Core-shell Poly Research Articles

Significantly improved energy storage performance of polyetherimide-based dielectric composites via employing core-shell organic-semiconductor@BaTiO3 nanoparticles

With fast development of modern industries and electrical systems, polymer dielectrics are urgently demanded to have high discharged energy density (Ud) in elevated temperature. In this paper, novel core-shell poly [2-((3,6,7,10,11-pentakis (hexyloxy) triphenylene-2-yl) oxy) ethyl methacrylate] (PHT) coated barium titanate nanoparticles (BT) (denoted as PHT@BT) are prepared, and then incorporate into polyetherimide (PEI) matrix via solution blending method. Semi-conductive organic shell layer can not only promote the dispersion and compatibility of BT nanoparticles but also construct deep trap. As a result, 0.3 wt% PHT@BT/PEI composites achieve maximal Ud of 7.62 J cm−3 at 641 MV m−1 and room temperature, which is 1.93 times that of pure PEI film (3.93 J cm−3 at 461 MV m−1). Importantly, the Ud of 4.86 J cm−3 is obtained at 150 °C. This work provides superior interfacial modifier for inorganic nanofiller, which is of great significance for the fabrication of polymer-based nanocomposites with superior Ud.

Temporal resistance fluctuations during the initial filtration period of colloidal matter filtration

Membrane filtration processes with flux reversal for backwashing are employed to manage fouling during colloidal fluid treatment. This flux reversal accompanies filtration cycles where the total resistance increases over time. However, little is known about the initial phase of filtration. We focus on early filtration phase and present a microfluidic filtration system that allows precise observation of filtration resistances under constant flux or constant pressure operation for soft matter dead-end filtration with subsequent percolation of pure solvent. We identified temporal hydraulic resistance fluctuations during the start-up phase, which significantly differed from the steady-state condition. We focus on the experimental filtration of soft core–shell poly(N-isopropylacrylamide)-co-acrylic-acid microgels and observed a distinct peak in filter cake resistance with a subsequent reduction down to 50% of the initial peak resistance. To comprehend the phenomenon, we complement the experiments with temporal and spatial confocal microscopy studies linking cake compression and cake density gradients to its resistance. By comparing filtration, dialysis, and centrifugation as different microgel purification methods, we discover microgel shell degradation leading to detached polymer chains permeating in the downstream which causes the observed resistance reduction. This result demonstrates the permeation-induced degradation of macromolecular colloids during membrane filtration.

Strengthening and self‐healing of natural fiber composites via PLA core–shell nanofibers as healing agent carrier

AbstractThe resin‐rich region between the fiber laminates of a fiber‐reinforced composite is susceptible to matrix damage impeding the composite's integrity. Hence, this study intends to interlayer core–shell poly(lactic) acid (PLA) nanofibers between the flax fibers as a preventive and reactive mechanism to matrix damages in the resin‐rich area. The nanofibers prevent premature damage by suppressing or mitigating crack propagation and in the event of damage to the nanofibers, it reacts by releasing the encapsulated healing agent. Upon interlayering the flax fiber laminates with self‐healing core–shell nanofibers, the flexural modulus exhibited an increment of 31% whereas the short beam strength improved by 19%. Self‐healing traits of the composites were assessed by subjecting the composites to repeated flexural or short beam strength tests for several load cycles. Upon initial damage to the composites, the composites exhibited a full retention and improvement in mechanical properties. The self‐healing composites were also able to withstand more loading cycles than the conventional composite under repeated short‐beam strength tests. Under both configurations, the damaged self‐healing composites exhibited a residual strength greater than or equivalent to the ultimate strength of a pristine flax fiber composite.Highlights Fabrication of EP/flax self‐healing composites by PLA core–shell nanofibers. Interlayering healing nanofiber mats between flax fabrics in an FRP composite. Nanofiber interlayers exhibited a profound impact on the composite properties. Nano mats facilitate autonomous repair of internal defects within matrices. The self‐healing composites showed full retention and mechanical strength.

