Hyaluronic acid/poly-<scp>l</scp>-lysine bilayered silica nanoparticles enhance the osteogenic differentiation of human mesenchymal stem cells

Herein, we evaluate the influence of a PLL-HA bilayer on the surface of silica nanoparticles on their capacity to induce the osteogenic differentiation of human bone marrow stem cells (hBMSCs), as a function of their concentration (50 μg mL^-1, 25 μg mL^-1 and 12.5 μg mL^-1). To this purpose, we synthesized silica nanoparticles (diameter of ∼250 nm; ζ-potential of -25 mV) that were coated with PLL-HA (diameter of ∼560 nm; ζ-potential of -35 mV). The cell viability, cell proliferation, protein quantification (i.e. MTS, DNA and ALP, respectively) and gene expression (of osteogenesis-related genes: ALP, osteocalcin, collagen type I, bone sialoprotein, Runx-2, osteopontin and osterix) were monitored, for 21 days. We observed the overexpression of most of the tested osteogenic transcripts in the hBMSCs cultured with SiO₂-PLL-HA, at concentrations of 25 μg mL^-1 and 12.5 μg mL^-1. These results indicate that the proposed nanoparticles temporarily improve the osteogenic differentiation of hBMSCs at low nanoparticle concentrations.