Considering the comparable swelling of both brushes, the reduction in surface adsorption compared to HD-30 brushes indicates some level of infiltration of BMP2 within thick PSPMA brushes, but a more accessible binding to sparser brushes, presumably able to accommodate some level of infiltration and conformational rearrangement. Presumably, this could also account for the partial desorption observed for both HD-10 and LD-10 PSPMA brushes. Overall, this adsorption behaviour is reminiscent of the adsorption of oligonucleotides of varying sizes, adsorbing to cationic polyelectrolyte brushes in a size and density dependent manner .