Advances in Porous Scaffold Design for Bone and Cartilage Tissue Engineering and Regeneration

Tissue engineering of bone and cartilage has progressed from simple to sophisticated materials with defined porosity, surface features, and the ability to deliver biological factors. To avoid eliciting a foreign body response due to inclusion of allogeneic cells, advances in functional scaffold design harness the endogenous ability of the body to regenerate. We review advancements in the surface and structural properties of typical polymeric, ceramic, and metallic scaffolds for orthopedic use. First, we provide an overview of methods and materials, with a focus on additive manufacturing and electrospinning. Multidimensional physical properties of scaffolds, including three-dimensional macrostructure, pore design, and two-dimensional hierarchical surface roughness, allow tissue regeneration at different spatial and temporal scales. Enhanced biological response can be achieved through surface functionalization and the use of exogenous factors. Finally, different in vitro and in vivo models are discussed for translation of these technologies for clinical use. Challenges in musculoskeletal tissue regeneration affect millions of patients globally. Scaffolds for tissue engineering bone and cartilage provide promising solutions that increase healing and decrease need for complicated surgical procedures. Porous scaffolds have emerged as an attractive alternative to traditional scaffolds. However, the success of advanced materials, use of biological factors, and manufacturing techniques can vary depending on use case. This review provides perspective on porous scaffold manufacturing, characterization and application, and can be used to inform future scaffold design.