Synergistic effects of core–shell poly(ionic liquids)@ZIF-8 nanocomposites for enhancing additive-free CO2 conversion

The present study, for the first time, reports the fabrication of core–shell poly(ionic liquids)@ZIF-8 nanocomposites through a facile in-situ polymerization strategy. These composites exhibited exceptional structural characteristics including high specific surface areas and the integration of high-density Lewis acid/base and nucleophilic active sites. The structure–activity relationship, reusability, and versatility of the poly(ionic liquids)@ZIF-8 composites were investigated for the cycloaddition reaction between CO2 and epoxide. By optimizing the composites structures and their catalytic performance, PIL-Br@ZIF-8(2:1) was identified as an exciting catalyst that exhibits high activity and selectivity in the synthesis of various cyclic carbonates under mild or even atmospheric pressure or simulated flue gas conditions. Moreover, the catalyst demonstrated excellent structural stability while maintaining its catalytic activity throughout multiple usage cycles. By combining DFT calculations, we investigated the transition states and intermediate geometries of the cycloaddition reaction in different coordination microenvironments, thereby proposing a synergistic catalytic mechanism involving multiple active sites.

KARTOGENIN-ENCAPSULATED COAXIAL PGS/PCL-ALIGNED NANOFIBRES FOR ARTICULAR CARTILAGE REGENERATION

Electrospinning is an advantageous technique for cartilage tissue engineering (CTE) applications due to its ability to produce nanofibers recapitulating the size and alignment of the collagen fibers present within the articular cartilage superficial zone. Moreover, coaxial electrospinning allows the fabrication of core-shell fibers able to encapsulate and release bioactive molecules in a sustained manner. Kartogenin (KTG) is a small heterocyclic molecule, which was demonstrated to promote the chondrogenic differentiation of human bone marrow-derived mesenchymal stem/stromal cells(hBMSCs)[1].In this work, we developed and evaluated the biological performance of core-shell poly(glycerol sebacate)(PGS)/poly(caprolactone)(PCL) aligned nanofibers (core:PGS/shell:PCL) mimicking the native articular cartilage extracellular matrix(ECM) and able to promote the sustained release of the chondroinductive drug KTG[2].The produced coaxial aligned PGS/PCL scaffolds were characterized in terms of their structure and fiber diameter, chemical composition, thermal properties, mechanical performance under tensile testing and in vitro degradation kinetics, in comparison to monoaxial PCL aligned fibers and respective non-aligned controls. KTG was incorporated into the core PGS solution to generate core-shell PGS-KTG/PCL nanofibers and its release kinetics was studied by HPLC analysis. KTG-loaded electrospun aligned scaffolds capacity to promote hBMSCs chondrogenic differentiation was evaluated by assessing cell proliferation, typical cartilage-ECM production (sulfated glycosaminiglycans(sGAG)) and chondrogenic marker genes expression in comparison to non-loaded controls. All the scaffolds fabricated showed average fiber diameters within the nanometer-scale and the core-shell structure of the fibers was clearly confirmed by TEM. The coaxial PGS-KTG/PCL nanofibers evidenced a more sustained drug release over 21 days. Remarkably, in the absence of the chondrogenic cytokine TGF-β3, KTG-loaded nanofibers promoted significantly the proliferation and chondrogenic differentiation of hBMSCs, as suggested by the increased cell numbers, higher sGAG amounts and up-regulation of the chondrogenic genes COL2A1, Sox9, ACAN and PRG4 expression. Overall, our results highlight the potential of core-shell PGS-KTG/PCL aligned nanofibers for the development of novel MSC-based CTE strategies.Acknowledgements: The authors thank FCT for funding through the project InSilico4OCReg (PTDC/EME-SIS/0838/2021) and to institutions iBB (UID/BIO/04565/2020) and Associate Laboratory I4HB (LA/P/0140/2020).

