ECM Based Bioink for Tissue Mimetic 3D Bioprinting.

To create tissue replacements with qualities similar to human tissues, and for ease of tissue loss repair, novel 3D printing fabrication methods have recently been introduced and popularized in the field of tissue engineering and regenerative medicine as an alternative to the scaffold fabrication methods. 3D printing may provide the fabricate process to better mimic the internal microstructure and external appearance. Printable bioink should be developed for stable 3D structure stratification. Advanced bioinks for 3D printing are rationally designed materials intended to improve the functionality of printed tissue scaffolds. The search for an appropriate bioink capable of providing a suitable microenvironment to support cellular activities is ongoing. The extracellular matrix (ECM) provides instructive cues for cell attachment, proliferation, differentiation, and ultimately tissue regeneration. The use of ECM-based biomaterials in regenerative medicine is therefore, rapidly expanding. In this respect, the decellularized ECM biomaterials have gained popularity as an excellent source of bioink, given its capability to inherit the intrinsic cues from a native ECM. In this chapter, we describe the current status of ECM-based biomaterials, the emerging trends in ECM bioink development, and bioink requirements that could enable proper selection of the bioink to fabricate an engineered tissue/organ. In particular, rheological properties of bioprinting materials are significant for printing resolution and shape fidelity. We propose a general method of measuring non-Newtonian rheological properties based on rotational rheometers in oscillatory mode. In addition, the mathematical modeling incorporating the power law model is discussed. These approaches can be easily used to optimize printing parameters and verify the bioink printability because a variety of dECM-based bioinks possess shear-thinning properties.