Effect of electrospun fiber diameter and alignement on macrophage activation and secretion of proinflammatory cytokines and chemokines

Medical devices and tissue engineered constructs may induce an inflammatory reaction – termed foreign body reaction (FBR) – after their in vivo implantation. Despite recent advances in material science and tissue engineering, current knowledge of the inflammatory mechanisms associated with FBR remains scanty. Electrospinning has been recognized as a scaffold fabrication technique with great potential. From a wide range of polymer solutions and melts, this technique produces continuous polymeric fibers with diameters ranging from a few nanometers to tens of microns. The possibility of controlling fiber morphology and fiber deposition pattern makes electrospinning a powerful method to fabricate tissue engineered scaffolds with a defined micro/nano-architecture in terms of fiber size and fiber orientation. Accordingly, lectrospun substrates have been used for a wide range of tissue engineering applications including neural, ardiovascular, bone, and skin tissue engineering. Despite the increased interest in electrospinning, the potential effects of electrospun scaffolds on the immune system have not been fully examined. Macrophage activation can be modulated by biomaterial topography according to the biological scale (micrometric and nanometric range). In this study we investigated the effect of fiber diameter and fiber alignment of electrospun poly(L-lactic) (PLLA) scaffolds on macrophage RAW 264.7 activation and secretion of proinflammatory cytokines and chemokines at 24 h and 7 days.