ABSTRACT
The musculoskeletal system denes the major structure of the body, and enables the whole body to move, stabilize itself, and maintain its form and function in load-bearing conditions. The major components of the musculoskeletal system are bone, cartilage, muscle, tendon, and ligaments. The mechanical and biochemical properties of these tissues are vital to the function of the system. Current clinical practice on repairing orthopedic tissue
CONTENTS
Introduction ......................................................................................................... 191 Scaffolds ................................................................................................................ 192
Engineering Functional Materials ................................................................ 195 Hydrogels ........................................................................................................ 197 Environmentally Responsive Hydrogels .................................................... 198
Cells. ......................................................................................................................200 Adipose-Derived Stem Cells ........................................................................200 Induced Pluripotent Stem Cells ................................................................... 201 Cell Homing .................................................................................................... 201
Instructive Signals ............................................................................................... 203 Synergistic Delivery ....................................................................................... 204 DNA Delivery ................................................................................................. 205 siRNA Delivery ............................................................................................... 206
Technology for Manufacturing Tissue Engineering Scaffolds ...................... 207 Polymerization ................................................................................................ 208 Microfabrication Platforms ........................................................................... 208 Supercritical CO2 and Gas-foamed Scaffolds ............................................. 211 Self-Assembly from Amphiphilic Peptide .................................................. 213 Electrospun Nanobers ................................................................................. 215
Conclusions .......................................................................................................... 215 References ............................................................................................................. 216
loss relies mostly on metallic implants such as total hip replacement. While effective, these approaches provide only mechanical support and do not mimic biological tissue structure and functions. Successful musculoskeletal tissue engineering requires a good understanding of the structural materials of specic tissues, which are organized in a hierarchical manner. Bones are composed of a central marrow canal surrounded by a bi-layer of trabecular and compact bone encased in an outer periosteum. Trabecular bone contains a tightly woven network of hydroxyapatite and type I collagen bers, which are composed of tropocollagen units formed by polypeptide helices. All tissues in the musculoskeletal system contain a similar type of hierarchy that denes the diverse tissue structure and functions in our body. The interactions between cells, matrix networks, and biological signals are crucial for the normal tissue structure and function, and disruptions in these processes often lead to musculoskeletal diseases and/or tissue degeneration. Loss of musculoskeletal tissues is common and may be caused by traumatic injury, aging, diseases, or unhealthy lifestyle choices such as alcohol abuse. While our body can regenerate minor injury, guided regeneration is required where the defect size is beyond the self-healing capabilities of the body.
