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The past two decades have witnessed the enormous success and progress of electrospinning, as well as its broad and useful applications in pharmaceutics as a laboratory pharmaceutical nanotechnology. Everything in the past is a preface, in which the large screen opens for electrospinning and electrospun nanofibers (particularly those multiple-fluid electrospinning processes and the related multiple-chamber nanostructures) to stride into a new stage and the real commercial applications. In this commentary, four hot regions are identified for the further progress of the applications of electrospinning in pharmaceutics, in which electrospinning and its products can provide more and better services to the development of pharmaceutics. [ABSTRACT FROM AUTHOR]

It is anticipated that the combination of biomolecules and electrospinning will provide potential useful solutions for these issues, and thus strengthen the drug delivery applications of biomolecule-based nano products. Drug delivery often involves the reasonable selection of drug carriers and additives, which are expected to safely escort the drug molecules to the lesion site (the right section of Figure 1). In general, DDSs composed of electrospun biomolecule-based nanofibers can be those: (1) containing pharmaceutical active biomolecules (both small biomolecules and biomacromolecules) as the guest ingredients, which are very common in developing medicated nanofibers; (2) containing inert biomacromolecules as the matrices to load drugs; (3) containing inert small molecules as drug carriers or additives in electrospun nanofibers for a better drug delivery effect. Drug delivery, mainly a professional term in pharmaceutics, is a field of interdisciplinary intersection and integration [[1], [3]]. [Extracted from the article]

Students' behaviors have a close relationship with their learning efficiencies, particularly about professional knowledge. Different types of behaviors should have different influences. Disclosing the special relationship between undergraduate students' conscious safety behaviors in their laboratory experiments with their learning efficiencies is important for fostering them into professional talents. In this study, a course entitled "Advanced Methods of Materials Characterization" was arranged to contain three sections: theoretical learning in the classroom, eight characterization experiments in the laboratory in sequence, and self-training to apply the knowledge. In the final examination, eighteen percent was allocated to the examination questions about safety issues. The students' scores for this section were associated with their total roll scores. Two quantitative relationships are disclosed. One is between the students' final examination score (y) and their subjective consciousness of safety behaviors (x) in their laboratory experiments, as y = 5.56 + 4.83 x (R = 0.9192). The other is between their grade point average (y) and safety behavior evaluation (x) as y = 0.51 + 0.15 x (R = 0.7296). Undergraduate students' behaviors in scientific laboratories need to be verified to have a close and positive relationship with their professional knowledge learning efficiencies. This offers a hint that improving students' safety behaviors and enhancing their subjective safety awareness are conducive to improving their learning efficiency for professional knowledge. [ABSTRACT FROM AUTHOR]

Side-by-side electrospinning is a powerful but challenging technology that can be used to prepare Janus nanofibers for various applications. In this work, cellulose acetate (CA) and polycaprolactone (PCL) were used as polymer carriers for silver nanoparticles (Ag NPs) and lavender oil (LO), respectively, processing these into two-compartment Janus fibers. A bespoke spinneret was used to facilitate the process and prevent the separation of the working fluids. The process of side-by-side electrospinning was recorded with a digital camera, and the morphology and internal structure of the products were characterized by electron microscopy. Clear two-compartment fibers are seen. X-ray diffraction patterns demonstrate silver nanoparticles have been successfully loaded on the CA side, and infrared spectroscopy indicates LO is dispersed on the PCL side. Wetting ability and antibacterial properties of the fibers suggested that PCL-LO//CA-Ag NPs formulation had strong antibacterial activity, performing better than fibers containing only one active component. The PCL-LO//CA-Ag NPs had a 20.08 ± 0.63 mm inhibition zone for E. coli and 19.75 ± 0.96 mm for S. aureus. All the fibers had water contact angels all around 120°, and hence, have suitable hydrophobicity to prevent water ingress into a wound site. Overall, the materials prepared in this work have considerable promise for wound healing applications. [ABSTRACT FROM AUTHOR]

Both finding new types of biomolecules, and a reasonable selection of the starting biomolecules for preparing biomolecule-based functional materials, are important. A most recent trend for constructing new biomolecules of biomolecule-based composites is to the combination of organic and inorganic elements. The present issue "Biomolecule-based composites, hybrids and nanostructures for biomedical applications" is just centered around these elements and thus seven excellent publications have been selected for publication. Biomolecules, as molecules which have a bio-source or a certain bioapplication, are at present quickening the marching speed for benefiting people's life and social progress. [Extracted from the article]

Graphical abstract Highlights • A strategy was shown for enhancing the dissolution of poorly water-soluble drug. • A modified coaxial electrospraying was developed. • Unsolidifiable solution was explored as shell working fluid. • Extremely thin composite functional shell was built on a blank core. • Immediate release of helicid due to nanoeffects provided by a thin surface layer. Abstract In this paper, a modified coaxial electrospraying process was explored for the generation of novel nanoscale composite materials. A solution comprising 5% (w/v) of the model drug helicid and 10% (w/v) polyvinylpyrrolidone (PVP) K 10 in a mixture of N,N-dimethylacetamide and ethanol (4:6, v:v) was employed as the shell working liquid. This could not be processed into a solid product when processed by single-fluid electrospraying. However, when undertaking co-axial electrospraying with a core shellac solution (40% w/v in ethanol) solid particles were obtained. An extremely thin nanocoating layer of drug-polymer composite with an estimated thickness of 7 nm was deposited on a shellac core. X-ray diffraction and infrared spectroscopy demonstrated that the drug was converted into an amorphous nanocomposite with the PVP in the shell layer, losing its original crystalline state. In vitro dissolution tests revealed that all the helicid loading could be released within one minute, suggesting the particles have potential applications to deliver very rapid therapeutic effects. Mechanisms are proposed underlying the formation and functional performance of the materials. [ABSTRACT FROM AUTHOR]

