Drug delivery and cell interaction of adhesive poly(ethyleneimine)/sulfated polysaccharide complex particle films

Herein, the authors report and review polyelectrolyte complex (PEC) nanoparticles (NPs) loaded with zoledronate (ZOL) and simvastatin and their effects on bone cells. PEC NPs are intended for modification of bone substitute materials. For characterization, they can be solution casted on germanium (Ge) substrates serving as analytically accessible model substrate. PEC NPs were generated by mixing poly(ethyleneimine) (PEI) either with linear cellulose sulfate (CS) or with branched dextransulfate (DS). Four important requirements for drug loaded PEC NPs and their films are addressed herein, which are the colloidal stability of PEC dispersions (1), interfacial stability (2), cytocompatibility (3), and retarded drug release (4). Dynamic light scattering measurements (DLS) showed that both PEI/CS and PEI/DS PEC NP were obtained with hydrodynamic radii in the range of 35-170 nm and were colloidally stable up to several months. Transmission FTIR spectroscopy evidenced that films of both systems were stable in contact to the release medium up to several days. ZOL-loaded PEI/CS nanoparticles, which were immobilized on an osteoblast-derived extracellular matrix, reduced significantly the resorption and the metabolic activity of human monocyte-derived osteoclasts. FTIR spectroscopy at cast PEC/drug films at Ge substrates revealed retarded drug releases in comparison to the pure drug films.