Biomedical applications of electrospinning: Tissue engineering

Electrospinning technique has been available since the first decades of the 20th century, but its applications to tissue engineering or drug delivery are relatively new. This can be attributed to the recent automatization of the technique and its availability. In the last few years, modern electrospinning devices allow the user to control the parameters with high precision and to obtain nanometric fibers [1].

Advances on material science and the precise control of the electrospinning parameters (fiber dimensions and orientation), has permitted to obtain scaffolds with unique properties suitable for vascular, neural, bone or ligament reparations. A critic parameter in electrospinning biomedical applications is the material choice. Both synthetic and natural materials can be used, but also hybrid natural-synthetic compounds. The main requirement of the material is that it must be biocompatible, i.e. it does not induce a harmful effect on the human body. Biocompatible materials can be divided between biodegradable and non-biodegradable materials. The former have the advantage of eliminating a second surgery to remove the implant.

The mechanical properties of the scaffold can be controlled both by the material selection and the electrospinning parameters. Note that, for biodegradable materials, mechanical properties decrease over time [2]. The orientation of the fibers also determines the mechanical properties of the scaffold, as the anisotropy of the material can be modified by using a planar or rotatory collector that orientates the fibers. The degree of anisotropy of the scaffold will depend on the application: For example, to replace highly oriented tissue such as the walls of a native artery, aligned fibers are preferred. I the medial layer of smooth muscle, fibers are aligned circumferentially in order to permit vasoconstriction and vasodilation. [1]

The porosity of the electrospinning fibers determines the ability of the cells to migrate to the scaffold. It is important to note that, according to Eichhorn and Sampson model [3], the thinner the electrospinning fibers are, the smaller is the mean pore radius. Therefore, nanofiber meshes behave as  2D layers on which cells migrate along the surface, rather than 3D structures in which cells can infiltrate.

Finally, the properties of the electrospinning scaffold can be modified by the addition of bioactive molecules to the surface of the fibers, such as peptide sequences, gelatins… This can be used to enhance cell interaction with the scaffold material [4]

Micro-_and_nanofiber_composite_PCL_scaffolds_fabricated_by_electrospinning

Image: electrospinning scaffold [5]

[1] Travis J. Sill, Horst A. von Recum, Electrospinning: Applications in drug delivery and tissue engineering, Biomaterials, Volume 29, Issue 13, 2008, Pages 1989-2006, ISSN 0142-9612

[2] Henry JA, Simonet M, Pandit A, Neuenschwander P. Characterization of a slowly degrading biodegradable polyester-urethane for tissue engineering scaffolds. J Biomed Mater Res A 2007 Sep 1;82(3): 669e79.

[3] Eichhorn SJ, Sampson WW. Statistical geometry of pores and statistics of porous nanofibrous assemblies. J R Soc Interface 2005 Sep 22;2(4):309e18

[4] Dhan B. Khadka, Donald T. Haynie, Protein- and peptide-based electrospun nanofibers in medical biomaterials, Nanomedicine: Nanotechnology, Biology and Medicine, Volume 8, Issue 8, 2012, Pages 1242-1262, ISSN 1549-9634

[5] De Kasper, F.K., Liao, J., Kretlow, J.D., Sikavitsas, V.I., and Mikos, A.G., Flow perfusion culture of mesenchymal stem cells for bone tissue engineering (August 15, 2008), StemBook, ed. The Stem Cell Research Community, StemBook, doi/10.3824/stembook.1.18.1, http://www.stembook.org. – [1] DirectStemBook Figure 1 Micro- and nanofiber composite PCL scaffolds fabricated by electrospinningKasper, F.K., Liao, J., Kretlow, J.D., Sikavitsas, V.I., and Mikos, A.G., Flow perfusion culture of mesenchymal stem cells for bone tissue engineering (August 15, 2008), StemBook, ed. The Stem Cell Research Community, StemBook, doi/10.3824/stembook.1.18.1, http://www.stembook.org., CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=25463830

© Nadetech Innovations 2017

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