No abstract

biodegradable polymer scaffolds were widely studied for bone regeneration because the metal implants have the limitations of non-degradability and high rigidity. [2,3] Common methods for fabricating such a scaffold include particulate leaching, electrospinning, and freeze-drying. However, these methods have limited reproducibility and versatility in their manufacturing processes. [4] To solve these problems, the 3D bioprinting technology for making scaffolds by stacking printing materials has been applied. [5] This 3D bioprinting technology can control the architecture of fabricated structures, so that it only comprises interconnected networks, and also controls the shape of the scaffold. Interconnected pores are an important component of tissue engineering scaffolds because they play roles in cell viability, migration, proliferation, and differentiation. [6] In addition, reproducibility can be guaranteed by bioprinting. β-tri-calcium phosphate (β-TCP) is known to form new bone with osteoconductive properties and are widely applied for bone regeneration. The solubility of β-TCP is higher than that of hydroxyapatite, so it forms higher-density aggregates to bone defects, thereby promoting bone formation. [7,8] Gelatin, a natural polymer derived from partially hydrolyzed collagen, has biological properties such as biocompatibility and 3D printed scaffolds composed of gelatin and β-tri-calcium phosphate (β-TCP) as a biomimetic bone material are fabricated, thereby providing an environment appropriate for bone regeneration. The Ca 2+ in β-TCP and COO − in gelatin form a stable electrostatic interaction, and the composite scaffold shows suitable rheological properties for bioprinting. The gelatin/β-TCP scaffold is crosslinked with glutaraldehyde vapor and unreacted aldehyde groups which can cause toxicity to cells is removed by a glycine washing. The stable binding of the hydrogel is revealed as a result of FTIR and degradation rate. It is confirmed that the composite scaffold has compressive strength similar to that of cancellous bone and 60 wt% β-TCP groups containing 40 wt% gelatin have good cellular activity with preosteoblasts. Also, in the animal experiments, the gelatin/β-TCP scaffold confirms to induce bone formation without any inflammatory responses. This study suggests that these fabricated scaffolds can serve as a potential bone substitute for bone regeneration.

Scaffold porosity has played a key role in bone tissue engineering aimed at effective tissue regeneration, by promoting cell attachment, proliferation, and osteogenic differentiation for new bone formation.