ABSTRACT
I. Introduction ...................................................................................................................... 71
II. Photopolymerization Mechanisms ................................................................................... 72
A. Photoinitiation .......................................................................................................... 72
1. Types of Initiators ............................................................................................. 73
2. Rate of Initiation ............................................................................................... 74
B. Propagation and Termination ................................................................................... 75
C. Advantages/Disadvantages ....................................................................................... 76
III. Multifunctional Macromers ............................................................................................. 76
A. Types of Materials ................................................................................................... 76
B. Cross-Linking Mechanism ....................................................................................... 78
C. Macromer Properties ................................................................................................ 79
D. Degradation Mechanisms ......................................................................................... 79
IV. Hydrogel Properties and Characterization ....................................................................... 80
A. Equilibrium Swelling Ratio ..................................................................................... 80
B. Gel Mechanics .......................................................................................................... 81
C. Cross-Linking Density ............................................................................................. 81
D. Transport Properties ................................................................................................. 82
E. Mass Loss and Degradation ..................................................................................... 83
V. Cell Encapsulation ........................................................................................................... 85
VI. Applications ...................................................................................................................... 86
A. Tissue Engineering ................................................................................................... 86
B. Drug Delivery ........................................................................................................... 87
References ..................................................................................................................................... 87
Further Reading ............................................................................................................................ 90
Photopolymerization reactions have been explored since the times of the ancient Egyptians who
used sunlight to cross-link linens during mummification. Since then, photopolymerizations have
been utilized in a diverse array of applications ranging from high-tech integrated circuits to printing
plates for newspapers to polymeric dental fillings. The versatility of photopolymerizations affords
material processing with high reaction rates at room temperature, low energy input, and spatial and
temporal control. Owing to the mild reaction conditions, photopolymerization reactions have
become a rapidly explored new approach for creating biomaterials.
