ABSTRACT
I. Introduction .................................................................................................................... 169
II. Clinical Need for Injectable Tissue Engineering Systems ............................................ 169
III. Tissue Engineering Strategies ........................................................................................ 170
IV. The Drive for Injectable Systems .................................................................................. 170
V. In Situ Polymerization ................................................................................................... 172
VI. Thermoresponsive Hydrogels ........................................................................................ 172
VII. Ionic Gels ....................................................................................................................... 173
VIII. Fibrin Glue ..................................................................................................................... 174
IX. Collagen .......................................................................................................................... 175
X. Polyesters ........................................................................................................................ 175
XI. Poly(ethylene Glycol) .................................................................................................... 176
XII. Photopolymerization ...................................................................................................... 176
XIII. Toxicity Study of Photoinitiators .................................................................................. 177
XIV. Cartilage Tissue Engineering with Photopolymerizing Hydrogels ............................... 178
XV. Chondrogenesis of Mesenchymal Stem Cells in a Photopolymerizing Hydrogel ........ 180
XVI. Conclusion ...................................................................................................................... 184
References ................................................................................................................................... 184
The goal of this chapter is to review prior work on the development of injectable hydrogel tissue
engineering systems with a focus on those systems used in conjunction with cells to facilitate the
repair or creation of cartilage. A detailed review of the physical properties of hydrogels is not the
aim of the chapter; however, important considerations will be briefly discussed. More expansive
reviews on the chemistry and physical characteristics of hydrogels already exist in the literature (for
review see Refs. 1,2). The authors will also describe their current research in the area of injectable
tissue engineering systems utilizing photosensitive polymer solutions to create three-dimensional,
cell-laden hydrogel constructs.