Resveratrol-loaded co-axial electrospun poly(ε-caprolactone)/chitosan/polyvinyl alcohol membranes for promotion of cells osteogenesis and bone regeneration

The guided bone regeneration (GBR) membranes currently used in clinics are usually compromised by their limited osteogenic induction potential. In this study, we fabricate a core-shell poly(ε-caprolactone)/chitosan/polyvinyl alcohol (PCL/CS/PVA) GBR membrane with different amount of resveratrol (RSV), endowing the PCL/CS/PVA GBR membrane with superior osteogenic induction ability, which was not attained by the regular GBR membrane. The prepared GBR membranes were characterized by scanning electron microscopy, transmission electron microscopy, and CCK-8 and live-dead staining assays, and their osteogenic induction ability was evaluated using Col-I immunofluorescence staining, micro-computed tomography, haematoxylin and eosin staining and immunohistochemical staining. Results of the in vitro release experiment confirmed that the membranes exhibited a continuous RSV release profile for 15 days. Furthermore, the cumulative releasing of RSV was increased from 39.68 ± 2.09 μg to 65.8 ± 2.91 μg with increasing contents of RSV from 0.1 % to 0.5 % (w/v) in the core layer of GBR membranes. In particular, the PCL/CS/PVA GBR membrane loading with 0.5 % RSV most efficiently release RSV in a sustained and controlled manner, which significantly induced osteogenic differentiation of pre-osteoblasts in vitro and bone regeneration in vivo. Based on the in vivo histological findings, newly formed bone tissues with 82.46 ± 9.86 % BV/TV and 0.70 ± 0.07gcm−3 BMD were generated in the defect sites treated by the GBR membrane loaded with 0.5 % RSV, which were the largest values among those for all three groups after 12 weeks of post implantation. Overall, the PCL/CS/PVA GBR membrane loaded with 0.5 % RSV has significant potential for bone regeneration.

Sub-50 nm core-shell nanoparticles with the pH-responsive squeezing release effect for targeting therapy of hepatocellular carcinoma.

The development of drug delivery systems with high drug loading capacity, low leakage at physiological pH, and rapid release at the lesion sites remains an ongoing challenge. In this work, core-shell poly(6-O-methacryloyl-D-galactose)@poly(tert-butyl methacrylate) (PMADGal@PtBMA) nanoparticles (NPs) of sub-50 nm are facilely synthesized by reversible addition-fragmentation chain transfer (RAFT) soap-free emulsion polymerization with the assistance of 12-crown-4. A hydrophilic poly(methacrylic acid) (PMAA) core can then be revealed after deprotection of the tert-butyl groups, which is negatively charged and can adsorb nearly 100% of incubated doxorubicin (DOX) from a solution at pH 7.4. The physical shrinkage of PMAA chains below pH 6.0 endows the core with the squeezing effect, therefore realizing rapid drug release. It is demonstrated that the DOX release rate of PMADGal@PMAA NPs at pH 5 was 4 times that at pH 7.4. Cellular uptake experiments confirm the high targeting ability of the galactose modified PMADGal shell to human hepatocellular carcinoma (HepG2) cells. The fluorescence intensity of DOX in HepG2 cells is 4.86 times that of HeLa cells after 3 h incubation. Moreover, 20% cross-linked NPs show the highest uptake efficiency by HepG2 cells due to their moderate surface charge, size and hardness. In summary, both the core and the shell of PMADGal@PMAA NPs promise the rapid site-specific release of DOX in HepG2 cells. This work provides a facile and an effective strategy to synthesize core-shell NPs for hepatocellular carcinoma targeting therapy.

Preparation and Cavilation Erosion Resistance of High Strength Nanocoating Cylinder Liner

Using ammonium persulfate as an oxidant and nano-silica as dispersing medium,o-toluidine was oxidized to form a core-shell structure poly (o-toluidine)/nano-SiO2 particle. Investigation of particle yield by ICP-AES method, the adhesion method was used to study the adhesion between coating and cylinder liner. The cavitation resistance of the coating cylinder was studied by the vibration gas cavitation method. The results showed that poly(o-toluidine) was uniformly coated around the nano-silica particles to which forms stable poly (o-toluidine)/nano-SiO2 with core-shell structure, when m(SiO2):m(POT)=1:8，n((NH4)2S2O3):n(POT)=1:1,and the temperature was controlled from 10 to 15°C, the composite poly(o-toluidine)/nano-SiO2 particles were prepared and the yield reached 85%. Composite poly(o-toluidine)/nano-SiO2 particles as a functional component and epoxy resin as a film-forming agent were used to prepare composite poly(o-toluidine)/nano-SiO2/epoxy resin coated cylinder liner with good cavitation resistance, t100=885min.

