scholarly journals Mixed polymer and bioconjugate core/shell electrospun fibres for biphasic protein release

2021 ◽  
Author(s):  
Inchirah Adala ◽  
Jopeth Ramis ◽  
Cynthia Ntone Moussinga ◽  
Isabella Janowski ◽  
Mahetab H. Amer ◽  
...  
Keyword(s):  
Polyethylene Oxide ◽  
Protein Release ◽  
Core Material ◽  
Core Shell ◽  
Electrospun Scaffold ◽  
The Core ◽  
Bioactive Molecule

We report the fabrication of a coaxial electrospun scaffold with a bioactive molecule in the core and a protein conjugated at the surface. To construct the scaffold, we chose polyethylene oxide for the core material and a polycaprolactone/Jeffamine blend for the shell.

scholarly journals Iron Based Core-Shell Structures as Versatile Materials: Magnetic Support and Solid Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 72
Author(s):  
Christian Zambrzycki ◽  
Runbang Shao ◽  
Archismita Misra ◽  
Carsten Streb ◽  
Ulrich Herr ◽  
...  
Keyword(s):  
Water Purification ◽  
Functional Materials ◽  
Core Material ◽  
Solid Catalyst ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
The Core ◽  
Shell Nanostructures ◽  
Sio2 Shell ◽  
Iron Based

Core-shell materials are promising functional materials for fundamental research and industrial application, as their properties can be adapted for specific applications. In particular, particles featuring iron or iron oxide as core material are relevant since they combine magnetic and catalytic properties. The addition of an SiO2 shell around the core particles introduces additional design aspects, such as a pore structure and surface functionalization. Herein, we describe the synthesis and application of iron-based core-shell nanoparticles for two different fields of research that is heterogeneous catalysis and water purification. The iron-based core shell materials were characterized by transmission electron microscopy, as well as N2-physisorption, X-ray diffraction, and vibrating-sample magnetometer measurements in order to correlate their properties with the performance in the target applications. Investigations of these materials in CO2 hydrogenation and water purification show their versatility and applicability in different fields of research and application, after suitable individual functionalization of the core-shell precursor. For design and application of magnetically separable particles, the SiO2 shell is surface-functionalized with an ionic liquid in order to bind water pollutants selectively. The core requires no functionalization, as it provides suitable magnetic properties in the as-made state. For catalytic application in synthesis gas reactions, the SiO2-stabilized core nanoparticles are reductively functionalized to provide the catalytically active metallic iron sites. Therefore, Fe@SiO2 core-shell nanostructures are shown to provide platform materials for various fields of application, after a specific functionalization.

Nanoparticle@MoS2 Core–Shell Architecture: Role of the Core Material

2018 ◽  
Vol 30 (14) ◽  
pp. 4675-4682 ◽  
Author(s):  
Jennifer G. DiStefano ◽  
Yuan Li ◽  
Hee Joon Jung ◽  
Shiqiang Hao ◽  
Akshay A. Murthy ◽  
...  
Keyword(s):  
Core Material ◽  
Core Shell ◽  
The Core

scholarly journals Core–Shell Structured Phenolic Polymer@TiO2 Nanosphere with Enhanced Visible-Light Photocatalytic Efficiency

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 467
Author(s):  
Xiankui Xu ◽  
Lei Zhang ◽  
Shihua Zhang ◽  
Yanpeng Wang ◽  
Baoying Liu ◽  
...  
Keyword(s):  
Visible Light ◽  
Hydrothermal Reaction ◽  
Sol Gel ◽  
Core Material ◽  
Core Shell ◽  
Photocatalytic Efficiency ◽  
The Core ◽  
Phenolic Polymer ◽  
Colloid Nanoparticles ◽  
Tio2 Shell

Core–shell structured TiO2 is a promising solution to promote the photocatalytic effectiveness in visible light. Compared to metal or semiconductor materials, polymers are rarely used as the core materials for fabricating core–shell TiO2 materials. A novel core–shell structured polymer@TiO2 was developed by using phenolic polymer (PP) colloid nanoparticles as the core material. The PP nanoparticles were synthesized by an enzyme-catalyzed polymerization in water. A subsequent sol–gel and hydrothermal reaction was utilized to cover the TiO2 shell on the surfaces of PP particles. The thickness of the TiO2 shell was controlled by the amount of TiO2 precursor. The covalent connection between PP and TiO2 was established after the hydrothermal reaction. The core–shell structure allowed the absorption spectra of PP@TiO2 to extend to the visible-light region. Under visible-light irradiation, the core–shell nanosphere displayed enhanced photocatalytic efficiency for rhodamine B degradation and good recycle stability. The interfacial C–O–Ti bonds and the π-conjugated structures in the PP@TiO2 nanosphere played a key role in the quick transfer of the excited electrons between PP and TiO2, which greatly improved the photocatalytic efficiency in visible light.

