Polymer Shell Research Articles

Camouflaged Virus-Like-Nanocarrier with a Transformable Rough Surface for Boosting Drug Delivery.

Due to non-specific strong nano-bio interactions, it is difficult for nanocarriers with permanent rough surface to cross multiple biological barriers to realize efficient drug delivery. Herein, a camouflaged virus-like-nanocarrier with a transformable rough surface is reported, which is composed by an interior virus-like mesoporous SiO2 nanoparticle with a rough surface (vSiO2 ) and an exterior acid-responsive polymer. Under normal physiological pH condition, the spikes on vSiO2 are hidden by the polymer shell, and the non-specific strong nano-bio interactions are effectively inhibited. While in the acidic tumor microenvironment, the nanocarrier sheds the polymer camouflage to re-expose its rough surface. So, the retention ability and endocytosis efficiency of the nanocarrier are great improved. Owing to it's the dynamically variable rough surface, the rationally designed nanocarrier exhibits extended blood-circulation-time and enhanced tumor accumulation.

Direct continuous synthesis of macroRAFT-grafted Fe3O4 nanoclusters for the preparation of magnetic nanocomposites

A new method for synthesizing magnetic nanocomposite latex particles with a significant magnetic response and high coating rate is reported herein. Based on a micro-flow platform, Fe3O4 nanoclusters grafted with macroRAFT agents were continuously synthesized within 90 s. The obtained clusters present high mono-dispersity, narrow size distribution, and excellent saturation magnetization. Moreover, the macroRAFT polymer chains grafted on the surface of the nanoclusters can be reactivated for polymerizing hydrophobic monomers without using any surfactant, to achieve the coating of magnetic particles. The resulting polymer shell can protect the magnetic core and maintain a substantial magnetic response. Furthermore, by optimising the reaction conditions, the encapsulation efficiency can be significantly improved for the efficient preparation of magnetic nanocomposites.

Inverse design of programmable Poisson's ratio and in-plane stiffness for generalized four-fold origami

Origami-inspired metamaterials and structures exhibit extraordinary properties, including programmable Poisson's ratio and tunable stiffness. Although some research has achieved the programmability of generalized four-fold origami structures, the proposed formulas of Poisson's ratio and stiffness are complex and difficult to be applied for inverse design of origami engineering. Here, the geometric mechanics of a generalized four-fold origami unit with three angles and two lengths controls are studied. The analytical formulas give a great potential of inverse design for in-plane Poisson's ratio and in-plane stiffness. To realize inverse design, the transcendental equation with uninvertible solution is simplified by polynomial fitting method. Moreover, the results are verified by the classical Miura origami results, the existing Origami Simulator tools and the physical polyethylene models. Finally, to make the proposed inverse design applicable to non-zero thickness origami, it is recommended to adopt carbon fiber reinforced polymer shell as the connection of the panel.

Foreword to the special issue on new developments in structural stability.

Foreword to the special issue on new developments in structural stability.

Antitumor Effects of Microencapsulated Gratiola officinalis Extract on Breast Carcinoma and Human Cervical Cancer Cells In Vitro

Flavonoid-containing Gratiola officinalis extract has been studied in relation to breast carcinoma and human cervical cancer cells in encapsulated and native form. Encapsulation was realized in polymer shells, which were formed by the layer-by-layer method using sequential adsorption of poly(allylamine hydrochloride) and poly(sodium 4-styrenesulfonate) on the destructible cores. The extract was prepared by the author's method and characterized using high performance liquid chromatography. By means of optical and fluorescent microscopy, cell changes under the action of pure and encapsulated extracts were comprehensively studied, and statistical analysis was carried out. Cells were stained with propidium iodide, acridine orange, and Hoechst 33258. A fluorescence microscope with a digital video camera were used for cell imaging. The encapsulated extract caused 100% death of breast cancer SKBR-3 cells and 34% death of cervical cancer HeLa cells and prevented the formation of autophagosomes in both cultures. Analysis of the viability and morphological features of tumor cells under the action of microencapsulated extract allows us to consider microencapsulation as an effective strategy for delivering Gratiola officinalis extract to tumor cells and a promising way to overcome the protective autophagy.

Toward MOF@Polymer Core-Shell Particles: Design Principles and Potential Applications.

