Promoting epithelium regeneration for esophageal tissue engineering through basement membrane reconstitution

Scaffolds mimicking hierarchical features of native extracellular matrices may facilitate cell growth and anatomical tissue regeneration. In our previous study, esophageal basement membrane (BM) was shown to be composed of interwoven fibers with mean diameter of 66 ± 24 nm (range 28-165 nm) and with abundant pores of unequal sizes. The main extracellular matrix (ECM) contents found in porcine esophageal BM were collagen IV, laminin, entactin, and proteoglycans. In this work, biodegradable polycaprolactone (PCL) and silk fibroin (SF) were spun with electrospinning technology, both individually and in combination, to fabricate fibrous scaffolds with diameters between 64 and 200 nm. The surface morphologies of PCL, PCL/SF, and SF scaffolds were observed under scanning electron microscopy. Their mechanical properties were tested and the cytocompatibility was evaluated in vitro via culture of primary epithelial cells (ECs). The SF or PCL/SF scaffold favorably promoted epithelial cell attachment and proliferation comparing with PCL scaffold. However, mitochondrial activity of epithelial cells was greatly promoted when major BM proteins were coated onto the electrospun scaffold to provide an ECM-like structure. Results from in vivo tests revealed that the electrospun scaffolds coated with BM protein possess good biocompatibility and capability to promote epithelium regeneration.