Electrospun scaffolds limitations

Early reports on electrospun scaffolds described poor cellular infiltration [175], Frequently, cells adhered at the surface and thus coated the nano- or submicrometer-scaled electrospun meshes due to the small pore size. In order to overcome this limitation, pore sizes were increased by combining ES with other methods. These approaches included the coating of microfibers with nanofibers [183], Other strategies combine ES with leaching [184, 185], freeze-drying [186], blowing agents [187], or ice templates [188],... 

The pore size of an electrospun scaffold will essentially dictate whether it is viewed as a 2-dimensional mat or a 3-dimensional scaffold by cells. Depending on the application either might be desirable. Additionally, the ability to engineer scaffolds with a desired pore size distribution may allow for the use of nanofibrous scaffolds without limiting cell infiltration, combining the advantages of both micro-and nanofibrous scaffolds. 

This chapter will discuss electrospinning as a promising fabrication technique for scaffolding, current applications of electrospun scaffolds for cartilage tissue engineering, as well as limitations with the use of such scaffolds for translational applications. 

Overall, electrospinning finds a great utility in the fabrication of in vitro cell culture systems and in vivo tissue-engineering scaffolds. However, there are still limitations and drawbacks that need to be overcome to further enhance therapeutic applications of electrospun scaffolds in cartilage regeneration. 

Current limitations of electrospun scaffolds in cartilage tissue engineering... 

Gluck JM, Rahgozar P, Ingle NP, Rofail F, Petrosian A, Cline MG, et al. Hybrid coaxial electrospun nanofibrous scaffolds with limited immnnological response created for tissue engineering. J Biomed Mater Res B Appl Biomater 2011 99B 180-90. 

Tubular scaffolds fabricated by electrospinning have been extensively studied as scaffolds for small diameter (<6 mm) vascular grafts. Current artificial grafts, mainly Dacron and expanded polytetrafluoroethylene (ePTFE), have had some success when used in larger diameter grafts but are limited by issues such as thrombosis when considered for use in smaller diameter grafts. Electrospun tubular scaffolds can be fabricated with well-controlled diameters and uniform thickness across the material. The variety of polymers from which these scaffolds can be synthesised has resulted in scaffolds with mechanical properties similar to those of native vascular tissues, and hence these better support blood flow and capillaiy in-growth. 

Despite such advantages, electrospun silk fibroin scaffolds are still limited as bone tissue replacement due to their low mechanical strengths. The enhancement of the mechanical strength has been demonstrated by incorporating inorganic ceramics into pol5miers. 

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