(A) Release of GFP from GST-GFP PEGD-GSH microspheres in the presence of () 0, 11 (), 22 (), 44 (), or 110 () nM thrombin as detected by fluorescent GFP signal. Each point represents the mean plus or minus the standard deviation of three independent samples. (B) Representative brightfield and epifluorescent micrographs depicting GST-GFP (green) associated with microspheres before (top row) or after (bottom row) release in response to thrombin (1.8 µM). (C) Rate (v) of GFP liberation from GST-GFP (unbound; ) and GST-GFP (bound; ) bound to PEGDA-GSH microspheres for the linear portion of the rate curve, typically the first 1 hour. Each point represents the mean plus or minus the standard deviation of three independent samples.