scholarly journals Numerical Simulation of a Core–Shell Polymer Strand in Material Extrusion Additive Manufacturing

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 476
Author(s):  
Hamid Narei ◽  
Maryam Fatehifar ◽  
Ashley Howard Malt ◽  
John Bissell ◽  
Mohammad Souri ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Velocity Ratio ◽  
Diameter Ratio ◽  
Core Material ◽  
Operating Parameters ◽  
Core Shell ◽  
Material Extrusion ◽  
The Core ◽  
3D Printed ◽  
Core Polymer

Material extrusion additive manufacturing (ME-AM) techniques have been recently introduced for core–shell polymer manufacturing. Using ME-AM for core–shell manufacturing offers improved mechanical properties and dimensional accuracy over conventional 3D-printed polymer. Operating parameters play an important role in forming the overall quality of the 3D-printed manufactured products. Here we use numerical simulations within the framework of computation fluid dynamics (CFD) to identify the best combination of operating parameters for the 3D printing of a core–shell polymer strand. The objectives of these CFD simulations are to find strands with an ultimate volume fraction of core polymer. At the same time, complete encapsulations are obtained for the core polymer inside the shell one. In this model, the deposition flow is controlled by three dimensionless parameters: (i) the diameter ratio of core material to the nozzle, d/D; (ii) the normalised gap between the extruder and the build plate, t/D; (iii) the velocity ratio of the moving build plate to the average velocity inside the nozzle, V/U. Numerical results of the deposited strands’ cross-sections demonstrate the effects of controlling parameters on the encapsulation of the core material inside the shell and the shape and size of the strand. Overall we find that the best operating parameters are a diameter ratio of d/D=0.7, a normalised gap of t/D=1, and a velocity ratio of V/U=1.

scholarly journals Effect of Microcapsules of a Waterborne Core Material on the Properties of a Waterborne Primer Coating on a Wooden Surface

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 657 ◽  
Author(s):  
Xiaoxing Yan ◽  
Wenwen Peng
Keyword(s):  
Mass Fraction ◽  
Impact Resistance ◽  
Chromatic Aberration ◽  
Core Material ◽  
Core Shell ◽  
The Core ◽  
Mass Fractions ◽  
Wooden Surface ◽  
The Impact ◽  
Wooden Products

Microcapsules of a waterborne core material were prepared using a waterborne primer. The microcapsules of the waterborne core material were added to the waterborne primer to explore the effects of different core–shell ratios and mass fractions of the microcapsules on the property of the waterborne primer coating on the wooden surface. The results show that as the mass fraction of the microcapsules increased, the chromatic aberration increased by degrees, the glossiness decreased gradually, and the hardness increased by degrees, whilst—except for the coating with 0.50:1 microcapsules—the adhesion decreased gradually. When the mass fraction of the microcapsules increased, the impact resistance increased first and decreased later, or remained unchanged after reaching a certain value. When the mass fraction of the microcapsules increased, the elongation at the break increased first and decreased later. When the core–shell ratio was small and the mass fraction was between 5.0% and 15.0%, the coating had better liquid resistance. When the core–shell ratio was 0.67:1 and the mass fraction was 10.0%, the overall property of the coating on the Basswood was the best. The technology of microencapsulation provides a technical reference for the waterborne primer with self-repair qualities on the surface of wooden products.

Fabrication of thermo-regulating hexadecane-polyurethane core-shell composite nanofibrous mat as advanced technical layer: Effect of coaxial nozzle geometry

2016 ◽  
Vol 47 (6) ◽  
pp. 1134-1151 ◽  
Author(s):  
Massoumeh Rahimi ◽  
Javad Mokhtari
Keyword(s):  
Shell Structure ◽  
Core Material ◽  
Nozzle Geometry ◽  
Core Shell ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
The Core ◽  
Technical Textiles ◽  
Coaxial Nozzle ◽  
Core Shell Structure

Hexadecane-polyurethane core-shell nanoweb with thermo-regulating property has potential application in technical textiles such as protective clothing. However, there are challenges in preparation of hexadecane-polyurethane core-shell nanofibers due to non-conductivity of hexadecane as well as its low viscosity. The geometry of coaxial nozzle is one of the most important process parameters which plays vital role in the formation of core-shell structured materials such as hexadecane-polyurethane nanofibers. To study the effect of coaxial nozzle geometry on success level of forming core-shell structures, coaxial nozzles with different lengths of inner nozzles were applied. Core-shell structure with suitable phase separation was formed as confirmed by scanning electron microscopy. The presence of both materials (polyurethane and hexadecane) in the nanofibrous mats was established by attenuated total reflectance-Fourier transform infrared spectroscopy. Thermal properties of the nanowebs were studied using differential scanning calorimetry and thermal gravimetric analysis. The results showed that the coaxial nozzle geometry had a significant influence on producing the core-shell structured hexadecane-polyurethane nanofibers. After obtaining core-shell structure by optimizing coaxial nozzle geometry, the core content of nanofibers was increased from 13% to 33% by adding surfactant to the core material. These results showed that the core-shell structured nanofibers with high loading of hexadecane in their core could be obtained by modifying process and materials in co-electrospinning method.

