Electrospinning

The process of electrospinning, which has been well known for many years in the textile industry and in organic polymer science [48-50], has recently emerged as a novel tool for generating biopolymer scaffolding for tissue engineering [51]. This is a process for the production of polymer filaments using an electrostatic force

[52, 53]. In this process, a polymer solution is introduced into the electrical field generated by a high-voltage power supply. The polymer filaments are formed from the solution traveling between two electrodes bearing electrical charges of opposite polarity. Upon ejection from a metal spinneret through a small hole, the solvent in the charged solution jet rapidly evaporates, thus generating ultrathin fibers, which then are deposited onto the collector [54]. Optimization of this technique depends to a large part on the material to be electrospun, and involves adjusting crucial parameters, such as the nature of the solvent and the concentration of the solute, as well as the potential difference and the distance between the electrodes [9]. Electrospinning is a novel, increasingly important platform technology for producing nanofibrous scaffolds from a variety of polymer materials, including synthetic polymers, natural proteins, and blends of natural and synthetic materials [9, 35, 55]. Figure 1.1 illustrates typical (autofluorescent) light-microscopic images of electrospun elastin (Fig. 1.1A) and gelatin (Fig. 1.1B), as well as scanning electron microscopy (SEM) images of PLGA (1.1C), and a blend of PANi-gelatin fibers (Fig. 1.1D).

The topology of these electrospun scaffolds closely mimics that of the native ECM; it is particularly striking in the case of the wavy appearance of elastin, reminiscent of the elastic lamina in blood vessels. Depending on the spinning conditions, fibers with diameters in the range from several micrometers to less

Fig. 1.1 Typical images of scaffolds for tissue engineering.

Electrospun elastin (A) and gelatin (B) fibers. Scanning electron microscopy micrographs of electrospun PLGA (C) and PANi-gelatin (D) fibers.

Fig. 1.1 Typical images of scaffolds for tissue engineering.

Electrospun elastin (A) and gelatin (B) fibers. Scanning electron microscopy micrographs of electrospun PLGA (C) and PANi-gelatin (D) fibers.

than 100 nm are obtained. These fibrous scaffolds have a very high surface area to mass ratio, and can be electrospun into 3D scaffolds with very high porosity. These biomimetic matrices facilitate cell attachment, support cell growth, and regulate cell differentiation [56].

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