ConspectusCompositing MOFs with polymers brings out the best properties of both worlds. The solubility and excellent mechanical properties of polymers endow the brittle, powdery MOFs with enhanced processability, thereby enriching their functions as solid sorbents, filters, membranes, catalysts, drug delivery vehicles, and so forth. While most MOF-polymer composites are random mixtures of two materials with little control over their fine structures, MOF@polymer core-shell particles have recently emerged as a new platform for precise composite design. The well-defined polymer coating can keep the rich pore characteristics of the MOF intact while furnishing the MOF with new properties such as improved dispersibility in various media, tunable surface energy, enhanced chemical stability, and regulated guest diffusion. Nevertheless, the structural and chemical complexity of MOFs poses a grand challenge to the development of a generalizable and feasible strategy for constructing MOF@polymer. Examples in the literature that showcase the presence of a well-defined polymer shell on the MOF with fully reserved porosity are rare. Moreover, methods for coating MOFs with condensation polymers (e.g., polyimide, polysulfone) are severely underexplored, despite their clear potential as membrane materials. In this Account, we present our group's effort over the past 4 years on the synthesis and applications of MOF@polymer composites. We first described a highly generalizable surface polymerization method that utilizes the rapid physisorption of a random copolymer (RCP) to carry initiating groups to the MOF surfaces. Subsequent controlled radical polymerization led to the formation of a uniform methacrylate or styrenic polymer on the MOF with tunable thickness and composition. To utilize the properties of condensation polymers, we pioneered the covalent grafting of polyimide (PI) brushes to UiO-66-NH2 surfaces. In addition, to circumvent the need for a covalent anchoring group, we further developed an MOF surface grafting method based on mechanical linkage. Instead of connecting to the ligand, polyimide (PI) oligomer was linked to a functionalized linear polymer physically entangled within an MOF, thus realizing surface grafting with PI. Alternatively, PIs, polysulfone (PSF), and polycarbonate (PC) can also be grafted to various MOF surfaces through a metal-organic nanocapsule (MONC)-mediated method using a combination of electrostatic interaction and coordination bonds. To find a rapid and low-cost surface coating method suitable for commercialization, a new approach called non-solvent-induced surface-aimed deposition (NISAP) was developed. The action of the solvent phase separation drives dianhydrides and polyamines to the MOF surface, thus realizing accelerated polymerization and the rapid formation of a polymer coating on the MOF. Finally, we provided an overview of the unique properties and potential applications of MOF@polymer composites, including improved stability, MMMs, porous liquids (PLs), and immobilizing homogeneous catalysts. We hope that this Account can inspire more researchers to further develop and optimize the synthetic strategies for MOF@polymer and uncover its full application potential.

Core–Shell Polymeric Nanostructures with Intracellular ATP-Fueled dsRNA Delivery toward Genetic Control of Insect Pests

Transgenic RNA interference (RNAi) represents a burgeoning and promising alternative avenue to manage plant diseases and insect pests in plants. Nonviral nanostructured dsRNA carriers have been demonstrated to possess great potential to facilitate the application of RNAi. However, it remains a critical challenge to achieve the targeted and effective release of dsRNA into the pest cells, limiting the efficiency of the biological control of pests and diseases in practical applications. In this study, we designed and constructed a new type of core-shell polymeric nanostructure (CSPN) with controllable structure, eco-friendliness, and good biocompatibility, on which dsRNA can be efficiently loaded. Once loaded into CSPNs, the dsRNA can be effectively prevented from nonsense degradation by enzymes before entering cells, and it shows targeted and image-guided release triggered by intracellular ATP, which significantly increases the efficiency of gene transfection. Significantly, the in vivo study of the typical lepidoptera silkworm after oral feeding demonstrates the potential of dsCHT10 in CSPNs for a much better knockdown efficiency than that of naked dsCHT10. This innovation enables the nanotechnology developed for the disease microenvironment-triggered release of therapeutic genes for application in sustainable crop protection.

