Injectable hydrogels for bone and cartilage repair.

Injectable in situ crosslinkable gels are highly desirable clinically as they can be introduced into a body via a minimally invasive manner using endoscopic or percutaneous procedures. Several hydrophilic polymeric systems that respond to stimuli such as light, temperature, pH, ionic concentration as well as those that can undergo chemical reactions to form crosslinked matrices are currently under development. This paper discusses the applications of hydrogels as scaffolds to mimic the native extracellular matrix of bone and cartilage. A comprehensive description of various gelation methods used in hydrogel preparation and their application as injectable cell and protein delivery vehicle for bone and cartilage regeneration is also presented.