Synthesis of core-shell bottlebrush polymers of poly(polycaprolactone-b-polyethylene glycol) via ring-opening metathesis polymerization

This research was focused on the synthesis of core-shell bottlebrush polymer poly(PCL-b-PEG) (PCL: polycaprolactone; PEG: polyethylene glycol) through a combination of ring-opening polymerization (ROP) and ring-opening metathesis polymerization (ROMP). Three main steps were involved in this synthesis: firstly, the ROP of ε-caprolactone was conducted to form an amphiphilic linear polymer PEG-b-PCL in presence of methoxypolyethylene glycols and Sn(Oct)2; secondly, macromonomers with norbornenyl-functionalization were synthesized by the esterification of the hydroxyl-terminated PEG-b-PCL with 5-norbornene-2-carboxylic acid; thirdly, the synthesized macromonomers were further polymerized by ROMP in presence of Grubbs second-generation catalyst to form a core-shell bottlebrush structured polymer. The effects of the reaction time, concentrations of small-molecule monomers, amount of catalyst and the molecular weights of macromonomers on the performance of the ROMP of the macromonomers were investigated in detail. 1H NMR and GPC analyses confirmed the structures of the resulting polymers. DSC, XRD, TGA were used to characterize the properties of PEG-b-PCL and poly(PCL-b-PEG). Compared with the linear block polymers PEG-b-PCL, the resulting polymers with core-shell bottlebrush structures have a more regular chain arrangement and better thermal stability.

Programmed core-shell electrospun nanofibers to sequentially regulate osteogenesis-osteoclastogenesis balance for promoting immediate implant osseointegration

The biology of immediate post-extraction implant osseointegration is mediated by a coordinated cascade of osteoblast-osteoclast interactions. The aim of this study was to develop a dual-delivery system that allowed sequential release of substance P (SP) to promote bone regeneration and alendronate (ALN) to reduce bone resorption, which will improve the implant osseointegration. We used coaxial electrospinning to fabricate the core-shell poly lactic-co-glycolic acid (PLGA)/gelatin nanofibers, which consists of SP in the shell and ALN in the core. This programmed delivery system was shown to release SP and ALN sequentially to match the spatio-temporal specificity of bone healing. The migration assay demonstrated that the SP-ALN dual-delivery system increased bone marrow mesenchymal stem cells (BMSCs) transmigration. Besides, the expression of osteogenic/osteoclastic markers, Alizarin Red staining, tartrate-resistant acid phosphatase (TRAP) staining, F-actin staining and bone resorption experiment showed that the dual-delivery system can render a microenvironment favorable for osteogenic differentiation and adverse to osteoclastogenesis. Using a rat immediate implant model, we validated the promoted osteogenic property and osseointegration around the implants of SP-ALN dual-delivery system by micro-computed tomography (micro-CT) and histological analysis. These findings suggest that the dual-delivery system with time-controlled release of SP and ALN by core-shell nanofibers provides a promising strategy to facilitate immediate implant osseointegration through favorable osteogenesis. Statement of significanceImmediate implant placement is potentially challenged by the difficulties in achieving primary implant stability and early osteogenesis. Initial period of osteointegration is regulated by osteoblastic/osteoclastic cells resulting in a coordinated healing process. To have an efficient bone regeneration, the coaxial electrospinning was used to fabricate a programmed dual-delivery system. The SP released rapidly and favored for BMSCs migration and osteogenic differentiation, while the sustained release of ALN can reduce the bone resorption. The rat immediate implant model indicated that the SP-ALN dual-delivery system could present the promoted peri‑implant osteogenic property and osseointegration through modulating the osteogenesis-osteoclastogenesis balance. This work highlights the sequential dual delivery of SP and ALN has a promising potential of achieving enhanced osseointegration for immediate implant placement.