Visible light-based polymerization of poly (methyl methacrylate) encapsulated fragrances used for fabric softener applications

A visible-light-based photopolymerization is an attractive approach for encapsulating volatile essential oils with low aqueous solubility and stability. This research aimed to encapsulate pink fruity fragrance (PF) and white floral fragrance (WF) with poly (methyl methacrylate) (PMMA), termed respectively as PF-PMMA and WF-PMMA, through photopolymerization under blue-light emitting diodes (LEDs) exposure. The PF-PMMA and WF-PMMA were used in fabric softeners to provide a long-lasting fragrance to the fabric. The wavelength of the blue-LEDs light was 410–530 nm, while camphorquinone and ethyl 4-(dimethylamino) benzoate were used as co-photoinitiators. The effect of the mixing ratio between polymer shell and core material on particle size, conversion, and encapsulation efficiency of WF-PMMA and PF-PMMA was investigated. The size of the prepared WF-PMMA and PF-PMMA microcapsules were 3.1–3.7 µm and 2.1–2.3 µm, respectively. These microcapsules were added to fabric softeners and applied to TC fabric. The highest encapsulation efficiency and conversion of WF-PMMA and PF-PMMA were 95.7 ± 0.1 %, 93.5 ± 2.4 %, 89.4 ± 1.0 %, and 74.1 ± 4.2 %, respectively. It was also found that the fragrances remaining in the fabrics after 30 d storage was 54.3 % for PF-PMMA and 37 % for WF-PMMA. The results presented the high potential for microencapsulation of fragrances by photopolymerization to prolong the fragrance release duration.

Facile fabrication of polypyrrole/NiOx core‐shell nanocomposites for hydrogen production from wastewater

AbstractThis work highlights testing the polymer nanocomposite for hydrogen gas production from wastewater (sewage water). The in‐situ polymerization technique is used to prepare polypyrrole (PPy) and PPy/NiOx nanocomposite films on a glass substrate. The film's ability to generate hydrogen from sewage water is then evaluated. The XRD and XPS confirmed the formation of two types of NiOX: NiO and Ni2O3. The optical property of the composite is greater than the polymer under the insertion of NiOx as a core for the polymer coating shell, in which the band gap values are 2.25 and 1.81 eV, respectively. The TEM confirmed the PPy/NiOx core‐shell formation, in which the polymer shell (20 nm) coated the NiOX core (170 nm). The electrochemical testing for H2 gas production is carried out through a three‐electrode cell. The effect of light on/off, wavelengths, and temperature on the H2 production is applied. Under off/on light, the produced current density (Jph) value is enhanced from 5 to 16 μA, respectively. The effect of monochromatic light: 440, 540, and 730 nm are tested, and the produced Jph values are −1.28, −1.16, and −1.14 μA cm−2, respectively. In which, the decreasing Jph value with increasing of the monochromatic light confirmed the behavior of the photoelectrode under different optical regions. The Jph values increase from −1.6 to −5.8 μA cm−2 with a rise in temperature from 30 to 55°C. Moreover, enthalpy (ΔH*), activation energy (Ea), and entropy (ΔS*) of thermodynamic processes are determined using the photoelectrode response at different temperatures.

Hyper-Cross-Linked Nanoparticle Reinforced Composite Polymer Electrolytes with Enhanced Ionic Conductivity and Thermal Stability for Lithium-Ion Batteries

Solid polymer electrolytes (SPEs) have been considered as promising substitutes for liquid electrolytes in lithium-ion batteries due to their flexibility and nonflammability. However, there are still significant challenges to be overcome, such as the low ion conductivity and undesirable lithium ion transference number (tLi+). In this study, we prepare poly(ethylene oxide)-based composite solid polymer electrolytes (CSPE-HCPs) using hyper-cross-linked SiO2@PMMA-co-PS nanoparticles as the reinforcement. In contrast to the conventional SPEs, CSPE-HCPs can maintain dimensional thermal stability up to 260 °C. Meanwhile, the ionic conductivity of CSPE-HCPs can be up to 1.13 × 10–4 S cm–1 at 30 °C and the tLi+ can reach 0.51 at room temperature due to the porous hyper-cross-linked polymeric shell. Furthermore, LiFePO4/CSPEs/Li cells possess excellent rate performance and relatively stable cycle performance in addition to their outstanding electrochemical window (up to 5.3 V). It is demonstrated that these solid electrolytes reinforced by hyper-cross-linked composite nanoparticles can be a promising component to improve the performance of all solid-state lithium-ion batteries.

