Collagen obtaining for 3D printing to create biological substitutes for biomedical applications
Biodegradable scaffolds with three-dimensional porous structure are fundamental components for tissue engineering, on which cell cultures are grown to create biological substitutes that restore or repair tissue or organ damage. Collagen is the main protein of the human extracellular matrix, its structure allows the union, migration and in several cases, cell differentiation; leading it to be one of the most studied material for the development of biomedical scaffolds. However, its use to fabricate reproducible and pore-structure-controlled 3D structures, which are designed to stimulate cell adhesion and subsequent migration, and the easy diffusion of nutrients, has been limited due to its low processability by the means of layer-by-layer technologies. In the present, we propose three-dimensional impression for obtaining highly porous collagen scaffolds for biomedical use.
A simple and economical method is developed for collagen purification starting from porcine skin through treatments with acidic and salt solutions, which preserve the structure of the fibers unlike normally used enzymatic procedures which denature the protein. Characterization and quantification through spectrophotometry and denaturing electrophoresis allowed to verify the effectiveness of this method for obtaining highly pure type I collagen; and rheometric studies indicated the viscosity of the material was suitable for 3D printing applications. A collagen bioink was prepared, which presented appropriated viscosity and stability for printing complex-structured 3D scaffolds with an extrusion bioprinter. A physical characterization of the printed scaffolds was performed through porosity and water swelling assays and cytocompatibility according to the ISO Standard 10993, part 5-2009, indicating that they aren’t cytotoxic, as it is show in this work. This leaves the door open for subsequent studies oriented to cell culture experiments and in vivo analysis with the collagen printed scaffolds.