HA-coated chitosan nanoparticles for CD44-mediated nucleic acid delivery.

CD44, the main receptor of hyaluronic acid (HA), is overexpressed in several pathological conditions and therefore can be seen as an interesting target for therapeutic intervention. Here, an approach using HA-coated chitosan (CS)-triphosphate (TPP) nanoparticles is investigated, using CS with different molecular weight (25 and 684 kDa), which influences HA presentation, and enzymatic and pH stability. In a study of nuclease stability, post-digestion of nanoparticles with chitosanase reveals that pDNA is at least partially degraded by DNAse; this may suggest that literature results overestimate the polyplex stability against nucleases. Using cells with a significantly different CD44 expression (RAW 264.7 macrophages-high levels; K562 leukemia cells-low levels; Kelly neuroblastoma cells-absent), the selectivity of CD44-mediated transfection is proven. Further, using luciferase pDNA and then later anti-luc siRNA, low MW CS-based nanoparticles show the best results despite a lower internalization efficiency; this effect is ascribed to a more efficient endosomal disruption and nucleic acid de-complexation.