Varying the PAA polyanion molecular weight (450, 5, or 1.8 kDa) in BMP-2 / PTK-BAA films (A) does not appreciably change the total BMP-2 loading as visualized by fluorescence imaging of films with Cy5-labeled protein. However, PAA1.8 samples (B) display significantly more sensitivity to oxidation via BMP-2 release at both 1 mM and 0.1 mM H2O2 compared against higher molecular weight PAA formulations (n=3 per treatment; *p<0.05, **p<0.005, ***p<0.0005 for 1 mM H2O2 vs PBS; #p<0.05 for 0.1 mM H2O2 vs PBS). All samples featured 30 tetralayer films constructed on PLGA scaffolds.