Abstract The development of oral dosage forms for poorly water-soluble active pharmaceutical ingredients (APIs) is a persistent challenge. A range of methods has been explored to address this issue, and amorphous solid dispersions (ASDs) have received increasing attention. ASDs are typically prepared by starting with a liquid precursor (a solution or melt) and applying energy for solidification. Many techniques can be used, with the emergence of electrospinning as a potent option in recent years. This method uses electrical energy to induce changes from liquid to solid. Through the direct applications of electrical energy, electrospinning can generate nanofiber-based ASDs from drug-loaded solutions, melts and melt-solutions. The technique can also be combined with other approaches using the application of mechanical, thermal or other energy sources. Electrospinning has numerous advantages over other approaches to produce ASDs. These advantages include extremely rapid drying speeds, ease of implentation, compatibility with a wide range of active ingredients (including those which are thermally labile), and the generation of products with large surface areas and high porosity. Furthermore, this technique exhibits the potential to create so-called 'fifth-generation' ASDs with nanostructured architectures, such as core/shell or Janus systems and their combinations. These advanced systems can improve dissolution behaviour and provide programmable drug release profiles. Additionally, the fiber components and their spatial distributions can be precisely controlled. Electrospun fiber-based ASDs can maintain an incorporated active ingredient in the amorphous physical form for prolonged periods of time because of their homogeneous drug distribution within the polymer matrix (typically they comprise solid solutions), and ability to inhibit molecular motion. These ASDs can be utilised to generate oral dosage forms for poorly water-soluble drugs, resulting in linear or multiple-phase release of one or more APIs. Electrospun ASDs can also be exploited as templates for manipulating molecular self-assembly, offering a bridge between ASDs and other types of dosage forms. This review addresses the development, advantages and pharmaceutical applications of electrospinning for producing polymeric ASDs. Material preparation and analysis procedures are considered. The mechanisms through which performance has been improved are also discussed. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Hypromellose (HPMC)-based hydrophilic composites (HCs) used for rapid dissolution of ferulic acid (FA) were investigated. Electrospun and casting HCs were prepared from a solution containing HPMC, FA, and polyethylene glycol. Ethanol was used as sheath fluid during coaxial processes, and the effects of its flow rates on the Taylor cone and straight fluid jet were investigated. The morphology, component state, hydrophilicity, and drug dissolution rate of the HCs were characterized. Results demonstrated that all HCs were amorphous materials, and their components were compatible. However, the dissolution rate of electrospun HCs was 10 times faster than that of casting HCs. The smaller the diameters of electrospun HCs were, the better their performances were. The mechanism of electrospun HCs was suggested. By utilizing modified coaxial electrospinning and combinations of drug carriers, new types of HPMC-based HCs can provide an alternative approach for the effective delivery of poorly water-soluble drugs. [ABSTRACT FROM AUTHOR]

A structured spinneret comprising two acentric needles nested into a third metal capillary was developed to conduct three-fluid electrospinning processes. With an exterior solvent surrounding two core fluids arranged side-by-side, high quality polyvinylpyrrolidone/shellac Janus nanofibers could be prepared, which was not possible using a standard side-by-side spinneret without this innovation. [ABSTRACT FROM AUTHOR]

A family of medicated Janus fibers that provides highly tunable biphasic drug release was fabricated using a side-by-side electrospinning process employing a Teflon-coated parallel spinneret. The coated spinneret facilitated the formation of a Janus Taylor cone and in turn high quality integrated Janus structures, which could not be reliably obtained without the Teflon coating. The fibers prepared had one side consisting of polyvinylpyrrolidone (PVP) K60 and ketoprofen, and the other of ethyl cellulose (EC) and ketoprofen. To modulate and tune drug release, PVP K10 was doped into the EC side in some cases. The fibers were linear and had flat morphologies with an indent in the center. They provide biphasic drug release, with the PVP K60 side dissolving very rapidly to deliver a loading dose of the active ingredient, and the EC side resulting in sustained release of the remaining ketoprofen. The addition of PVP K10 to the EC side was able to accelerate the second stage of release; variation in the dopant amount permitted the release rate and extent this phase to be precisely tuned. These results offer the potential to rationally design systems with highly controllable drug release profiles, which can complement natural biological rhythms and deliver maximum therapeutic effects. [ABSTRACT FROM AUTHOR]

A series of 5-fluorouracil (5-FU) loaded core/shell electrospun fibers is reported. The fibers have shells made of Eudragit S100 (ES-100), and drug-loaded cores comprising poly(vinylpyrrolidone), ethyl cellulose, ES-100, or drug alone. Monolithic 5-FU loaded ES-100 fibers were also prepared for comparison. Electron microscopy showed all the fibers to have smooth cylindrical shapes, and clear core–shell structures were visible for all samples except the monolithic fibers. 5-FU was present in the amorphous physical form in all the materials prepared. Dissolution studies showed that the ES-100 shell was not able to prevent drug release at pH 1.0, even though the polymer is completely insoluble at this pH: around 30–80% of the maximum drug release was reached after 2 h immersion at pH 1.0. These observations are ascribed to the low molecular weight of 5-FU permitting it to diffuse through pores in the ES-100 coating, and the relatively high acid solubility of the drug providing a thermodynamic impetus for this to happen. In addition, the fibers were observed to be broken or merged following 2 h at pH 1.0, giving additional escape routes for the 5-FU. [ABSTRACT FROM AUTHOR]

Medicated shellac nanofibers providing colon-specific sustained release were fabricated using coaxial electrospinning. A solution of 7.5 g shellac and 1.5 g of ferulic acid (FA) in 10 mL ethanol was used as the core fluid, and a mixture of ethanol and N , N -dimethylformamide (8/10 v/v) as the shell. The presence of the shell fluid was required to prevent frequent clogging of the spinneret. The diameters of the fibers ( D ) can be manipulated by varying the ratio of shell to core flow rates ( F ), according to the equation D = 0.52 F −0.19 . Scanning electron microscopy images revealed that fibers prepared with F values of 0.1 and 0.25 had linear morphologies with smooth surfaces, but when the shell fluid flow rate was increased to 0.5 the fiber integrity was compromised. FA was found to be amorphously distributed in the fibers on the basis of X-ray diffraction and differential scanning calorimetry results. This can be attributed to good compatibility between the drug and carrier: IR spectra indicated the presence of hydrogen bonds between the two. In vitro dissolution tests demonstrated that there was minimal FA release at pH 2.0, and sustained release in a neutral dissolution medium. The latter occurred through an erosion mechanism. During the dissolution processes, the shellac fibers were gradually converted into nanoparticles as the FA was freed into solution, and ultimately completely dissolved. [ABSTRACT FROM AUTHOR]

