Total collagen contents in porcine carotid arteries, PGS or PLGA constructs, and PGS or PLGA scaffolds were measured per unit wet weight by quantifying 4-hydroxyproline content. (A) Comparison of experimental groups and controls (n = 4, 4, 4, 8, and 8 from left to right). *Porcine carotid arteries contained significantly more collagen than all other groups. (B) Comparison of experimental groups and negative controls only. *PLGA constructs contained significantly more collagen than PGS constructs and uncultured scaffolds. **PGS constructs contained significantly more collagen than uncultured scaffolds. #The tunica adventitia of porcine carotid arteries was removed prior to testing.