# Electrospun Nanofibrous Membranes for Tissue Engineering and Cell Growth
## 7 Pcl  
PCL was reported in the previous sections as an often used blend partner for different polymers. The material is sometimes used to prepare pure electrospun nanofiber mats for tissue engineering [106, 107, 108]; however, in many cases blends are produced to combine the advantages of two or more materials.  
Combining PCL with PLGA, [PERSON] and [PERSON] used electrospinning to prepare nanofiber mats [109]. They found an increasing biocompatibility with increasing amount of PLGA in the blend, and it even showed a higher proliferation than on common tissue culture plates. This was attributed to the PLGA support in the PCL nanofiber mats, which apparently increased biocompatibility, cell attachment, and proliferation. In addition, the blended nanofiber mats showed higher mechanical strength than pure PCL.  
To reach a higher biodegradation of a PCL nanofiber mat, [PERSON] et al. blended it with poly(\(N\)-vinyl-2-pyrrolidone) (PVP), which could be washed out in cell culture medium, resulting in nanoporous fibers [110]. This nanoporosity, not only supported biodegradation, but also the attachment and spreading of adipose derived stem cells (ADSCs). The finding that the number of elongated cells decreased with increasing PVP content was explained by changes in the cytoskeletal organization influencing the cell response and the chemical composition, as well as morphology, of the substrate affecting the cytoskeletal organization.  
For bone tissue engineering, [PERSON] et al. used PCL nanofiber mats with embedded octacalcium phosphate (OCP) particles [111]. On the one hand, the average fiber diameter was significantly reduced by adding OCP, which was attributed to the increased solution conductivity during electrospinning, as a result of the additional OCP particles. This was correlated with a slight increase in the ultimate tensile stress, strain, and Young's modulus. Moreover, PCL/OCP was found to form a hydroxyapatite layer on its surface when soaked in simulated body fluid (SBF). Seeding human osteoblast cells on the scaffold showed a positive influence of OCP on their growth due to both these factors.  
On the other hand, [PERSON] et al. combined PCL with zein and gum arabic to prepare skin tissue engineering scaffolds [112]. They found an increase in fibroblast proliferation, as compared to tissue culture polystyrene, due to the improved hydrophilic properties and functional groups of zein and gum arabicum, but also a slightly reduced viability, as compared to the reference sample. In addition, antibacterial properties against _E. coli_ were found, due to the antibacterial properties of the gum arabic. These antibacterial properties could be further increased by adding _Calendula officinalis_ extract in different ways to the nanofiber mats [113].  
[PERSON] et al. produced electrospun PCL/poly(glycerol-sebacate) (PGS) nanofiber mats with diverse PCL/PGS ratios and additional bioactive glass particles [114]. PGS increased the average fiber diameter as compared to pure PCL nanofiber mats, while biogas increased this value's standard deviation, but not the mean value. Release of biogas particles was found for all composite nanofiber mats, making them usable for therapeutic ion release. When seeding a stromal cell line onto these substrates, however, PGS was found to reduce cell viability (samples S1-S4 in Figure 5) as compared to pure PCL, with or without bioglass (samples S5-S7 in Figure 5), which was attributed to PGS degradation from the nanofiber surface, thus reducing the cell adhesion capability.