Aerosol-Assisted Atmospheric Pressure Plasma Deposition

Atmospheric pressure plasma allows for the easy modification of materials’ surfaces for a wide range of technological applications. Coupling the aerosol injection of precursors with atmospheric pressure plasma largely extends the versatility of this kind of process; in fact solid and, in general, scarcely volatile precursors can be delivered to the plasma, extending the variety of chemical pathways to surface modification. This review provides an overview of the state of the art of aerosol-assisted atmospheric pressure plasma deposition. Advantages (many), and drawbacks (few) will be illustrated, as well as hints as to the correct coupling of the atomization source with the plasma to obtain specific coatings. In particular, the deposition of different organic, hybrid inorganic–organic and bioactive nanocomposite coatings will be discussed. Finally, it will be shown that, in particular cases, unique core–shell nanocapsules can be obtained.

Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon

HighlightsThe crystalline Fe/MnO@C core–shell nanocapsules embedded in porous amorphous carbon matrix (FMCA) was prepared by a novel confinement strategy of modified arc-discharge method.The heterogeneous crystalline–amorphous nanocrystals disperse evenly and exhibit improvement of static magnetization and excellent electromagnetic absorption properties.The adding MnO2 confines degree of graphitization and contributes to form amorphous carbon. Dielectric loss and microwave absorption are achieved adjustable.