3D core-shell poly(aniline-co-pyrrole)/reduced graphene oxide composite for supercapacitor performance

Due to favourable pseudo-capacitive performance, the polyaniline and polypyrrole are highly potential candidates for supercapacitor applications. In this study, core-shell poly(aniline-co-pyrrole) is prepared by in-situ chemical polymerization of pyrrole in the presence of polyaniline nanofibers. Poly(aniline-co-pyrrole) is mixed with the suspension of graphene oxide to prepare three-dimensional core-shell poly(aniline-co-pyrrole)/reduced graphene oxide composite using hydrothermal method. The as-synthesized samples are characterized by X-ray diffraction, Scanning electronic microscopy, Transmission electron microscope, FTIR spectroscopy, Raman spectroscopy and electrochemical measurements for the morphology, structure and supercapacitor performance of the composite. Results show that poly(aniline-co-pyrrole) is inlaid into the three-dimensional reduced graphene oxide. Poly(aniline-co-pyrrole)/reduced graphene oxide exhibits superior supercapacitor performance among the composites, benefiting from its unique composite structures, innate electrochemical properties and the synergistic effect of three-dimensional reduced graphene oxide and poly(aniline-co-pyrrole). The maximum specific capacitance of three-dimensional core-shell poly(aniline-co-pyrrole)/reduced graphene oxide composite prepared at a mass ratio of graphene oxide and poly(aniline-co-pyrrole) of 0.9:1 is 684.5 F·g−1 at a current density of 1 A·g−1. Even at a current density of 20 A·g−1, the specific capacitance still reaches 417 F·g−1. The capacitance retention of three-dimensional core-shell poly(aniline-co-pyrrole)/reduced graphene oxide electrode is 88% after 1000 charge and discharge cycles, showing excellent supercapacitor performance.

Core-Shell Poly(l-lactic acid)-Hyaluronic Acid Nanofibers for Cell Culture and Pelvic Ligament Tissue Engineering.

Pelvic organ prolapse (POP) has become one of the most common serious diseases affecting parous women. Weakening of pelvic ligaments plays an essential role in the pathophysiology of POP. Currently, synthetic materials are widely applied for pelvic reconstructive surgery. However, synthetic nondegradable meshes for POP therapy cannot meet the clinical requirements due to its poor biocompatibility. Herein, we fabricated electrospun core-shell nanofibers of poly(l-lactic acid)-hyaluronic acid (PLLA/HA). After that, we combined them with mouse bone marrow-derived mesenchymal stem cells (mBMSCs) to assess the cellular response and pelvic ligament tissue engineering in vitro. The cellular responses on the composite nanofibers showed that the core-shell structure nanofibers displayed with excellent biocompatibility and enhanced cellular activity without cytotoxicity. Moreover, compared with PLLA nanofibers seeded with mBMSCs, PLLA/HA nanofibers exhibited more cellular function, as revealed by the quantitative real-time polymerase chain reaction (RT-qPCR) for pelvic ligament-related gene markers including Col1a1, Col1a3 and Tnc. These features suggested that this novel core-shell nanofiber is promising in stem cell-based tissue engineering for pelvic reconstruction.

Constructing a passive targeting and long retention therapeutic nanoplatform based on water-soluble, non-toxic and highly-stable core-shell poly(amino acid) nanocomplexes.

