Antifouling performance of nano-sized spherical poly(N-hydroxyethyl acrylamide) brush.

The biomedical applications of nanoparticles are still impeded by the non-specific adsorption of proteins, cells, or others biological species in vivo/in vitro. In this work, poly(N-hydroxyethyl acrylamide) was hired to modify a solid polymer core, polystyrene (PS) nanoparticles, via surface-initiated photo-emulsion polymerization to form nano-sized spherical poly(N-hydroxyethyl acrylamide) brush (PS@PHEAA). Its antifouling ability and stability were investigated by dynamic light scattering (DLS), turbidimetric titration, and isothermal titration calorimetry (ITC). The size of PS@PHEAA was constant as a function of pH, while slightly changed with ionic strength in single protein solution. ITC data confirmed that protein was slightly adsorbed on PS@PHEAA and the ionic strength influenced the adsorption. All characterizations demonstrated that PHEAA layer reduced the interaction between nanoparticles and proteins. Thus, these nanoparticles ideal candidates for future applications in the biomedical field.