Efficient encapsulation of isocyanates in PCL/PLA biodegradable microcapsules for adhesives

Microencapsulation of isocyanates eliminates the risks associated with their direct handling, protects the isocyanate species from air moisture, and increases the storage life. In light of this, we present a straightforward and efficient process to encapsulate isophorone diisocyanate (IPDI) using biodegradable polymers by an emulsion system combined with the solvent evaporation method. We produced spherical, disaggregated, and core–shell microcapsules (MCs) using poly(ε-caprolactone) (PCL), polylactic acid (PLA), or PCL/PLA blends as shell materials. As far as we know, it is the first time that isocyanate species are encapsulated by PLA or PCL/PLA blends. Our process leads to a production yield of 70–74% and an encapsulated isocyanate content up to 73 wt% of the MCs. All MCs showed very good isocyanate protection, especially when stored in low-moist environments. Their use as cross-linking agents for harmless, eco-innovative, and high-performance adhesive formulations for footwear was tested, for the first time, according to the specifications of industry standards. The peel tests of the adhesive’s joints revealed peeling strength values between 3.45 and 6.09 N/mm which is higher than the minimum required. The creep tests demonstrated that the use of MCs with encapsulated IPDI improves the heat resistance of the adhesive joints. Therefore, the MCs revealed an effective isocyanate release and very capable adhesive joints with no negative effects from the polymeric shell, validating the employment of these cross-linking agents in the footwear industry. Although PCL MCs were the ones with the highest IPDI content, the best adhesive formulations were produced with MCs with a high amount of PLA, due to their smaller size, good dispersibility and better distribution at the substrate.Graphical abstract

Phytoestrogens decorated nanocapsules for therapeutic methionine γ-lyase targeted delivery

The main task of targeted therapy is the selective destruction of cancer cells without affecting normal ones. For these purposes, small molecules and antibodies are used that target specific receptors and proteins or block signaling pathways in tumor cells. The natural phytoestrogens daidzein (Dz) and genistein (Gn) possess binding capacity to estrogen receptors (ER). Methionine γ-lyase (MGL) is promising in two strategies of antitumor therapy: for the elimination of l-methionine, which is necessary for the proliferation of tumor cells, and for the production of cytotoxic dialkyl thiosulfinates in situ. For delivery of MGL-loaded nanocapsules (nanoreactors) to the surface of cancer cells a technique for Dz or Gn incorporation into the shell of polyionic vesicles (PICsomes) was developed. The nanoreactors were characterized by dynamic light scattering and transmission electron microscopy. The enzyme retained its catalytic efficiency inside the decorated PICsomes. The binding of Dz/Gn-nanoreactors to the surface of ER + MCF7 breast adenocarcinoma cells was demonstrated. For the first time an influence of enzyme-loaded PICsomes and their individual components on embryos development was evaluated. The high rate of blastocysts formation (>80%) was observed for all tested components and nanoreactors themselves. A strong inhibitory effect on the early embryonic development of MGL-loaded PICsomes in the presence of S-alkyl-l-cysteine sulfoxide substrates was showed. This proves that the substrates can freely penetrate through the polymer shell of the polyionic vesicle and are cleaved by MGL to form cytotoxic thiosulfinates. The data obtained for phytoestrogens decorated PICsomes may be applied in enzyme therapy of malignant tumors.

Fabrication of a Dual-Drug-Loaded Smart Niosome-g-Chitosan Polymeric Platform for Lung Cancer Treatment.

Changes in weather conditions and lifestyle lead to an annual increase in the amount of lung cancer, and therefore it is one of the three most common types of cancer, making it important to find an appropriate treatment method. This research aims to introduce a new smart nano-drug delivery system with antibacterial and anticancer capabilities that could be applied for the treatment of lung cancer. It is composed of a niosomal carrier containing curcumin as an anticancer drug and is coated with a chitosan polymeric shell, alongside Rose Bengal (RB) as a photosensitizer with an antibacterial feature. The characterization results confirmed the successful fabrication of lipid-polymeric carriers with a size of nearly 80 nm and encapsulation efficiency of about 97% and 98% for curcumin and RB, respectively. It had the Korsmeyer-Peppas release pattern model with pH and temperature responsivity so that nearly 60% and 35% of RB and curcumin were released at 37 °C and pH 5.5. Moreover, it showed nearly 50% toxicity against lung cancer cells over 72 h and antibacterial activity against Escherichia coli. Accordingly, this nanoformulation could be considered a candidate for the treatment of lung cancer; however, in vivo studies are needed for better confirmation.