The present study reports a new type of sedative nanofiber membranes that were developed to permit very rapid oral delivery of helicid with concomitant taste masking. A coaxial electrospinning process was exploited to prepare core-shell nanofibers and to control the spatial depositions of different functional components. A series of tests was undertaken to characterize the resultant nanofibers. Following optimization of the electrospinning parameters, two types of core-shell nanofibers with average diameters of 730 ± 140 and 770 ± 160 nm were successfully prepared. These had uniform linear morphologies and clear core-shell structures, as verified by scanning and transmission electron microscopy images. The fibers contained sucralose in the shell and helicid in the core; X-ray diffraction demonstrated that both functional components were present in the amorphous physical form. There is significant hydrogen bonding between the functional components and the poly(vinylpyrrolidone) used as the carrier matrix, as shown from Fourier transform infrared spectroscopy and molecular mechanics simulations. In vitro dissolution tests showed that the formulations were able to release the entire incorporated drug extremely rapidly (within 1 min) when they encountered a dissolution medium, whereas the commercially available product released only 13.4 % of its drug loading in the same time. By tailoring the distribution of functional ingredients in electrospun core-shell structures, new drug delivery systems which can both accelerate dissolution and also mask unpleasant tastes were produced. [ABSTRACT FROM AUTHOR]

This study reports on novel fast-dissolving core-shell composite microparticles of quercetin fabricated using coaxial electrospraying. A PVC-coated concentric spinneret was developed to conduct the electrospray process. A series of analyses were undertaken to characterize the resultant particles in terms of their morphology, the physical form of their components, and their functional performance. Scanning and transmission electron microscopies revealed that the microparticles had spherical morphologies with clear core-shell structure visible. Differential scanning calorimetry and X-ray diffraction verified that the quercetin active ingredient in the core and sucralose and sodium dodecyl sulfate (SDS) excipients in the shell existed in the amorphous state. This is believed to be a result of second-order interactions between the components; these could be observed by Fourier transform infrared spectroscopy. In vitro dissolution and permeation studies showed that the microparticles rapidly released the incorporated quercetin within one minute, and had permeation rates across the sublingual mucosa around 10 times faster than raw quercetin. [ABSTRACT FROM AUTHOR]

The influence of different types of solvents as sheath fluids on the quality of electrospun ethyl cellulose (EC) nanofibers is investigated in this paper by a modified coaxial process. With 24 w/v % EC in ethanol as electrospinning core fluid and pure solvents including methanol, ethanol and N,N-dimethyl formamide (DMF) as sheath fluids, EC nanofibers were generated by the modified processes. Field emission scanning electron microscope observations demonstrate that the modified process is effective in improving the nanofibers' quality in terms of nanofibers' diameters, distributions and structural uniformity. The key of the modified coaxial process is the reasonable selection of the sheath solvents that is suitable for the drawing process of core EC fluid during the electrpospinning. The EC nanofibers' diameters (D, nm) could be manipulated through the reasonable selection of the type of the sheath solvents based on their boiling point (T, °C) D = 841-3.71T (R=0.9753). This paper provides useful methods for the implementation of the modified coaxial process controllably to obtain polymer nanofibers with high quality. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the preparation of ibuprofen/zein microcomposites using a modified electrospraying process, in which the spraying head was coated with an epoxy resin to prevent clogging. Scanning electron microscopy images demonstrated that the microparticles from the modified process (1.78±0.31μm) had more homogeneous structures with narrower size distributions than those (1.84±0.64μm) from the traditional route. Differential scanning calorimetry analyses verified that the guest drug ibuprofen was converted into an amorphous state in all the zein-based composites. Compared with those from the traditional process, the microparticulate composites from the modified process provided better sustained drug release profiles, as indicated by in vitro dissolution tests. The novel preparation method reported here will facilitate the preparation of new functional materials using electrospraying. [Copyright &y& Elsevier]

Abstract: This study investigated a novel type of drug-delivery membrane prepared by a modified coaxial electrospinning process. Using 1% (w/v) unspinnable zein solution as sheath fluid, the coaxial electrospinning process can be smoothly conducted to generate ketoprofen (KET)-loaded zein nanofibers coated with a thin layer of blank zein. Scanning electron microscopy and transmission electron microscopy images demonstrated that the nanofibers had a ribbon morphology with a smooth surface, as well as average diameters of 860±210nm (coating thickness of ca. 20nm) and 680±140nm (coating thickness of ca. 30nm) at sheath-to-core flow rate ratios of 0.11 and 0.25, respectively. X-ray diffraction and differential scanning calorimetry verified that KET presented an amorphous state in all nanofibers. Attenuated total reflectance Fourier transform infrared spectroscopy demonstrated that zein had good compatibility with KET because of hydrogen bonding. In vitro dissolution tests showed that the nanofibers coated with blank zein did not exert any initial burst release effect, and can enable linear drug release over a period of 16h via a diffusion mechanism. The modified coaxial electrospinning process can provide new approaches to the development of nanofiber membranes with improved structural characteristics and performance. [Copyright &y& Elsevier]

The influence of different types of solvents as sheath fluids on the quality of electrospun ethyl cellulose (EC) nanofibers is investigated in this paper by a modified coaxial process. With 24 w/v % EC in ethanol as electrospinning core fluid and pure solvents including methanol, ethanol and N,N-dimethyl formamide (DMF) as sheath fluids, EC nanofibers were generated by the modified processes. Field emission scanning electron microscope observations demonstrate that the modified process is effective in improving the nanofibers' quality in terms of nanofibers' diameters, distributions and structural uniformity. The key of the modified coaxial process is the reasonable selection of the sheath solvents that is suitable for the drawing process of core EC fluid during the electrpospinning. The EC nanofibers' diameters (D, nm) could be manipulated through the reasonable selection of the type of the sheath solvents based on their boiling point (T, °C) D = 841-3.71T (R=0.9753). This paper provides useful methods for the implementation of the modified coaxial process controllably to obtain polymer nanofibers with high quality. [ABSTRACT FROM AUTHOR]

The present research investigates a modified coaxial process for smoothening electrospinning of cellulose acetate (CA) and obtaining its nanofibers with high quality. With 11 w/v% CA in mixed solvent of acetone and N,N-dimethylacetamide (DMAc) (v:v, 3:1) as electrospinnable core fluid, different solvents (acetone, DMAc and their mixture) are taken as sheath fluids to conduct the modified process. SEM observations demonstrate that the modified process is effective in retarding the clogging of spinneret for a smooth electrospinning and in obtaining high quality CA nanofibers in terms of structural uniformity, diameters, and their distributions. The mechanism about the influence of sheath fluid on the process and the formation of nanofibers is discussed. The key for the modified coaxial process is the reasonable selection of sheath fluids and a sheath-to-core flow rate ratio matching the drawing process of core CA fluid during the electrospinning. The present paper provides a simple method to implement the modified coaxial process for smoothening the electrospinning and obtaining polymer nanofibers with high quality. [ABSTRACT FROM AUTHOR]

