Systematic investigation of the thermodynamics of HSA adsorption to N-iso-propylacrylamide/N-tert-butylacrylamide copolymer nanoparticles. Effects of particle size and hydrophobicity.

Nanoparticles in biological fluids almost invariably become coated with proteins that may confer nanomedical and nanotoxicological effects. Understanding these effects requires quantitative measurements using simple systems. Adsorption of HSA to copolymer nanoparticles of varying hydrophobicity and curvature was studied using ITC, yielding stoichiometry, affinity, and enthalpy changes upon binding. The hydrophobicity was controlled via the co-monomer ratio, N-iso-propylacrylamide/N-tert-butylacrylamide. The most hydrophobic particles become fully covered with a single layer of protein, except at high curvature.