Biomimetic and bioactive nanofibrous scaffolds from electrospun composite nanofibers

Abstract

Electrospinning is an enabling technology that can architecturally (in terms of geometry, morphology or topography) and biochemically fabricate engineered cellular scaffolds that mimic the native extracellular matrix (ECM). This is especially important and forms one of the essential paradigms in the area of tissue engineering. While biomimesis of the physical dimensions of native ECM's major constituents (eg, collagen) is no longer a fabrication-related challenge in tissue engineering research, conveying bioactivity to electrospun nanofibrous structures will determine the efficiency of utilizing electrospun nanofibers for regenerating biologically functional tissues. This can certainly be achieved through developing composite nanofibers. This article gives a brief overview on the current development and application status of employing electrospun composite nanofibers for constructing biomimetic and bioactive tissue scaffolds. Considering that composites consist of at least two material components and phases, this review details three different configurations of nanofibrous composite structures by using hybridizing basic binary material systems as example. These are components blended composite nanofiber, core-shell structured composite nanofiber, and nanofibrous mingled structure.

Figure 1

Schematic cross-sectional views of different structures of composite nanofibers from components of A and B. (a) randomly blended; (b) core-shell structured; and (c) nanofibers-mingled (from concurrent electrospinning).

Figure 2

SEM images of 3-D porous fibers (a) after gelatin was leached out of the electrospun Gt/PCL composite fibers (b) (Zhang, Feng et al 2006). Scale bar 2 μm.

Figure 3

Illustrated cross-sectional views of a variety of novel and functional polymeric nanofibers from coaxial electrospinning, including basic bi-component nanofiber, surface coated/modified nanofiber through tuning the sheath thickness, nanoparticles encapsulated nanocomposite nanofiber, and hollow nanofibers where the core component is removed.

Figure 4

Coaxial electrospinning were employed to develop core-shell nanofibers (a) (Zhang, Huang et al 2004), self-assembled FePt magnetic nanoparticles (ca. 4 nm) encapsulated nanofibers (b) (Song, Zhang et al 2005), hollow nanofibers (c) (Li and Xia 2004), and multichannel tubes (d) (Zhao, Cao et al 2007).

Figure 5

Core-shell structured collagen-r-PCL nanofibers favored HDFs proliferation (a) and cellular infiltration (b) (Zhang, Venugopal et al 2005).

Figure 6

Schematic illustration showing the formation of larger pores by electrospinning of mingled nanofibers and in situ leaching out of the water soluble nanofibers (red lines) during cell cultivation (Zhang 2004).

Figure 7

Confocal laser scanning micrographs of electrospun mingled fibrous structure of SPU/PEO. (a) Bottom region of the mixed fiber mesh. SPU and PEO were stained with rhodamine and FITC, respectively. (b) Middle region of the mesh observed at the 4 μm-upper region than (a). (c) Top region of the mesh observed at the 4 μm-upper region than (b) (Kidoaki, Kwon et al 2005). Scale bar 10 μm