Roles of Coaxial Spinneret in Taylor Cone and Morphology of Core–Shell Fibers

Platelet-rich fibrin-loaded PCL/chitosan core-shell fibers scaffold for enhanced osteogenic differentiation of mesenchymal stem cells

Here, we fabricated the platelet-rich fibrin (PRF)-loaded PCL/chitosan (PCL/CS-PRF) core-shell nanofibrous scaffold through a coaxial electrospinning method. Our goal was to evaluate the effect of CS-RPF in the core layer of the nanofibrous on the osteogenic differentiation of human mesenchymal stem cells (HMSCs). The elastic modulus of PCL/CS-PRF core-shell scaffold (44 MPa) was about 1.5-fold of PCL/CS scaffold (25 MPa). The specific surface area of the scaffolds increased from 9.98 m²/g for PCL/CS scaffold to 16.66 m²/g for the PCL/CS-PRF core-shell nanofibrous scaffold. Moreover, the release rate of PRF from PCL/CS-PRF nanofibrous scaffold was measured to be 24.50% after 10 days which showed slow and sustained release of PRF from the nanofibrous. The formation of Ca-P on the surface of scaffold immersed in simulated body fluid solution indicated the suitable osteoconductivity of PCL/CS-PRF core-shell nanofibrous scaffold. Also, the value of ALP activity and calcium deposited on the surface of PCL/CS-PRF core-shell nanofibrous scaffold were 81.97 U/L and 40.33 μg/scaffold, respectively after 14 days, which confirmed the significantly higher amounts of ALP and calcium deposition on the scaffold containing PRF compared to PCL/CS scaffold. Due to higher hydrophilicity and porosity of PCL/CS-PRF core-shell nanofibrous scaffold compared to PCL/CS scaffold, a better bone cell growth on surface of PCL/CS-PRF scaffold was observed. The Alizarin red-positive area was significantly higher on PCL/CS-PRF scaffold compared to PCL/CS scaffold, indicating more calcium deposition and osteogenic differentiation of HMSCs in the presence of PRF. Our findings demonstrate that PCL/CS-PRF core-shell scaffolds can provide a strong construct with improved osteogenic for bone tissue engineering applications.

Modified Electrospun Polymeric Nanofibers and Their Nanocomposites as Nanoadsorbents for Toxic Dye Removal from Contaminated Waters: A Review

Electrospun polymer nanofibers (EPNFs) as one-dimensional nanostructures are characterized by a high surface area-to-volume ratio, high porosity, large number of adsorption sites and high adsorption capacity. These properties nominate them to be used as an effective adsorbent for the removal of water pollutants such as heavy metals, dyes and other pollutants. Organic dyes are considered one of the most hazardous water pollutants due to their toxic effects even at very low concentrations. To overcome this problem, the adsorption technique has proven its high effectiveness towards the removal of such pollutants from aqueous systems. The use of the adsorption technique depends mainly on the properties, efficacy, cost and reusability of the adsorbent. So, the use of EPNFs as adsorbents for dye removal has received increasing attention due to their unique properties, adsorption efficiency and reusability. Moreover, the adsorption efficiency and stability of EPNFs in aqueous media can be improved via their surface modification. This review provides a relevant literature survey over the last two decades on the fabrication and surface modification of EPNFs by an electrospinning technique and their use of adsorbents for the removal of various toxic dyes from contaminated water. Factors affecting the adsorption capacity of EPNFs, the best adsorption conditions and adsorption mechanism of dyes onto the surface of various types of modified EPNFs are also discussed. Finally, the adsorption capacity, isotherm and kinetic models for describing the adsorption of dyes using modified and composite EPNFs are discussed.

Impact of Apparatus Orientation and Gravity in Electrospinning-A Review of Empirical Evidence

Electrospinning is a versatile fibre fabrication method with applications from textile to tissue engineering. Despite the appearance that the influencing parameters of electrospinning are fully understood, the effect of setup orientation has not been thoroughly investigated. With current burgeoning interest in modified and specialised electrospinning apparatus, it is timely to review the impact of this seldom-considered parameter. Apparatus configuration plays a major role in the morphology of the final product. The primary difference between spinning setups is the degree to which the electrical force and gravitational force contribute. Since gravity is much lower in magnitude when compared with the electrostatic force, it is thought to have no significant effect on the spinning process. But the shape of the Taylor cone, jet trajectory, fibre diameter, fibre diameter distribution, and overall spinning efficiency are all influenced by it. In this review paper, we discuss all these developments and more. Furthermore, because many research groups build their own electrospinning apparatus, it would be prudent to consider this aspect as particular orientations are more suitable for certain applications.