Chapter 11 - Nanoapatitic composite scaffolds for stem cell delivery and bone tissue engineering

Abstract

The need for bone defect repair and regeneration arises from trauma, disease, congenital deformity, and tumor resection. Bone fracture occurs to 7 million people each year in the United States, and musculoskeletal conditions cost $215 billion annually. An important approach for bone tissue engineering involves the use of three-dimensional scaffolds with cells guided for osteogenesis. This chapter describes a new class of self-setting, mechanically strong, and biomimetic nanoapatite scaffolds for stem cell delivery and bone tissue engineering. Self-setting calcium phosphate cement was used as the matrix material. Strong and macroporous scaffolds were developed via absorbable fibers, collagen, biopolymer chitosan, and mannitol porogens. The macroporous scaffolds were suitable for cell infiltration, and the nanoapatite crystals and the collagen fibers enhanced osteoblastic cell attachment. Resistance of the new scaffolds to fracture and cyclic fatigue were greatly increased rendering the scaffolds promising for a wide range of moderate load-bearing dental, craniofacial, and orthopedic repairs. The nanoapatitic scaffolds showed excellent biocompatibility with stem cells. Human umbilical cord mesenchymal stem cells and bone marrow mesenchymal stem cells attached to these scaffolds, proliferated, and differentiated down the osteogenic lineage. The nanoapatite–fiber scaffold morphologically mimicked the extracellular matrix of natural bone, and supported stem cell attachment and function. Potential applications of this new class of nanoapatitic scaffold/stem cell constructs include the major reconstructions of the maxilla, mandible, and other craniofacial restorations, bone regeneration after trauma or tumor resection, in situ fracture fixation, and filling and strengthening osteoporotic bone lesions at risk for fracture.