This study discusses the value of polymer electrospun materials in three-dimensional (3D) scaffolds and antibacterial wound dressings for potential dental applications.

The study presents a rapid method of SnO2 shell formation on AgNWs for both high environmental stability and thermal management on para-aramid fabric.

PurposeThe study discusses the value of electrospun cilostazol-loaded (CIL) polymer structures for potential vascular implant applications.MethodsBiodegradable polycaprolactone (PCL) fibers were produced by electrospinning on a rotating drum collector. Three different concentrations of CIL: 6.25%, 12.50% and 18.75% based on the amount of polymer, were incorporated into the fibers. The fibers were characterized by their size, shape and orientation. Materials characterization was carried out by Fourier Transformed Infrared spectroscopy (FTIR), Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). In vitro drug release study was conducted using flow-through cell apparatus (USP 4).ResultsThree-dimensional structures characterized by fibers diameter ranging from 0.81 to 2.48 μm were in the range required for cardiovascular application. DSC and XRD confirmed the presence of CIL in the electrospun fibers. FTIR and Raman spectra confirmed CIL polymorphic form. Elastic modulus values for PCL and the CIL-loaded PCL fibers were in the range from 0.6 to 1.1 GPa. The in vitro release studies were conducted and revealed drug dissolution in combination with diffusion and polymer relaxation as mechanisms for CIL release from the polymer matrix.ConclusionsThe release profile of CIL and nanomechanical properties of all formulations of PCL fibers demonstrate that the cilostazol loaded PCL fibers are an efficient delivery system for vascular implant application.Electronic supplementary materialThe online version of this article (10.1007/s11095-017-2314-0) contains supplementary material, which is available to authorized users.

The review discusses the progress in the design and synthesis of bioactive agents incorporated into vascular grafts obtained by the electrospinning process.

One-dimensional (1D) ZnO nanostructures have been widely studied because of their electronic and optoelectronic applications. This report discusses the morphology, optical, electrical and sensory properties of polycrystalline ZnO nanofibers (NFs). We observed that the electrospun ceramic NFs interband emission increases with the nanocrystal size, consistent with decreasing of the surface-to-volume ratio. The observation is novel for the electrospun ceramic NFs. The chemical composition and structural characterization reveal that the NFs consist of ZnO wurzite nanocrystals, whose mean diameters increase from 7 to 22 nm with calcination temperature. Emission properties are studied by cathodo-and photoluminescence. The NFs are applied to construct light, gas and liquid sensors. We find an increase of the NFs conductivity by three orders of magnitude under UV illumination as a result of desorption of molecular oxygen from the nanocrystal surface. We study the influence of oxygen on NF conductivity by purging the NFs with air or nitrogen. We show that the flow of nitrogen removes the oxygen resulting in an important increase of the conductivity. Also, we study the dynamics of this process with and without UV illumination. We show sensitivity of the NFs to liquid environment by studying the conductivity of NFs immersed in water and ethanol and find an increased conductivity with respect to a dry air environment. These light-and environmental-sensitive ZnO NFs have useful optical and electronic properties for building high-performance sensors.

No abstract

We demonstrate structural and room temperature magnetic properties of Fe doped ZnO nanofibers (NFs) obtained by electrospinning followed by calcination. The observed NFs, formed from crystalographically oriented, approximately 4.5 nm particles conglomerates, were approximately 200 nm in diameter. The reported synthesis of room temperature ferromagnetic Fe doped ZnO NFs is both facile and economical, and is therefore suggested as a generic method of fabricating biocompatible magnetic materials. The major substrates selected for the NFs synthesis (Zn, Fe) comprised of relatively low toxicity materials. Incorporating 10% Fe into ZnO does not modify the wurtzite crystal structure of the host material. No evidence of impurity phase was detected by either X-ray or electron diffraction. Magnetometry studies and Magnetic Force Microscopy imaging reveal a local ferromagnetic order that persists up to room temperature. We suggest that the observed phenomenon is either due to a mechanism mediated by presence of oxygen vacancies and/or is related to iron-rich precipitates.

This study describes a new method of passivating ZnO nanofiber-based devices with a ZnS layer. This one-step process was carried out in H2S gas at room temperature, and resulted in the formation of core/shell ZnO/ZnS nanofibers. This study presents the structural, optical and electrical properties of ZnO/ZnS nanofibers formed by a 2 nm ZnS sphalerite crystal shell covering a 5 nm ZnO wurtzite crystal core. The passivation process prevented free carriers from capture by oxygen molecules and significantly reduced the impact of O2 on nanostructure conductivity. The conductivity of the nanofibers was increased by three orders of magnitude after the sulfidation, the photoresponse time was reduced from 1500 s to 30 s, and the cathodoluminescence intensity increased with the sulfidation time thanks to the removal of ZnO surface defects by passivation. The ZnO/ZnS nanofibers were stable in water for over 30 days, and in phosphate buffers of acidic, neutral and alkaline pH for over 3 days. The by-products of the passivation process did not affect the conductivity of the devices. The potential of ZnO/ZnS nanofibers for protein biosensing is demonstrated using biotin and streptavidin as a model system. The presented ZnS shell preparation method can facilitate the construction of future sensors and protects the ZnO surface from dissolving in a biological environment.