Stimuli-responsive nanoparticles by thermal treatment of bovine serum albumin inside its complexes with chondroitin sulfate

Abstract

We combine electrostatic polysaccharide/protein complexation with subsequent thermal denaturation of proteins to produce chondroitin sulfate/bovine serum albumin nanoparticles that do not lose their integrity at neutral and basic pH. Light scattering at a wide angular range shows that nanoparticle size (radius of gyration and hydrodynamic radius) and molar mass may be tuned by the CS/BSA mass ratio while the irreversible protein-protein contacts upon temperature treatment endow the complexes with properties of nanogels. These nanoparticles respond to changes of pH by reversing their surface charge at pH 5.3 while their size responds to the solution ionic strength and pH. The conformational changes of bovine serum albumin upon thermal treatment are confirmed by spectroscopy methods. The ability of the nanoparticles to encapsulate bioactive substances is demonstrated by loading the nutraceutical β-carotene. The methodology of this work may be applied to other polysaccharide/protein systems to produce multi-functional stimuli-responsive nanoparticles for nanodelivery in food science and biomedical applications.