Electrospinning Electrospun

Brunauer-Emmett-Teller Electrospinning Electrospun polylacticacid Nanofiber mats Nylon 6... 

The experiments indicated that PVB is suitable as a matrix to form nanofibers together with poly(ardline) (PANI) by electrospinning. Electrospun PANl/PVB nanofibers exhibited a very high sensitivity of 75 kHz/% relative humidity from 20-90% relative humidity. Further, an ultrafast response of 1-2 s for humidification and desiccation was reported. In addition, the sensor could detect humidity levels as low as 0.5% relative humidity (30). 

Finally, chitosan, a polysaccharide, is another natural material commonly used for electrospinning. Electrospun chitosan has been shown to enhance chondrocyte attachment, proliferation, and conservation of the chondrocyte phenotype when compared to a chitosan-based film (Shim et al., 2009). More commonly, blending of chitosan and other natural or synthetic components have been shown to be beneficial for cell attachment, proliferation, and viability (Subramanian et al., 2005 Bhattarai et al., 2005). 

Kwon and coworkers prepared a series of nano- to microstmctured biodegradable PCLA porous fabrics by electrospinning. The nanoscale-fiber porous fabrics were electrospun with PCLA (1 1 mole ratio, approximately 0.3-1.2 mm in diameter) using l,l,l,3,3,3-hexafluoro-2-propanol as a solvent. 

In order to improve the properties and the spinnability, fibroin sometimes has been electrospun together with other natural or synthetic polymers (Jin et al., 2002 Park et al., 2004, 2006 Wang et al., 2004, 2006). For instance, Jin et al. (2002) developed an aqueous process for silk electrospinning in combination with PEO. More recently, Cao (2008) used PVA/Silk Fibroin (SF), Gelatin/SF, and Hydroxyapatite (HAP)/SF to produce double-layered (core-shell) nanofibers (mats) by coelectrospinning. 

PVA is also one of the most studied polymers to produce fibers by electrospinning. PVA/CNTs electrospun fibers have first been reported in 2005 (43) and the interaction between PVA and nanotubes in these particular fibers was studied in 2007 (44). A mixture of purified MWNTs and water is sonicated and then added to a PVA solution. The resulting dispersion is electrospun via a voltage of 20 kV. This leads to the production of very thin fibers of typically 300 nm in diameter, as shown in Figure 11.3. 

Figure 11 a). SEM micrographs of P(LLA-CL) fibers electrospun from a polymer concentration of 5wt% at different applied voltage (a) 9 kV (b) 12 kV and (c) 15 kV.b) Relation between fiber diameter and applied voltage in the electrospinning with 5wt% P(LLA-CL) solution [64]. 

J. Ayutsede, M. Gandhi, S. Sukigara, M. Mieklus, H-E. Chen,F. Ko. 2005. Regeneration of Bombyx mori silk by electrospinning. Part 3 characterization of electrospun nonwovenmat. Polymer, 46 pp. 1625-1634. 

The last method to be discussed, which is used to form polymer/ceramic composites by electrospinning, is extremely different to the methods previously described, but worth mentioning. Zuo et al. [129] used a method to create a composite scaffold that is actually the reverse of what most people are doing. Instead of mineralizing the nanofibers, Zuo et al. actually incorporated electrospun polymer nanofibers into a ceramic bone cement in order to form a composite scaffold. It was found that by incorporating electrospun nanofibers into the cement, the scaffold became less brittle and actually behaved similarly to that of a ductile material because of the fibers. Composite scaffolds with different polymers and fiber diameters were then tested in order to determine which scaffold demonstrated the most ideal mechanical properties. However, no cell studies were conducted and this method would most likely be used for a bone substitute instead of for bone regeneration applications. 

Others have combined electrospun scaffolds with scaffolds created by other techniques to create a 3D bone-1 ike scaffold for bone regeneration. For instance, Martins et al. [62] combined both electrospinning and rapid prototyping in order to create a 3D bone-like structure. This method is very similar to the layer-by-layer... 

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