Fabrication of anisotropic collagen-based substrates for potential use in tissue engineering

Abstract

Stimuli-responsive nanomaterials have the prospective to enable the fabrication of new extracellular matrix-like substrates with unique structures and cell-instructive capabilities. The development of biocompatible collagen substrates with on-demand ordered architectures is an open challenge since it is well-known that the directionality of the collagen fibres affects important cell behaviour, such as proliferation, differentiation, and ultimately, tissue regeneration. Here, an easy and cheap approach to fabricate anisotropic collagen-based substrates exhibiting cells-instructing ability was proposed. Paramagnetic iron oxide nanoparticles (IOPs) coated with polyethylene glycol were synthetized by a coprecipitation and solvothermic method and mixed with a collagen precursors solution. The suspension was then immersed within a static and low-intensity magnetic field to trigger the IOPs self-assembly. Guided by the external stimulus, IOPs assembled along the magnetic field lines into long filamentous structures within the collagen matrix. The solidification of the pre-cursors solution in the presence of filamentous IOPs’ structures promotes the collagen organization into ordered fashions. The obtained collagen substrate demonstrated good cytocompatibility and cells’ instructive properties.