Remote control of protein deposition on magnetoactive composites.

Upon biomaterial implantation into the body, its surface is coated by proteins in a process known as competitive adsorption. It is known that the physicochemical properties of the surface strongly impact the binding kinetics and structural properties of the adsorbed protein layer, and consequently the biological activity of the material. For instance, hydrophobicity causes significant protein conformational changes that provoke mechano-insensitivity of mesenchymal stem cells (MSCs), while polyethylene glycol (PEG) functionalization repels protein adsorption, thereby resulting in "non-fouling" surfaces to which cells cannot adhere. In the current work, we present a magnetoactive composite material composed of a piezoelectric polyvinylidene fluoride matrix with embedded CoFe2O4 nanoparticles (PVDF-CFO) that enables the modulation of fibronectin and collagen type I adsorption using externally applied magnetic fields. Specifically, we demonstrate that exposure to alternating magnetic fields significantly impacts the supramolecular organization of the fibronectin layer and the compaction of collagen fibrils deposited on the composite films.