Abstract: This study investigates the use of a modified coaxial electrospinning process in the production of drug-loaded cellulose acetate (CA) nanofibers. With CA employed as a filament-forming matrix and ketoprofen (KET) as an active pharmaceutical ingredient, modified coaxial processes using sheath fluids comprising only mixed solvents were undertaken. With a sheath-to-core flow rate ratio of 0.2:1, the nanofibers prepared from the coaxial process had a smaller average diameter, narrower size distribution, more uniform structures, and smoother surface morphologies than those generated from single fluid electrospinning. In addition, the coaxial fibers provided a better zero-order drug release profile. The use of a sheath solvent means that the core jet is subjected to electrical drawing for a longer period, facilitating homogeneous core jet solidification and retarding the formation of wrinkles on the surface of the nanofibers. This modified coaxial electrospinning protocol allows the systematic fabrication of functional polymer nanofibers with improved quality. [Copyright &y& Elsevier]

Abstract: With sodium dodecylbenzene sulfonate (SDBS) solutions in N,N-Dimethylformamide (DMF) as sheath fluids to surround the core polymer solutions, a series of polyacrylonitrile (PAN) nanofibers with fine diameters, narrow diameter distributions, smooth surfaces and uniform structures have been successfully generated. The fiber diameters (D, nm) could be manipulated through adjusting the SDBS concentration in the sheath fluid (C, mgml−1) with a scaling law of D =790 C −0.41 (R 2 =0.9903) within a range of 5–50mgml−1. The mechanism of sheath SDBS solutions on the evaporation of DMF and the solidification of core polymer jets is discussed. The replacement of SDBS solutions for traditional atmosphere in single fluid electrospinning can lend itself to smoothen the electrospinning process through adjusting the core solvent evaporation rate. It is concluded that coaxial electrospinning with an ion surfactant solution comprises a facile process for producing high quality polymer nanofibers. [Copyright &y& Elsevier]

Sustained-release ethyl cellulose (EC) micro-particles were prepared by electrospraying. Ketoprofen (KET) was taken as a model drug and various concentrations of EC functioned as a rate-controlling polymer. The morphology of the micro-particles was assessed using SEM. Images showed that as EC content increased, the granules shared similar surface characteristics containing pure EC. Micro-particle structures were analyzed by DSC, XRD, and FTIR. It was noted that the crystalline drug was converted into an amorphous form in all the granulations and that there was chemical interaction between KET and EC observed from FTIR. Dissolution studies revealed that as the amount of EC increased, the drug release rate decreased. This investigation suggests that electrospraying can be exploited as a useful tool for developing novel particulate drug delivery systems. [ABSTRACT FROM AUTHOR]

A modified co-axial electrospinning process including electrolyte solution as sheath fluid for preparing high quality polymer nanofibers is investigated. A series of polyacrylonitrile (PAN) nanofibers were fabricated utilizing the modified process with sodium thiocyanate solutions in N, N-dimethylacetamide (DMAc) as sheath fluids. Field-emission scanning electron microscopy results demonstrated that the sheath sodium thiocyanate solutions had significant influence on the quality of PAN nanofibers. High quality PAN nanofibers in terms of fiber diameters and their distributions, surface morphology and structure have been successfully produced. The diameters of nanofibers ( D, nm) could be manipulated simply by adjusting the concentrations of sodium thiocyanate ( C, mg ml) in the sheath fluids with a scaling law of D = 324 C. The mechanism about the influence of sodium thiocyanate solutions on the formation of PAN fibers is discussed and it is felt that co-axial electrospinning with electrolyte solution is a facile process for achieving high quality polymer nanofibers. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: Third generation solid dispersions (SDs) of ferulic acid (FA) in composite nanofibers were prepared using electrospinning. The spinning liquids involved co-dissolving solutions of FA, polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and sucralose in 75% ethanol aqueous solutions. FESEM observations showed that the nanofibers were assembled in a homogeneous web structure that had a smooth cross-section and surface with an average diameter of 254±32nm. Results from DSC and XRD suggested that FA, SDS and sucralose were distributed in the PVP fibers in an amorphous manner and this is due to their compatibility resulting through a second-order interactions, as demonstrated by ATR-FTIR spectra. In vitro dissolution and permeation tests showed that the nanofiber-based SDs could release all the contained FA within 1min and had a 13-fold higher permeation rate across sublingual mucosa compared to crude FA particles. The casting films have the same compositions as the nanofibers and belong to the third generation SDs, they gave the same solubility of FA as the nanofibers, and also exhibited a much faster dissolution rate than pure FA particles. It felt that electrospinning can be taken to prepare new generation SDs with structural characteristics that enhancing absorbance of poorly soluble drugs. [ABSTRACT FROM AUTHOR]

Abstract: An elevated temperature electrospinning process was developed for the preparation of drug-loaded polyacrylonitrile (PAN) ultrafine fibers. An additional apparatus for maintaining the electrospinning temperature at a high constant value was fitted on the syringe pump. Acyclovir (ACY)-loaded PAN fibers could be prepared from the co-dissolving dimethyl sulfoxide solutions of PAN and ACY at 80°C. As the temperature increased, the viscosities and the surface tensions of the co-dissolving solutions decreased, whereas conductivities increased, which can account for the improved electrospinning ability of the solutions. 1H NMR analysis demonstrated that chemical integrity of ACY was maintained during the elevated temperature electrospinning process. The prepared ACY-loaded PAN ultrafine fibers had a smooth surface and uniform structure with no bead-on-a-string configurations. 94% of the fiber diameters fell within the range of 400–700nm. The X-ray diffractograms and DSC results demonstrated that almost all the ACY was able to be distributed in the PAN fiber matrix in an amorphous status. The FTIR spectra demonstrated that PAN and ACY had sufficient compatibility due to hydrogen bonding. In vitro dissolution tests exhibited that the fibers could provide sustained drug release profiles over a time period of 16h. The study demonstrates that an elevated temperature electrospinning process is able to broaden the processing window and enabling the preparation of new types of functional fibers with high quality. [Copyright &y& Elsevier]

Solid dispersions of ketoprofen in nanofibers were prepared using electrospinning process with polyvinylpyrrolidone as the filament-forming polymer. Results from differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and fourier-transform infrared suggested that ketoprofen was well distributed in the polymer nanofibers in an amorphous solid dispersion state due to the hydrogen bonding between them. In vitro wetting and dissolution tests showed that the nanofibers could absorb water from the wet papers and wetted within several seconds, and ketoprofen could be exhausted within 30 seconds. Electrospinning is a useful process for the preparation of solid dispersions. [ABSTRACT FROM AUTHOR]