scholarly journals Fabrication of Core-Shell PEI/pBMP2-PLGA Electrospun Scaffold for Gene Delivery to Periodontal Ligament Stem Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Qiao Xie ◽  
Lie-ni Jia ◽  
Hong-yu Xu ◽  
Xiang-gang Hu ◽  
Wei Wang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Gene Delivery ◽  
Periodontal Ligament ◽  
Transfection Efficiency ◽  
Coaxial Electrospinning ◽  
Core Shell ◽  
Electrospun Scaffold ◽  
Release Behavior ◽  
Periodontal Ligament Stem Cells ◽  
The Core

Bone tissue engineering is the most promising technology for enhancing bone regeneration. Scaffolds loaded with osteogenic factors improve the therapeutic effect. In this study, the bioactive PEI (polyethylenimine)/pBMP2- (bone morphogenetic protein-2 plasmid-) PLGA (poly(D, L-lactic-co-glycolic acid)) core-shell scaffolds were prepared using coaxial electrospinning for a controlled gene delivery to hPDLSCs (human periodontal ligament stem cells). The pBMP2 was encapsulated in the PEI phase as a core and PLGA was employed to control pBMP2 release as a shell. First, the scaffold characterization and mechanical properties were evaluated. Then the gene release behavior was analyzed. Our results showed that pBMP2 was released at high levels in the first few days, with a continuous release behavior in the next 28 days. At the same time, PEI/pBMP2 showed high transfection efficiency. Moreover, the core-shell electrospun scaffold showed BMP2 expression for a much longer time (more than 28 days) compared with the single axial electrospun scaffold, as evaluated by qRT-PCR and western blot after culturing with hPDLSCs. These results suggested that the core-shell PEI/pBMP2-PLGA scaffold fabricated by coaxial electrospinning had a good gene release behavior and showed a prolonged expression time with a high transfection efficiency.

scholarly journals In situ preparation and protein delivery of silicate–alginate composite microspheres with core-shell structure

2011 ◽  
Vol 8 (65) ◽  
pp. 1804-1814 ◽  
Author(s):  
Chengtie Wu ◽  
Wei Fan ◽  
Michael Gelinsky ◽  
Yin Xiao ◽  
Jiang Chang ◽  
...  
Keyword(s):  
Sustained Release ◽  
Shell Structure ◽  
Protein Delivery ◽  
Protein Release ◽  
Fickian Diffusion ◽  
Core Shell ◽  
Burst Release ◽  
The Core ◽  
Core Shell Structure

The efficient loading and sustained release of proteins from bioactive microspheres remain a significant challenge. In this study, we have developed bioactive microspheres which can be loaded with protein and then have a controlled rate of protein release into a surrounding medium. This was achieved by preparing a bioactive microsphere system with core-shell structure, combining a calcium silicate (CS) shell with an alginate (A) core by a one-step in situ method. The result was to improve the microspheres' protein adsorption and release, which yielded a highly bioactive material with potential uses in bone repair applications. The composition and the core-shell structure, as well as the formation mechanism of the obtained CS–A microspheres, were investigated by X-ray diffraction, optical microscopy, scanning electron microscopy, energy dispersive spectrometer dot and line-scanning analysis. The protein loading efficiency reached 75 per cent in CS–A microspheres with a core-shell structure by the in situ method. This is significantly higher than that of pure A or CS–A microspheres prepared by non- in situ method, which lack a core-shell structure. CS–A microspheres with a core-shell structure showed a significant decrease in the burst release of proteins, maintaining sustained release profile in phosphate-buffered saline (PBS) at both pH 7.4 and 4.3, compared with the controls. The protein release from CS–A microspheres is predominantly controlled by a Fickian diffusion mechanism. The CS–A microspheres with a core-shell structure were shown to have improved apatite-mineralization in simulated body fluids compared with the controls, most probably owing to the existence of bioactive CS shell on the surface of the microspheres. Our results indicate that the core-shell structure of CS–A microspheres play an important role in enhancing protein delivery and mineralization, which makes these composite materials promising candidates for application in bone tissue regeneration.

Magnetic Properties of Fe3O4/CoFe2O4 Composite Nanoparticles with Core/Shell Architecture

2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spinel Ferrite ◽  
Composite Nanoparticles ◽  
Core Shell ◽  
Cofe2o4 Nanoparticles ◽  
Core Diameter ◽  
The Core ◽  
Shell Particles ◽  
Interface Parameters ◽  
Shell Composite

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.

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