  A novel multifunctional nanodevice based in doxorubicin (DOX)- loaded
mesoporous silica nanoparticles (MSNs) as nanoplatforms for the assembly of
different building blocks has been developed for bone cancer treatment. These
building blocks consists of: i) a polyacrylic acid (PAA) capping layer grafted
to MSNs via an acid-cleavable acetal linker, to minimize premature cargo
release and provide the nanosystem of pHresponsive drug delivery ability; and
ii) a targeting ligand, the plant lectin concanavalin A (ConA), able to
selectively recognize, bind and internalize owing to certain cell-surface
glycans, such as sialic acids (SA), overexpressed in given tumor cells. This
multifunctional nanosystem exhibits a noticeable higher internalization degree
into human osteosarcoma cells (HOS), overexpressing SA, compared to healthy
preosteoblast cells (MC3T3-E1). Moreover, the results indicate that small DOX
loading leads to almost 100% of osteosarcoma cell death in comparison with
healthy bone cells, which significantly preserve their viability. Besides, this
nanodevice has a cytotoxicity on tumor cells 8- fold higher than that caused by
the free drug. These findings demonstrate that the synergistic combination of
different building blocks into a unique nanoplatform increases antitumor
effectiveness and decreases toxicity towards normal cells. This line of attack
opens up new insights in targeted bone cancer therapy.