Abstract: Novel doughnut-shaped multi-layered drug delivery devices (DDDs) were developed with local variations of the drug and release-retardant material for providing linear release profiles. Based on computer-aided design models, different DDDs containing acetaminophen as a model drug, hydroxypropyl methylcellulose as matrix and ethyl cellulose (EC) as a release-retardant material were prepared automatically using a three-dimensional printing (3DP) system. In vitro dissolution assays demonstrated that all the 3DP DDDs had with different diameters, heights, concentrations of EC and central hole diameters were able to give linear release profiles. Morphological and erosion studies showed that acetaminophen was released through a simultaneous surface erosion process involving the outer peripheries and inner apertures. The barrier layers on both bases of DDDs had good adhesion strength with the drug-contained regions and offered consistent release retardation for the whole duration of the dissolution process. The release time periods of the DDDs were dependent on the annular thicknesses or the passes of binder solution containing a release-retardant material. The dosage of the DDD can be adjusted independently by changing the heights of the DDDs. Thus, 3DP is capable of offering novel strategies for developing DDDs with complex design features for desired drug release profiles. [Copyright &y& Elsevier]

Abstract: Tamoxifen microcapsules and drug loaded medicated fabrics were investigated. The microcapsules were prepared using a complex coacervation procedure involving gelatin B and acacia gum. The morphology, particle size, drug loading capacity and in vitro release characteristics of the drug microcapsules were optimized for coating tamoxifen microcapsules onto the cotton fabrics. Infrared (IR) spectra and SEM were used to characterize the medicated fabrics and air permeability and laundering testing were undertaken to determine the efficiency and effectiveness of the system. Results showed that optimum condition for the microcapsules was at drug/polymer ratio 1:4, polymer concentration 3%, and rate of stirring 1000rpm. In vitro release assays demonstrated that the tamoxifen was liberated over 10h after an initial bust rate period. SEM images illustrated that the tamoxifen microcapsules were spherical in shape and were also tightly fixed on to the cotton fabrics fast. These observations demonstrate that we have designed and fabricated a medicated system that potentially could be applied within a transdermal drug delivery system and so act in a system for the treatment of breast cancer. [Copyright &y& Elsevier]

Three-dimensional printing (3DP) is a rapid prototyping (RP) technology. Prototyping involves constructing specific layers that uses powder processing and liquid binding materials. Reports in the literature have highlighted the many advantages of the 3DP system over other processes in enhancing pharmaceutical applications, these include new methods in design, development, manufacture, and commercialization of various types of solid dosage forms. For example, 3DP technology is flexible in that it can be used in applications linked to linear drug delivery systems (DDS), colon-targeted DDS, oral fast disintegrating DDS, floating DDS, time controlled, and pulse release DDS as well as dosage form with multiphase release properties and implantable DDS. In addition 3DP can also provide solutions for resolving difficulties relating to the delivery of poorly water-soluble drugs, peptides and proteins, preparation of DDS for high toxic and potent drugs and controlled-release of multidrugs in a single dosage forms. Due to its flexible and highly reproducible manufacturing process, 3DP has some advantages over conventional compressing and other RP technologies in fabricating solid DDS. This enables 3DP to be further developed for use in pharmaceutics applications. However, there are some problems that limit the further applications of the system, such as the selections of suitable excipients and the pharmacotechnical properties of 3DP products. Further developments are therefore needed to overcome these issues where 3DP systems can be successfully combined with conventional pharmaceutics. Here we present an overview and the potential 3DP in the development of new drug delivery systems. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:3666–3690, 2008 [ABSTRACT FROM AUTHOR]

For the first time, biocompatible and biodegradable Ta-metal organic framework (MOF) polyether block amide (PEBA) fibrous polymeric nanostructures were synthesized by ultrasonic and electrospinning routes in this study. The XRD peaks of products were wider, which is due to the significant effect of the ultrasonic and electrospinning methods on the final product. The adsorption/desorption behavior of the nanostructures is similar to that of the third type of isotherm series, which showed mesoporous behavior for the products. The sample has uniform morphology without any evidence of agglomeration. Since the adsorption and trapping of gaseous pollutants are very important, the application of the final Ta-MOF/PEBA fibrous polymeric nanostructures was investigated for CH4 adsorption. In order to achieve the optimal conditions of experiments and also systematic studies of the parameters, fractional factorial design was used. The results showed that by selecting temperature 40°C, time duration 35 min, and pressure 3 bar, the >H4 gas adsorption rate was near 4 mmol/g. Ultrasonic and electrospinning routes as well as immobilization of Ta-MOF in the PEBA fibrous network affect the performance of the final products for CH4 gas adsorption. [ABSTRACT FROM AUTHOR]

In this study, three kinds of electrohydrodynamic atomization (EHDA) processes (electrospraying, electrospinning, and coaxial electrospinning) are implemented to create hydroxypropyl methylcellulose (HPMC) based ultra‐thin products for providing the fast dissolution of a poorly water‐soluble drug ketoprofen (KET). An EHDA apparatus, characterized by a novel spinneret, is homemade for conducting the three processes. The three types of products are electrospun nanofibers E1, electrosprayed microparticles E2, and core‐shell nanofibers E3. SEM and TEM results indicate that they have the anticipated morphologies and inner structures. X‐ray diffraction and Fourier Transform Infrared results verify that KET is mainly amorphous in all the composites due to its fine compatibility with HPMC. In vitro dissolution tests demonstrate that the drug rapid release performances has an order of E3>E1>E2≫KET powders. The fast dissolution mechanisms are suggested and the advantages of the three products are compared. The super performance of E3 in furnishing the rapid release is attributed to a synergistic action of small size (of the shell thickness), high porosity, amorphous state of drug, and the solubility of HPMC. EHDA nanostructures can support the development of nano drug delivery systems (DDSs) through tailoring the spatial distribution of drug molecules within the nano products. [ABSTRACT FROM AUTHOR]

