Rheology of a hydrogel-ink, printing fidelity and elastic behavior of 3D-printed scaffolds

HERMIDA É.B.; PALMA J.; BERTUOLA M.

Congreso; Cellmat 2020; 2020

German Materials Society (DGM)

Rheology of a hydrogel-ink, printing fidelity and elastic behavior of 3D-printed scaffoldsRecently, 3D bioprinting has emerged as a flexible tool with great potential in various tissue engineering and regenerative medicine applications. Natural hydrogels are widely implemented for this purpose due to their biocompatibility, crosslinking capability and good bioresorption. In this work we studied the printing fidelity and rheological properties of gelatine-alginate-hyaluronic ink, as well as the elastic behavior and cytocompatibility of 3D-printed scaffolds. Ink printability, Pr, was defined as the ratio between the area of pores of a printed grid and the area of the design. Rotary and oscillatory tests were performed at 37°C in a rheometer in the Small Amplitude Oscillatory Shear (SAOS) mode. Creep tests were performed at 41°C, 37°C, 33°C, and 29°C; recorded curves were adjusted with a generalized Kelvin model with two relaxation times; the temperature dependence of these times was fitted by Arrhenius´ law. After crosslinking the 3D-printed with CaCl2 the mechanical response was measured with a Dynamical Mechanical Analyzer. Additionally cytocompatibility were assessed growing DiO labelled NIH/3T3 fibroblasts on printed scaffolds for 48h.Inks depicted a pseudoplastic behavior with thermo-responsive gelation point of gelatine at 25°C, leading to self supported structures during 3D-printing and good printing fidelity (Pr=0.91±0.06). During the 3D-printing process the ink cartridge was at 37°C for and the plate at room temperature. The height of the extruded filament, measured as a function of time, was compared with the equation that predicts the creep at different temperatures. This prediction was significantly similar to height measurements.Mechanical characterization of scaffolds evidenced a tensile module of (0.13±0.01 MPa). Fibroblast cells could attach and grow on the surface of scaffolds, revealing cytocompatibility of final products. Herein reported self-supported 3D-printed scaffolds could be considered for soft tissues regeneration, such as skin, muscle and endothelium, taking into account their elastic modulus and their cytocompatibility.