The main purpose of the present study has been the investigation of composite microfibers produced with the combined use of alginate and extracellular matrix (ECM) derived components for bone tissue engineering. We investigated the feasibility to build up novel bio-inspired materials, in which a hydrogel based scaffold is coupled to an ECM component derived from urinary bladder matrix (UBM) or from collagen (gelatin). The combined use of alginate based microfibers produced by a highly controlled microfluidic procedure, modified through the addition of UBM microflakes or gelatin powder, led to bioadhesive hydrogels, whose architecture, constitutive features and dimensions were investigated with respect to their role on the osteogenic potential of SaOS-2 osteoblastic-like embedded cells. The microfluidic procedure allowed a precise control of the dimensional and morphological characteristics of the microfibers, favourable influencing the viability and function of the embedded cells. Notably, the use of a two inlets micromixing chip resulted in an even distribution of cells and other constituents within the entire volume of the microfibre. We demonstrated that the combined utilisation of alginate (representing the main component of the device) and gelatin solution or UBM particles resulted in a synergistic activity of both materials, positively influencing the viability and 3D colonisation of the embedded cells. Moreover, the bimodal nature of the microfibers provided the ideal environment for the deposition of biomineralised particles as proved by the intense Alizarin Red staining evidenced in relatively short culture time (i. e. 7 days). In this respect, the engineered microfibers represent a smart scaffold offering: (a) the mechanical and material properties of alginate, which can be in turn varied through different gelling conditions such as diverse divalent cations, and (b) the bioactive function given by the presence of gelatin and UBM, improving the viability and osteogenic potential of the embedded cells.
Disclosure: The authors declared no competing interests.