Dressings with multiple functional performances (such as hemostasis, promoting regeneration, analgesia, and anti-inflammatory effects) are highly desired in orthopedic surgery. Herein, several new kinds of medicated nanofibers loaded with several active ingredients for providing multiple functions were prepared using the modified coaxial electrospinning processes. With an electrospinnable solution composed of polycaprolactone and fenoprofen as the core working fluid, several different types of unspinnable fluids (including pure solvent, nanosuspension containing tranexamic acid and hydroxyapatite, and dilute polymeric solution comprising tranexamic acid, hydroxyapatite, and polyvinylpyrrolidone) were explored to implement the modified coaxial processes for creating the multifunctional nanofibers. Their morphologies and inner structures were assessed through scanning and transmission electron microscopes, which all showed a linear format without the discerned beads or spindles and a diameter smaller than 1.0 μm, and some of them had incomplete core–shell nanostructures, represented by the symbol @. Additionally, strange details about the sheaths' topographies were observed, which included cracks, adhesions, and embedded nanoparticles. XRD and FTIR verified that the drugs tranexamic acid and fenoprofen presented in the nanofibers in an amorphous state, which resulted from the fine compatibility among the involved components. All the prepared samples were demonstrated to have a fine hydrophilic property and exhibited a lower water contact angle smaller than 40° in 300 ms. In vitro dissolution tests indicated that fenoprofen was released in a sustained manner over 6 h through a typical Fickian diffusion mechanism. Hemostatic tests verified that the intentional distribution of tranexamic acid on the shell sections was able to endow a rapid hemostatic effect within 60 s. [ABSTRACT FROM AUTHOR]

Abstract: A modified co-axial electrospinning process using salt solutions as sheath fluids for preparing polymer nanofibers was investigated. A series of polyvinylpyrrolidone (PVP) fibers were prepared with NaCl aqueous solutions at varying concentrations as sheath fluids. The sheath fluid had a significant influence on the formation of the compound Taylor cone. Scanning electron microscopy results demonstrated that the diameters of PVP nanofibers could be manipulated through the concentration of NaCl solutions within an appropriate range. With 2mgml−1 NaCl solution as sheath fluid, the smallest PVP nanofibers, with a diameter of 120±40nm, were obtained. Co-axial electrospinning with salt solutions as sheath fluids is a facile method for achieving finer, homogeneous polymer nanofibers. [Copyright &y& Elsevier]

We show that coaxial electrospinning using organic solvent as the sheath fluid is a viable way to produce tailor-made nanofibers composed of polyvinylpyrrolidine, tristearic and naproxen. Self-assembled hybrid nanoparticles are generated from the composite nanofibers under aqueous conditions and particle size has a linear relationship with fiber diameter. [ABSTRACT FROM AUTHOR]

The growing demand for fuel and industrial products has resulted in increased global CO2 emissions, which has accelerated global warming and made this an issue of widespread concern. Therefore, there is an urgent need to develop improved methods for CO2 fixation and conversion. Porous organic polymers (POPs) are solid frameworks that can be used for this purpose and can be prepared by so-called "bottom-up" methods. Being one kind of POP, hypercrosslinked polymers (HCPs) have emerged as a promising platform for CO2 capture and conversion, because of their high specific surface areas, variable pore characteristics, superior stabilities, and modifiable surface functionalities. In addition, innovative green methods of synthesis enable the environmentally friendly production of HCPs. In this review, we provide an update on the synthesis and utilization of HCPs for CO2 capture and conversion. First, we introduce green routes for the synthesis of HCPs, followed by a comprehensive summary of various methods for CO2 capture and conversion. Our primary emphasis is on the utilization of HCPs for CO2 fixation (gas storage) and gas separation, with particular attention given to CO2 selectivity and recoverability. Additionally, we explore the potential of HCPs in the conversion of CO2 into valuable compounds. Ultimately, we present thought-provoking suggestions to facilitate the future advancement of CO2 fixation technologies, harnessing the inherent capabilities of HCPs. [ABSTRACT FROM AUTHOR]

Polymers are the backbone of drug delivery. Electrospinning has greatly enriched the strategies that have been explored for developing novel drug delivery systems using polymers during the past two decades. In this study, four different kinds of polymers, i.e., the water-soluble polymer poly (vinyl alcohol) (PVA), the insoluble polymer poly(ε-caprolactone) (PCL), the insoluble polymer Eudragit RL100 (ERL100) and the pH-sensitive polymer Eudragit S100 (ES100) were successfully converted into types of tri-layer tri-polymer core–shell fibers through bi-fluid coaxial electrospinning. During the coaxial process, the model drug metronidazole (MTD) was loaded into the shell working fluid, which was an emulsion. The micro-formation mechanism of the tri-layer core–shell fibers from the coaxial emulsion electrospinning was proposed. Scanning electron microscope and transmission electron microscope evaluations verified the linear morphology of the resultant fibers and their obvious tri-layer multiple-chamber structures. X-ray diffraction and Fourier transform infrared spectroscopy measurements demonstrated that the drug MTD presented in the fibers in an amorphous state and was compatible with the three polymeric matrices. In vitro dissolution tests verified that the three kinds of polymer could act in a synergistic manner for a prolonged sustained-release profile of MTD in the gut. The drug controlled-release mechanisms were suggested in detail. The protocols reported here pioneer a new route for creating a tri-layer core–shell structure from both aqueous and organic solvents, and a new strategy for developing advanced drug delivery systems with sophisticated drug controlled-release profiles. [ABSTRACT FROM AUTHOR]

Smart drug delivery, through which the drug molecules are delivered according to the requests of human biological rhythms or by maximizing drug therapeutic effects, is highly desired in pharmaceutics. Many biomacromolecules have been exploited for this application in the past few decades, both in industry and laboratories. Biphasic release, with an intentional pulsatile release and a following extended release stage, represents a typical smart drug delivery approach, which aims to provide fast therapeutic action and a long time period of effective blood drug concentration to the patients. In this study, based on the use of a well-known biomacromolecule, i.e., cellulose acetate (CA), as the drug (acetaminophen, ATP)-based sustained release carrier, a modified coaxial electrospraying process was developed to fabricate a new kind of core–shell nanoparticle. The nanoparticles were able to furnish a pulsatile release of ATP due to the shell polyvinylpyrrolidone (PVP). The time cost for a release of 30% was 0.32 h, whereas the core–shell particles were able to provide a 30.84-h sustained release of the 90% loaded ATP. The scanning electron microscope and transmission electron microscope results verified in terms of their round surface morphologies and the obvious core–shell double-chamber structures. ATP presented in both the core and shell sections in an amorphous state owing to its fine compatibility with CA and PVP. The controlled release mechanisms of ATP were suggested. The disclosed biomacromolecule-based process–structure–performance relationship can shed light on how to develop new sorts of advanced nano drug delivery systems. [ABSTRACT FROM AUTHOR]