Preparation of MOF-Based Core-Shell Gel Particles with Catalytic Activity and Their Plugging Performance.

Drilling fluid systems for deep and ultra-deep wells are hampered by both high-temperature downhole environments and lengthy cycle periods. Suppose that the gel particle-plugging agent, the primary treatment agent in the system, fails to offer durable and stable plugging performance. In such a scenario, the borehole wall is susceptible to instability and landslide after prolonged immersion, leading to downhole accidents. In this study, novel core-shell gel particles (modified ZIF) with ZIF particles employed as the core material and organosilicon-modified polyethylene polyamine (PEPA) as the polymer shell were fabricated using PEPA, in-house synthesized (3-aminopropyl) triethoxysilane (APTS), and the ZIF-8 metal-organic framework (MOF) as the raw materials to enhance the long-term plugging performance of gel plugging agents. The modified ZIF particles are nanoscale polygonal crystals and differ from conventional core-shell gel particles in that they feature high molecular sieve catalytic activity due to the presence of numerous interior micropores and mesopores. As a result, modified ZIF exhibits the performance characteristics of both rigid and flexible plugging agents and has an excellent catalytic cross-linking effect on the sulfonated phenolic resin (SMP-3) and sulfonated lignite resin (SPNH) in drilling fluids. Consequently, a cross-linking reaction occurs when SMP-3 and SPNH flow through the spacings in the plugging layer formed by the modified ZIF particles. This increases the viscosity of the liquid phase and simultaneously generates an insoluble gel, forming a particle-gel composite plugging structure with the modified ZIF and significantly enhancing the long-term plugging performance of the drilling fluid.

One-pot preparation of inorganic-organic double-shell microcapsule with good barrier and mechanical property via photopolymerization

Microcapsule has been widely used for fabricating functional coatings. For practical application in coatings, an ideal microcapsule should possess outstanding barrier, thermal and mechanical properties simultaneously. In this paper, a series of double-shell hybrid microcapsule loaded with self-healing agent (linseed oil, LO) with outer inorganic SiO2 shell and inner UV-cured polymeric shell were successfully synthesized via photopolymerization. The obtained double-shell hybrid microcapsule was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The barrier properties, thermal stability and mechanical property of the microcapsules were investigated in detail. Via the adjustment of chemical structure of photo-curable resin and the crosslinking density, the core release of the microcapsule could be reduced to only 2.5 wt% after immersing in organic solvent for 48 h, suggesting the outstanding barrier properties of the double-shell microsphere. The double-shell hybrid microcapsules also possessed outstanding thermal stability, and its initial decomposition temperature increased by about 32 ℃ and 14 ℃ compared with that of mono-shell organic and inorganic microcapsules. Moreover, the Young's modulus and hardness of the double-shell hybrid microcapsules were thirty-fold and forty-fold that of mono-shell organic microcapsules, which proved their excellent mechanical property. And the prepared double-shell hybrid microcapsule could encapsulate LO stably for a long time to avoid its failure, which was successfully employed to the construction of self-healing coatings.

NANOCÁPSULAS DE NÚCLEO LIPÍDICO: PREPARAÇÃO, CARACTERIZAÇÃO E APLICAÇÕES BIOLÓGICAS

LIPID-CORE NANOCAPSULES: PREPARATION, CHARACTERIZATION AND BIOLOGICAL APPLICATIONS. Lipid-core nanocapsules (LNCs) are core-shell structures, in which the core is an organogel formed by a solid lipid dispersed in a triglyceride, and the shell is a polymer. Those nanocapsules encapsulate poorly-water soluble drugs by dispersion in the core and/or interaction with the polymer. The core and the shell act as diffusional barriers differenting the LNC from previously developed polymeric nanocapsules containing an oily core and a polymer shell, which unique diffusional barrier is the shell. In this review, we discuss the supramolecular structure, the physico-chemical characterization, including sizing, surface potential, fluorescent labeling strategies, as well as the interfacial reactions in water to coat and functionalise the LNC surface. Different organometallic complexes have been synthesized to decorate the nanocapsules envisaging the treatment of atherosclerosis, cancer, mucopolysaccharidosis I, and hypertension. We also describe the main applications of the nanoformulations in the pharmaceutical, medical, and veterinary fields, including in vitro and in vivo evaluations of toxicity and efficacy.