Drug delivery nanoplatforms have been applied in bioimaging, medical diagnosis, drug delivery and medical therapy. However, insolubility, toxicity, instability, nonspecific targeting and short retention of many hydrophobic drugs limit their extensive applications. Herein, we have constructed a passive targeting and long retention therapeutic nanoplatform of core-shell gefitinib/poly (ethylene glycol)-polytyrosine nanocomplexes (Gef-PY NCs). The Gef-PY NCs have good water-solubility, non-toxicity (correspond to 1/10 dosage of effective gefitinib (hydrochloride) (Gef·HCl) (normal drug administration and slow-release) and high stability (120 days, 80% drug retention at 4 or 25 °C). The core-shell Gef-PY NCs present unexpected kidney targeting and drug slow-release capacity (ca. 72 h). The good water-solubility, non-toxicity and high stability of Gef-PY NCs effectively solve the bottleneck question that Gef-based therapy could be used only in intraperitoneal injection due to its insolubility and severe toxicity. Such excellent properties (e.g., water-solubility, non-toxicity, high stability, kidney targeting and long retention) of Gef-PY NCs create their prominent anti-fibrosis capabilities, such as decreasing approximately 40% tubulointerstitial fibrosis area and 68% expression of collagen I within 7 days. This therapeutic efficacy is well-matched with that of 10 times the dosage of toxic Gef·HCl. It is very hopeful that Gef-PY NCs could realize clinical applications and such a strategy offers an effective route to design high-efficiency treatments for kidney- and tumor-related diseases.

Electrical conductivity of poly(methyl methacrylate) nanocomposites containing interconnected carbon nanohybrid network based on Pickering emulsion strategy

ABSTRACT The formation of three-dimensional (3D) interconnected carbon network throughout insulative polymer matrix is advantageous to elaborating electrically conductive nanocomposites. Herein, oil-in-water (O/W) Pickering emulsion stabilized by carbon nanohybrids assembled with reduced graphene oxide (RGO) and carbon nanotubes (CNTs) was utilized as a template to achieve core-shell structured poly(methyl methacrylate) (PMMA) microsphere. The effect of synthesis time on the amphiphilicity of carbon nanohybrid stabilizer is studied. Investigations on the as-prepared Pickering emulsion and the electrical conductivity of the derived carbon nanohybrid composites were directed with respect to the concentration and formulation of carbon nanohybrid stabilizer, respectively. Considering a balance between electrical and mechanical properties, 0.74 wt% of carbon nanohybrid stabilizer was used to form O/W Pickering emulsion, which was responsible for the electrical conductivity of 4 × 10−8 S m−1 for the resulting RGO/CNTs/PMMA nanocomposites. The processing-structure-property relationship of carbon nanocomposites based on O/W Pickering emulsion strategy is further demonstrated in scanning electron microscopy (SEM) observation and thermo-mechanical analysis. The processing and functional synergies between GO and CNTs are identified to efficiently construct interconnected electrically conductive pathway in polymer matrix.

4-Nitrophenol imprinted core-shell poly(N-isopropylacrylamide-acrylic acid)/poly(acrylic acid) microgels loaded with cadmium nanoparticles: A novel catalyst

4-nitrophenol imprinted poly(N-isopropylacrylamide-acrylic)/poly(acrylic acid) [p(NIPAM-AAc)/p(AAc)] microgels are synthesized by precipitation polymerization. 1 and 95 mol % of AAc is incorporated in core and shell of synthesized microgels respectively, so that shell can be swollen up to large extent instead of core part. Cd nanoparticles are synthesized within core using in situ reduction. Size of Cd nanoparticles and structure of microgels are analyzed by STEM, FTIR and UV–Vis spectroscopy. Series of 4-NP and its derivatives (nitroarenes and azo dyes) are reduced by using synthesized microgel as catalyst in aqueous medium. Significant difference in apparent rate constant (kapp), percentage reduction and reduction time among 4-NP and its derivatives is observed. This shows that 4-NP imprinting has affected the sieve of microgels and orientation of carboxyl groups (COOH) of AAc. Effect of solvents on catalytic reduction of 3-NP is also studied using synthesized microgel as catalyst. Significant difference in kapp, percentage reduction and reduction time of 3-NP in different solvents is also observed. 95% AAc in imprinted shell is observed as capable catalyst for reduction of 4-NP template and its derivatives. Synthesized microgel has multiple features: 4-NP imprinting, core-shell structure and 95% AAc in shell. All of these features are helped in the catalytic reduction of nitro compounds. The compounds similar to 4-NP are reduced more as compared to other compounds due to 4-NP imprinting. This shows that synthesized MIP is more effective for reduction of compounds similar to 4-NP. High mol percentage of AAc monomer within shell is facilitated the diffusion of substrates towards nanoparticles embedded in core. Possible product formation of nitroarenes and azo dyes in the presence of microgel was reported. Effect of different solvents on catalytic reduction of 3-NP is also observed.

