Suitability of silk-based 3D biotextiles seeded with human adipose-derived stem cells for a bone tissue engineering approach

摘要

Human Adipose-derived Stem Cells (hASCs) became an emerging possibilityfor tissue replacement therapies, such as bone tissue regeneration.Due to their osteogenic differentiation potential, easy isolation,expansion and in vitro proliferation, they have become a highly potentialsource of seed cells to be seeded in bone tissue engineering (TE)constructs and have demonstrated promising prospects in bone regeneration[1, 2]. To date several strategies have been proposed with moreor less success to prepare porous three-dimensional biodegradable scaffoldsfor bone TE. Among them, textile technologies are particularlyinteresting since they can allow for producing finely tuned, fibre-basedcomplex structures, offering superior control over the design (ex: size,shape, porosity, fibre alignment), manufacturing and reproducibility.The aim of this work is to evaluate the potential of recently developedsilk-based biotextile structures [3] to promote hASCs adhesion, proliferationand osteoblastic differentiation. Natural silk yarns were processedinto different 3D structures using standard knitting or warpknittingtechnologies to increase the scaffold’s tridimensionality. In thelatter case two knitted silk layers are assembled and spaced by a monofilamentof polyethylene terephthalate (PET). These constructs werecharacterized in terms of their morphology by Microcomputed Tomography(l-CT) and scanning electron microscopy (SEM). The mechanicalproperties were investigated through compressive tests anddynamic mechanical analysis (DMA). All constructs disclose a biocompatiblebehavior, assessed using a mouse fibroblastic cell line (L929;ECACC, UK). hASCs were seeded onto the scaffolds and cultured for14, 21 and 28 days in osteogenic medium. All textile constructs wereanalysed in terms of cell adhesion, proliferation and differentiationpotential influence through the biological assays, alkaline phosphatase(ALP), DNA and Ca2+ quantification and histological, confocal, SEMand Real-Time PCR analysis. The obtained constructs present veryreproducible intra-architectural scaffold geometry with high surfacearea and exhibiting a wide range of porosities. By the above mentionedassays it was possible validate the developed constructs as suitable forhASCs adhesion, proliferation and differentiation into an osteoblasticlineage. The positive influence of the developed 2D/3D textile structureson the osteoblastic differentiation potential of hACSs is an importantoutcome that validates future bone tissue enginnering approachesusing these fibre-based architectures.