With the great demand for flexible self‐powered sensors and nanogenerators, polyvinylidene fluoride (PVDF) is widely investigated for outstanding piezoelectric and dielectric constant. In the pursuit for increasing β content, electrospinning is exhibited to be an effective method without external high voltage pooling or mechanical stretching and thus is considered a cost‐effective and simple method, because the molecular dipoles in the PVDF can be aligned during the process of electrospinning with high voltage field and stretching. The methods for improving piezoelectric characteristics are briefly introduced in this review, electrospinning fibers including uniaxial fibers, highly aligned fibers, core–shell fibers and Janus fibers are revealed, and research on theoretical modeling is carried out for efficiency in the design of piezoelectric nanogenerator. Last, studies on prospective applications based on electrospun PVDF and its copolymer PVDF‐TrFE, from sensors to smart skin, from energy harvesters to electronic textiles, are being conducted. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A modified tri-axial electrospinning with un-spinnable outer and middle fluids. • The middle fluid flow rate was varied to control the thickness of the shell. • Incrementally variable zero-order drug release profiles can be achieved. • A mathematical process-structure-performance relationship is revealed. Abstract The ability to accurately control a material's structure, and in turn its functional performance, is of crucial importance for potential applications. In this study, a new modified triaxial electrospinning process was successfully developed to allow us to precisely tune drug release from nanoscale formulations. In this process, we used two un-electrospinnable liquids as the outer and middle working fluids, with only the core solution being individually electrospinnable into fibers. The outer liquid comprised a mixture of solvents, while the middle fluid was a dilute solution of cellulose acetate (CA). The core fluid was an electrospinnable co-dissolving solution of ferulic acid (FA) and gliadin. By processing these in triaxial electrospinning, we were able to create FA-gliadin fibers coated with a thin but even and continuous coating of CA. The thickness of the CA coating could be precisely varied by adjusting the flow rate of the middle working fluid. The resultant nanofibers have linear and cylindrical morphologies with clear core-shell structures. X-ray diffraction and IR spectroscopy data verified that the fibers comprised amorphous solid dispersions, with intermolecular interactions existing between FA and gliadin. The CA coating eliminated the initial burst release seen with uncoated FA-gliadin fibers, and also led to close to zero-order release profiles which could be incrementally adjusted by varying the thickness of the coating. New process-nanostructure-performance relationships are therefore revealed, and the advanced triaxial electrospinning approach reported in this work has great potential for developing new kinds of functional nanomaterials. [ABSTRACT FROM AUTHOR]

Abstract Nanotechnology has been extensively explored for the potential applications in developing materials for sustained drug release. In this study, a modified coaxial electrospinning, characterized by a detachable concentric spinneret, was developed for the fabrication of a new kind of hybrid structural nanomaterials. The hybrid nanofibers consisted of a drug-free thin layer of glycerol monostearate as the shell and a drug-loaded nanocomposite containing berberine hydrochloride and ethylcellulose as the core, which were confirmed by scanning electron microscopic and transmission electron microscopic results. X-ray diffraction analyses suggested that the drug berberine hydrochloride was converted into an amorphous state with the carrier ethylcellulose in the core section. Fourier transform infrared spectra suggested that all the components were compatible. In vitro dissolution tests verified that the structural hybrids can provide an improved drug sustained-release profile than monolithic medicated nanocomposites in terms of initial burst release, sustained-release time and tailing-off time. The mechanism involving the influences of sheath layer on the drug release behaviour was suggested. The reported protocols pave a new way for fabricating lipid–polymer-based functional nanostructures with accurate structure–property–performance relationship and are useful for developing a series of new functional nanomaterials. Graphical abstract Unlabelled Image Highlights • A structural fiber with drug-free lipid on the medicated nanocomposite was studied. • Unspinnable lipid solution was explored as the sheath working fluid. • The lipid-coated fibers could provide an improved drug sustained release profile. • Clear structure–property–performance relationship was disclosed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A triaxial electrospinning characterized by a new detachable tri-layer spinneret. • A blank cellulose acetate layer was precisely coated on medicated nanocomposites. • A tunable sustained release profile of a poorly water-soluble drug. • A clear process-structure-performance relationship was disclosed. Abstract In this study, novel core-shell nanostructures were fabricated through a modified triaxial electrospinning process. These comprised a drug-protein nanocomposite coated with a thin cellulose acetate (CA) shell. They were generated through the simultaneous treatment of an outer solvent, an unelectrospinnable middle fluid, and an electrospinnable core solution in triaxial electrospinning. SEM and TEM results revealed that the core-shell nanofibers had linear and cylindrical morphologies with a diameter from 0.66 to 0.87 μm, and distinct core-shell structures with a shell thickness from 1.8 to 11.6 nm. The presence of a CA coating eliminated the initial burst release of ibuprofen seen from a monolithic drug-protein composite, and allowed us to precisely manipulate the drug release (for a 90% percentage) over a time period from 23.5 to 43.9 h in a tunable manner. Mathematical relationships between the processing conditions, the nanostructures produced, and their functional performance were elucidated. [ABSTRACT FROM AUTHOR]

Structural nanocomposites that provide fast dissolving drug release profiles are highly in demand in pharmaceutics. In this study, a poorly water-soluble drug such as quercetin or tamoxifen citrate (TC) was selected as a model active pharmaceutical ingredient. Core-shell nanofibers with ultra-thin shells were designed and prepared using modified coaxial electrospinning. Polyvinylpyrrolidone (PVP) K90 or Polycaprolactone (PCL) was selected as core. The drugs and PVP K10 were selected as shell. All types of solutions can be used as the shell fluids in modified coaxial process regardless of their electrospinnability, which means the increasing functional ingredients and unspinnable matrix can be processed. Evaluations via SEM and TEM demonstrated that the core-shell nanofibers had linear morphology with a shell thickness smaller than 100 nm. XRD and FTIR results showed that the model drug was distributed in the polymeric matrix amorphously and that PVP K10 had good compatibility with quercetin or TC. In vitro dissolution tests suggested that the core-shell nanofibers with ultra-thin shells released the loaded cargoes in the dissolution media within 1 min. The present investigation paved a new way for implementing the modified coaxial processes, which can be utilized to fabricate structural nanocomposites with ultra-thin shells for enhancing the fast dissolution of poorly water-soluble drugs. [ABSTRACT FROM AUTHOR]

In this nano era, nanomaterials and nanostructures are popular in developing novel functional materials. However, the combinations of materials at micro and macro scales can open new routes for developing novel trans-scale products with improved or even new functional performances. In this work, a brand-new hybrid, containing both nanofibers and microparticles, was fabricated using a sequential electrohydrodynamic atomization (EHDA) process. Firstly, the microparticles loaded with drug (berberine hydrochloride, BH) molecules in the cellulose acetate (CA) were fabricated using a solution electrospraying process. Later, these microparticles were suspended into a co-dissolved solution that contained BH and a hydrophilic polymer (polypyrrolidone, PVP) and were co-electrospun into the nanofiber/microparticle hybrids. The EHDA processes were recorded, and the resultant trans-scale products showed a typical hybrid topography, with microparticles distributed all over the nanofibers, which was demonstrated by SEM assessments. FTIR and XRD demonstrated that the components within the hybrids were presented in an amorphous state and had fine compatibility with each other. In vitro dissolution tests verified that the hybrids were able to provide the designed dual-step drug release profiles, a combination of the fast release step of BH from the hydrophilic PVP nanofibers through an erosion mechanism and the sustained release step of BH from the insoluble CA microparticles via a typical Fickian diffusion mechanism. The present protocols pave a new way for developing trans-scale functional materials. [ABSTRACT FROM AUTHOR]

