Electrospun multiscale fibrous scaffolds for tissue engineering

Abstract

The use of Electrospun ECM-mimicking nano fibrous scaffolds for tissue engineering is limited by poor cellular infiltration. We hypothesized that cell penetration could be enhanced in scaffolds by using a hierarchical structure where nano fibers are combined with micron-scale fibers while preserving the overall scaffold architecture. To assess this, we fabricated electrospun poly(caprolactone) (PCL) and porous poly(lactic acid) (PLA) scaffolds having nanoscale, microscale and combined micro/nano architecture with and without nano-Hydroxy Apatite (nHAp). All the scaffolds were evaluated for its spectroscopic, morphological, mechanical, thermal, cell attachment and protein adsorption properties. The cell activity, proliferation and total protein adsorption on the nanofibers/ nano-fibers with nHAp was significantly higher than on the micro-fibers although the adsorption per unit area was less on the nano-fibers due to the much higher surface area of nano-fibers. Though the bioactivity was intermediate to that for nanofiber and microfiber scaffold, a unique result of this study was that the micro/nano combined fibrous scaffold showed improved cell infiltration and distribution than the nanofibrous scaffold. While the cells were found to be lining the scaffold periphery in the case of nanofibrous scaffold, micro/nano scaffolds had cells dispersed throughout the scaffold. Further, as expected, the addition of nanoparticles of HAp improved the bioactivity though it did not play a significant role in cell penetration. Thus, this strategy of creating a 3D micro/nano architecture, which would increase the porosity of the fibrous scaffold and thereby improving the cell penetration, can be utilized for the generation of functional tissue engineered constructs in vitro.In the second part of the study, we discussed in detail about the development of tubular scaffolds for vascular tissue engineering.