Evaluation of core–shell poly(vinylidene fluoride)-grafted-Barium titanate (PVDF-g-BaTiO3) nanocomposites as a cathode binder in batteries

Poly(vinylidene fluoride)-grafted-Barium titanate (PVDF-g-BaTiO3) nanocomposites were used as binders to prepare cathode material containing 70 wt% of active material (LiMn2O4), 18 wt% of conducting agent (carbon black) and 12 wt% of binder (either commercially available PVDF, modified PVDF such as PVDF-g-BaTiO3, or both). A calendering process was used in order to obtain homogenous films and a better dispersity of nanoparticles. First, the electrochemical behavior of the modified PVDF was explored in the absence of the active material and did not revealed any electrochemical activity. Then, after adding the active material into the formulation (4–12 wt%), cells made with commercially available PVDF displayed similar cycling performances as the one achieved from 4 wt% of modified PVDF. For example, at 1C, the initial discharge capacities were 146, 140 and 130 mA h g−1 for films made by 0, 4 and 8% of modified PVDF, respectively. Moreover, with the increase of charge discharge rate to 10C, the capacity can be approximately recovered when the current density returned to 1C for all the samples, revealing a good reversibility of the structure. On the other hand, calendering procedure enables to obtain a uniform structure demonstrated by reproducible tests as compared to those achieved from non-calendered films. Moreover, the calendering process showed an enhancement in cycling performances. For instance, the initial discharge capacity at 1C was 124 and 108 mA h g−1 and decreased to 82 and 2 mA h g−1 at 10C for non-calendered and calendered sample made with commercial PVDF, respectively.

Core-Shell poly-(D,l-Lactide-co-Glycolide)-chitosan Nanospheres with simvastatin-doxycycline for periodontal and osseous repair

This study aimed to evaluated the potential of core-shell poly(D,l-lactide-co-glycolide)-chitosan (PLGA-chitosan) nanospheres encapsulating simvastatin (SIM) and doxycycline (DOX) for promoting periodontal and large-sized osseous defects. SIM, and/or DOX were encapsulated in PLGA-chitosan nanospheres using double emulsion technique and were delivered to sites of experimental periodontitis and large-sized mandibular osseous defects of rats for 1–4 weeks. The resultant nanospheres were ~ 200 nm diameter with distinct core-shell structure and released SIM and DOX sustainably for 28 days. DOX and SIM-DOX nanospheres significantly inhibited P. gingivalis and S. sanguinis. In experimental periodontitis sites, SIM-DOX nanospheres significantly down-regulated IL-1b and MMP-8 and significantly reduced bone loss. In mandibular osseous defects, VEGF was up-regulated, and osteogenesis was significantly augmented with SIM nanospheres treatment. In conclusion, core-shell PLGA-chitosan nanospheres released SIM and DOX sustainably. SIM-DOX and SIM nanospheres could be considered to promote the repair of infected periodontal sites and non-infected osseous defects respectively.

