Effects of Nanoparticle Properties on Kartogenin Delivery and Interactions with Mesenchymal Stem Cells

Clinical trials with mesenchymal stem cells (MSCs) have demonstrated potential to treat osteoarthritis, a debilitating disease that affects millions. However, these therapies are often less effective due to heterogeneous MSC differentiation. Kartogenin (KGN), a synthetic small molecule that induces chondrogenesis, has recently been explored to decrease this heterogeneity. KGN has been encapsulated in nanoparticles due to its hydrophobicity. To explore the effect of nanoparticle properties on KGN and MSC interactions, here we fabricated three nanoparticle formulations that vary in hydrophobicity, size, and surface charge using nanoprecipitation: KGN-loaded poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles (hydrophobic surface, negative charge, ~ 167 nm), PLGA–poly(ethylene glycol) (PEG) nanoparticles (hydrophilic surface, positive charge, ~ 297 nm), and PLGA–PEG–hyaluronic acid (HA) nanoparticles (hydrophilic surface, negative charge, ~ 507 nm). We observed differences in KGN loading, release, and suspension stability, with the PLGA particles exhibiting ~ 50% drug loading and PLGA–PEG–HA particles releasing the most KGN. All nanoparticles were found to interact with MSCs with evidence of increased uptake in PLGA–PEG and PLGA–PEG–HA compared with surface association of PLGA particles. Over short times (~ 7 days), MSCs incubated with all KGN-loaded formulations exhibited a similar increase in sulfated glycosaminoglycans, characteristic of chondrogenic differentiation, compared with non-KGN loaded formulations.