Decellularized extracellular matrix as bioink for 3D printing : Printability assessment of new dECM hydrogel formulation

3D bioprinting is a prominent field within tissue engineering, with potential for construction of complex structures mimicking physiological properties of human tissue. Bioinks are a crucial part to achieve precise tissue engineering and enabling cell viability. To achieve 3D bioprinting the bioink needs to attain characteristics that allow for printing, retaining shape and cells being able to survive and adapt to the environment present in the printed construct. Over the years, different materials have been proposed as bioink, including naturally derived polymers, natural polymers as well as synthetic polymers, though coming with several drawbacks including lack of interaction between cells and matrix. With help from different chemical, physical or mechanical processes, these materials have been able to mimic the physiological processes in mammals. In the field of natural polymers, decellularized extracellular matrix (dECM), derived from tissue extracellular matrix through decellularization, emerges as a promising candidate. Through decellularization, ECM's structural and compositional integrity remains intact while cellular components are removed, thus providing cells with a physiological 3D environment. However, 3D bioprinting of dECM remains challenging, due to low storage modulus of the hydrogel and slow gelation time, only a few studies report the use of dECM hydrogels as bioinks. In this report, porcine skin derived dECM was used to form a hydrogel for evaluation in terms of rheological characteristics: viscosity, storage modulus and loss modulus in combination with a printability assessment: examining extrudability, shape fidelity and uniformity and, as well as the gelation and reversibility factors. Evaluation of previously mentioned factors was conducted on a set of concentrations of dECM in the hydrogel, these different concentrations were achieved by dilution using phosphate saline buffer (PBS). Concentrations examined in this study were of the lower variety starting with 5 mg dECM.mL-1 and ...