Colon-targeted drug delivery is gradually attracting attention because it can effectively treat colon diseases. Furthermore, electrospun fibers have great potential application value in the field of drug delivery because of their unique external shape and internal structure. In this study, a core layer of hydrophilic polyethylene oxide (PEO) and the anti-colon-cancer drug curcumin (CUR), a middle layer of ethanol, and a sheath layer of the natural pH-sensitive biomaterial shellac were used in a modified triaxial electrospinning process to prepare beads-on-the-string (BOTS) microfibers. A series of characterizations were carried out on the obtained fibers to verify the process–shape/structure–application relationship. The results of scanning electron microscopy and transmission electron microscopy indicated a BOTS shape and core–sheath structure. X-ray diffraction results indicated that the drug in the fibers was in an amorphous form. Infrared spectroscopy revealed the good compatibility of the components in the fibers. In vitro drug release revealed that the BOTS microfibers provide colon-targeted drug delivery and zero-order drug release. Compared to linear cylindrical microfibers, the obtained BOTS microfibers can prevent the leakage of drugs in simulated gastric fluid, and they provide zero-order release in simulated intestinal fluid because the beads in BOTS microfibers can act as drug reservoirs. [ABSTRACT FROM AUTHOR]

This study presents a glucose biosensor based on electrospun core–sheath nanofibers. Two types of film were fabricated using different electrospinning procedures. Film F1 was composed solely of core–sheath nanofibers fabricated using a modified coaxial electrospinning process. Film F2 was a double-layer hybrid film fabricated through a sequential electrospinning and blending process. The bottom layer of F2 comprised core–sheath nanofibers fabricated using a modified process, in which pure polymethacrylate type A (Eudragit L100) was used as the core section and water-soluble lignin (WSL) and phenol were loaded as the sheath section. The top layer of F2 contained glucose oxidase (GOx) and gold nanoparticles, which were distributed throughout the polyvinylpyrrolidone K90 (PVP K90) nanofibers through a single-fluid blending electrospinning process. The study investigated the sequential electrospinning process in detail. The experimental results demonstrated that the F2 hybrid film had a higher degradation efficiency of β-D-glucose than F1, reaching a maximum of over 70% after 12 h within the concentration range of 10–40 mmol/L. The hybrid film F2 is used for colorimetric sensing of β-D-glucose in the range of 1–15 mmol/L. The solution exhibited a color that deepened gradually with an increase in β-D-glucose concentration. Electrospinning is flexible in creating structures for bio-cascade reactions, and the double-layer hybrid film can provide a simple template for developing other sensing nanomaterials. [ABSTRACT FROM AUTHOR]

Dyes, antibiotics, heavy metal ions, and bacteria are important sources of water pollution. How to solve these issues has become a problem in the fields of science and technology. People have developed a variety of technologies to treat pollutants in water. Photocatalytic technology came into being. As a simple and environmentally friendly treatment technology, it has been widely studied by the scientific community. Traditional powder photocatalysts cause secondary pollution to the environment and are not conducive to recycling. Therefore, large specific surface area and reusable membrane photocatalysts built by electrospinning technology have become a favorite of today's scientific community. Nanofiber membranes prepared by electrospinning technology have a variety of structures, which can meet the needs of different occasions. This review summarizes and discusses research progress in electrospinning technology, the relationship between the structure and treatment of electrospun fiber membranes, and their impacts on the photocatalytic performance of nanofiber membranes. The performance, challenges, and future development directions of nanofiber membranes with different structures, prepared by different kinds of electrospinning techniques using photocatalysis to treat different pollutants, are reviewed. [ABSTRACT FROM AUTHOR]

Electrospinning is considered to be an efficient method to prepare piezoelectric thin films because of its ability to transform the phase of the polymers. A core-sheath structure can endow fibers with more functions and properties. In this study, fibers with a core-sheath structure were prepared using polyvinylidene fluoride (PVDF) included with nanoparticles (NPs) as the shell layer and polycaprolactone (PCL) as the core layer. Their mechanical and piezoelectric properties were studied in detail. During the course of the electrospinning process, PVDF was demonstrated to increase the amount of its polar phase, with the help of nanoparticles acting as a nucleating agent to facilitate the change. PCL was chosen as a core material because of its good mechanical properties and its compatibility with PVDF. Transmission electron microscope (TEM) assessments revealed that the fibers have a core-sheath structure, and shell layers were loaded with nanoparticles. Mechanical testing showed that the core layer can significantly improve mechanical properties. The XRD patterns of the core-sheath structure fibers indicated the β phase domain the main component. Piezoelectric testing showed that the doped nanoparticles were able to enhance piezoelectric performances. The increases of mechanical and piezoelectric properties of core-sheath structure fibers provide a feasible application for wearable electronics, which require flexibility and good mechanical properties. [ABSTRACT FROM AUTHOR]

Advanced medicated nanomaterials that provide time- and target-specific drug release profiles are highly desired for efficacious drug delivery. In this study, a structural nanocomposite (P2) consisted of tamoxifen citrate (TC) and polyvinylpyrrolidone (PVP) (2:8, w:w) as core and shellac as shell was designed and fabricated using a modified coaxial electrospraying process. Shellac solution, which could not be converted into solid particles individually, was explored as a shell working fluid to encapsulate the core TC-PVP blending solution, which could be electrosprayed into solid particles (P1) all alone. SEM and TEM evaluations demonstrated that the quality of the core-shell particles P2 was higher than that of the monolithic particles P1 in terms of particle diameter, size distribution and number of satellites. XRD results suggested that TC was similarly present in an amorphous state in particles P1 and P2 due to its fine compatibility with PVP, which was verified through FTIR tests. In vitro dissolution experiments suggested that P2 could provide the designed drug colon-specific delayed release characteristics, passing through acidic conditions of pH 2.0 dissolution media and freeing all of the loaded TC within 5 min at pH 7.4 dissolution media. [ABSTRACT FROM AUTHOR]