Improved energy density in core–shell poly(dopamine) coated barium titanate/poly(fluorovinylidene-co-trifluoroethylene) nanocomposite with interfacial polarization

Polymer dielectric nanocomposite with high dielectric property and large power density is one of the most promising candidates in wearable electronics and polymer film capacitors due to its lightweight and flexibility as well as processability. In order to improve energy density and charge-discharge efficiency of film capacitor, in which the interfacial compatibility between the fillers and matrix often plays a key role in the enhancement of the electrical energy capability. In this work, the core-shell architecture with poly(dopamine) (PDA) encapsulated on the barium titanate particles (D-BT) via condensation reaction was tailored to improve the compatibility in polymer nanocomposite. The high dielectric constant of 46.4 with the low loss as 0.07 at 100 Hz is obtained in 15 wt% D-BT/P(VDF-TrFE) nanocomposite due to the interfacial compatibility resulting from the strong hydrogen bonds between PDA segments and macromolecular chains. The recovered energy density of 5 wt% nanocomposite film reaches 3.2 J/cm3 with the charge-discharge efficiency of 68%, which is attributed to the large content of electroactive phase and interfacial polarization. This work provides a simple technique to improve electrical energy capability, and sheds a light on the enhancement of interfacial mechanism in the polymer nanocomposite for film capacitor.

Semi-elastic core-shell nanoparticles enhanced the oral bioavailability of peptide drugs

The rigidity of nanoparticles was newly reported to influence their oral delivery. Semi-elastic nanoparticles can enhance the penetration in mucus and uptake by epithelial cells. However, it is still challenging and unclear that the semi-elastic core-shell nanoparticles can enhance the oral bioavailability of peptide drugs. This study was for the first time to validate the semi-elastic core-shell poly(lactic-co-glycolic acid) (PLGA)-lipid nanoparticles (LNPs) as the carrier of the oral peptide drug. The antihypertensive peptide Val-Leu-Pro-Val-Pro (VP5) loaded LNPs (VP5-LNPs) were prepared by a modified thin-film ultrasonic dispersion method. Uptake experiment was performed in Caco-2 and HT-29 cells and monitored by high content screening (HCS) and flow cytometric (FCM). Pharmacokinetics of VP5-LNPs was carried out in Sprague-Dawley (SD) rats and analyzed by DAS 2.0. The optimal VP5-LNPs had an average particle size of 247.3±3.8nm, zeta potential of −6.57±0.45mV and excellent entrapment efficiency (EE) of 89.88%±1.23%. Transmission electron microscope (TEM) and Differential scanning calorimeter (DSC) further confirmed the core-shell structure. VP5-LNPs could increase the cellular uptake in vitro and have a 2.55-fold increase in AUC0-72h, indicating a great promotion of the oral bioavailability. The semi-elastic LNPs remarkably improved the oral availability of peptide and could be a promising oral peptide delivery system for peptide drugs in the future.

Core-Shell Polymer-Based Nanoparticles Deliver miR-155-5p to Endothelial Cells

Heart failure occurs in over 30% of the worldwide population and most commonly originates from cardiovascular diseases such as myocardial infarction. microRNAs (miRNAs) target and silence specific mRNAs, thereby regulating gene expression. Because the endogenous miR-155-5p has been ascribed to vasculoprotection, loading it onto positively charged, core-shell poly(isobutylcyanoacrylate) (PIBCA)-polysaccharide nanoparticles (NPs) was attempted. NPs showed a decrease (p < 0.0001) in surface electrical charge (ζ potential), with negligible changes in size or shape when loaded with the anionic miR-155-5p. Presence of miR-155-5p in loaded NPs was further quantified. Cytocompatibility up to 100 μg/mL of NPs for 2 days with human coronary artery endothelial cells (hCAECs) was documented. NPs were able to enter hCAECs and were localized in the endoplasmic reticulum (ER). Expression of miR-155-5p was increased within the cells by 75-fold after 4 hours of incubation (p < 0.05) and was still noticeable at day 2. Differences between loaded NP-cultured cells and free miRNA, at days 1 (p < 0.05) and 2 (p < 0.001) suggest the ability of prolonged load release in physiological conditions. Expression of miR-155-5p downstream target BACH1 was decreased in the cells by 4-fold after 1 day of incubation (p < 0.05). This study is a first proof of concept that miR-155-5p can be loaded onto NPs and remain intact and biologically active in endothelial cells (ECs). These nanosystems could potentially increase an endogenous cytoprotective response and decrease damage within infarcted hearts.