A facile method to prepare heparin-functionalized nanoparticles for controlled release of growth factors

A new, facile method to prepare the heparin-functionalized PLGA nanoparticle (HEP-PLGA NP) for the controlled release of growth factors is developed. This system is composed of PLGA as a hydrophobic core, Pluronic F-127 as a hydrophilic surface layer, and heparin as the functional moiety. HEP-PLGA NPs were prepared by a solvent-diffusion method without chemical modification of the components. The entrapment of heparin molecules was confirmed by a negatively increased zeta potential value and the specific binding affinity to antithrombin III. The average diameter and the surface charge of the nanoparticles were ranged from 139±2 to 188±4 nm and from –26.0±1.1 to –44.1±1.3 mV by increasing the amount of heparin during the nanoparticle preparation. Accordingly, the amount of heparin on the nanoparticle increased from 0% to 4.7%. As a model in vitro release experiment, lysozyme was loaded into HEP-PLGA NPs, and a sustained release profile over 2 weeks was obtained with maintaining its bioactivity. The release of rhVEGF, one of the heparin-binding growth factors, showed a more sustained and prolonged profile than that of lysozyme over one month.