VISCOELASTIC PROPERTIES OF FERROFLUIDS WITH CLUSTERED PARTICLES

Clustered (multi-core) magnetic fluids provoke a considerable interest of researchers and practitioners, because they are very promising for various technical and biomedical applications. These fluids contain clusters (clustered particles), which, in turn, consist of ferromagnetic nanoparticles retained together by a polymer shell. The typical size of a cluster varies from a few tens to several hundreds of nanometers, while the sizes of individual single-domain ferroparticles of which it is composed vary from 5 to 12 nm. The rheological phenomena in such fluids (strong magnetorheological effect and slow viscoelastic relaxation) are predetermined by the association of the clustered particles under the action of an external magnetic field into heterogeneous structures and aggregates and the dynamics and disruption of these aggregates in macroscopic deformational flows. In this work, we propose a theoretical model for viscoelastic effects in clustered magnetic fluids. The model is based on the idea of aggregating composite particles into linear chain-like aggregates. In the order of magnitude, the theoretical results agree with experimental data.

Nanoparticles Methods for Hydrophobic Drugs — A Novel Approach: Graphical Abstract

The current scenario shifts the advancement of technology toward nanotechnology as well as nanoparticles (NPs). Both are extensively used in pharmaceutical drug delivery also. NPs play a key role in the encapsulation of hydrophobic as well as hydrophilic drugs into the polymeric shells which leads to an increase in the solubility, absorption, encapsulation, and drug loading capacity of the drugs. The major limitations of hydrophobic drugs are solubility issues which hindered the drug’s bioavailability. These limitations can be overcome by polymeric NPs. Both subtypes of polymeric NPs, i.e., nanosphere and nanocapsules are also for the encapsulation of hydrophobic drugs. Our graphical review focused on hydrophobic drug encapsulation through polymeric NP formulation only via two methods, i.e., nanoprecipitation as well as solvent evaporation methods. Both methods are extensively used for hydrophobic drugs and also hold unique properties. The nanoprecipitation method is a single-step method based upon the nucleation process, whereas the solvent evaporation method is a two-step emulsification method. The present graphical review summarized the available remedies through NPs to increase the solubility of hydrophobic drugs.

Creep of an inhomogeneous polymeric cylindrical shell under heating

The article presents the calculation of a polymer thick-walled cylindrical shell, taking into account creep under the action of a uneven temperature field. The relevance of the work lies in the widespread intro-duction of polymer pipes in the repair and construction of pipelines for heating, sewerage, and water supply systems. The problem is solved in an axisymmetric formulation under plane deformation conditions. The calculation is based on the non-linear Maxwell-Gurevich equation, which is widely used in the calculations of polymer structures. In the problem under consideration, the cylindrical shell is in a flat de-formed state. It is also believed that temperature is a function of radius and time.

Fabrication and properties valuation of Natural fiber and filler-based hybrid-polymer composites

Because of biodegradability, low weight, non-da000nger, instability, decreased condition, contamination, little effort, and simplicity of recyclability, natural fibre polymer composites are now being utilized in place of synthetic fibre reinforced polymer composites. By altering the fibre and epoxy percentages, to find the effect of sisal fibre content on mechanical characteristics of composites is the objective of research. Melt-mixing was used to make the composite, which was then laid out by hand layup method. The purpose of this research is to look at fibre oriented reinforced composite polymer nano composite materials that mix with hybrid composites such as JUTE, SISAL/EGG SHELL, and epoxy polymer in the ratio of sisal fibre 70% + jute 20% + Egg shell 10% and sisal fibre 60% + jute 20% + Egg shell 20% by volume. The mechanical characteristics were calculated by performing tests on the specimen’s tension, hardness, and flexural qualities in line with ASTM standards.