Biocompatible chitosan- and starch-based gels for 3D printable inks

Introduction . Carriers intended for cell culture and transplantation are widely used in modern tissue engineering. The creation of inks for printing such media assumes a wide range of variations in their shape and architecture. Chitosan as a natural polymer is increasingly finding application in various fields of regenerative medicine. Chitosan-based scaffolds are an artificial prototype of the extracellular matrix in vitro. The method of 3D printing can be used to bring the structure of such a matrix as close as possible to the properties of native tissues. However, in order to achieve the desired printing quality, the task of developing a chitosan-based ink composition and selecting optimal printing parameters should be solved. Objective. Development of a biocompatible chitosan-based ink with optimal rheological properties suitable for 3D printing. Materials and methods . A bioink was manufactured using the chitosan produced by BiologHeppe (Germany) with a molecular weight of 164 kDa and a deacetylation degree of 92.5%. Starch produced by Merck (Germany) was used to modify the bioink. The method of 3D extrusion bioprinting was used to obtain 3D matrices by a 3D bioprinter by Rockit Invivo (Republic of Korea) equipped with the Android OS software. 3D-printed matrices were obtained from a bioink with different chitosan concentrations: 4% and 6%. Cultures of rabbit mesenchymal stem cells were seeded to study the biocompatibility of the printed structures. Results. The developed chitosan- and starch-based inks demonstrated an increased viscosity of the solution and improved characteristics of the printed designs. The rheological parameters were optimized for printing by increasing the chitosan concentration in the solution up to 6%, as well as by introducing starch at a similar concentration into the solution. An in vitro study also showed the biocompatibility of the printed structures with respect to mesenchymal stromal cells.