Degradation profiles (Mw relative to Mwo as a function of position and time) for various spherical matrices of 10kDa PSA. Matrix size is varied (A. 2 cm, B. 2 mm, C. 200 μm) to explore the various erosion schemes: A) surface erosion, B) a transition from surface to bulk erosion and C) bulk erosion. The lifetime of each matrix changes with its size, such that each line in A) represents 1 month, B) represents 1 day and C) represents 2 hours. In each figure, the line furthest to the right and top indicates the earliest time point.