Bone Tissue Engineering Scaffolds for Bone Aging: Drug Delivery and Microenvironment Regulation.

Aging is a gradual process leading to the decline of physiological functions across cells, organs, tissues, systems, and the surrounding microenvironment, particularly affecting the musculoskeletal system. Bone aging often presents with osteoporosis and impaired osteogenic niche, thereby increasing fracture risk and decreasing regenerative capacity. Therefore, bone aging and osteoporotic bone defects have become a significant challenge in clinical practice. Tissue-engineered scaffolds are of significant importance in managing osteoporotic bone defects by providing mechanical support, facilitating bone regeneration and repair. They can also serve as a vehicle for drugs or factors for osteoporosis management, thereby enabling localized targeted therapy. The local release of active pharmaceutical agents for the treatment of osteoporosis via biomaterials could serve to reduce the occurrence of systemic side effects, while improving the local aging metabolic microenvironment and immune microenvironment. This review presents a comprehensive discussion of the mechanisms and treatment methods of osteoporosis. The scaffolds used for osteoporotic bone defects are also reviewed. We conducted an in-depth analysis of the impact of diverse preparation techniques and modifications on the osteogenic properties of the scaffolds, and reviewed different materials of drug delivery scaffolds for the repair of osteoporotic bone defects. Finally, we put forward our scientific concept regarding the treatment of bone aging and osteoporotic bone defects. We hope to provide a theoretical basis and research ideas for further in-depth studies on treating osteoporosis and bone aging.