Polyurethane in bone tissue engineering: 3D-Bioprinting Vs. electrospinning

Bone injuries caused by trauma or disease affect millions of people around the world. Although bone fixation, allographs, and autographs are established procedures for addressing bone injuries, their applications are subject to subsequent surgical removal, risk of disease transmission, or danger of morbidity associated with healing. To overcome these limits, bone tissue engineering employs a temporary matrix or scaffold to repair and restore damaged bone. Various biomaterials have been used for bone tissue engineering, and polyurethane has superior mechanical properties compared to other biomaterials. Electrospinning and bioprinting are gaining much interest in bone tissue engineering. These manufacturing methods can provide excellent control over the geometry and porosity of the scaffolds, which would give tunability in cell viability and growth. The review article examines recent publications on the use of 3D bioprinted and electrospun polyurethane scaffolds for bone tissue engineering and their advantages. Some of these advantages include creating optimal microenvironments for cell adhesion and proliferation, offering a wide range of sizes and mechanical properties that enable personalized scaffolds based on the size and location of bone injuries and defects, and the ability to incorporate osteoinductive and osteogenic agents into the scaffold structure. Also, this review identifies knowledge gaps, such as cell-loaded polyurethane bioinks due to their non-hydrogel structure or lack of 3D cell culture in electrospun scaffolds, and suggests future research directions in the field.