RNA was collected from constructs after 1 d and 7 d, purified, and expression determined using real time RT-PCR. Expression of matrix type-1 MMP (MT1-MMP, A), MMP2 (B) and MMP9 (C) was measured. Expression levels were normalized to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in each sample and then to expression in 27 mg/mL PEGVS at 1 d (ΔΔCt method). *: p < 0.05, relative to 27 mg/mL (same day); &: p < 0.05 relative to day 1 (same composition). N=3.