CpG
oligodeoxynucleotides (CpG ODNs) possess strong immunostimulatory activity, which hold great promise in
cancer immunotherapy. However, their therapeutic efficacy is largely limited due to nuclease degradation and poor cellular internalization. Efficiently delivering CpG ODNs into target cells is crucial to improve their therapeutic efficacy.
Boron nitride nanospheres (BNNS) possess advantage as carriers for CpG ODNs. However, their poor aqueous dispersity and low
CpG ODN loading capacity became a big obstacle for further applications. Herein, we develop amino group grafted, mesoporous
silica (MS)-functionalized BNNS as novel nanovectors for
CpG ODN delivery. Modification of BNNS with MS significantly improved the dispersity of BNNS and
CpG ODN loading. BNNS@MS-NH2 exhibited no cytotoxicity and enhanced the delivery of CpG ODNs into macrophages. BNNS@MS-NH2/
CpG ODN complexes triggered enhanced immunostimulation and induced higher amounts of
cytokines. Most importantly, BNNS@MS-NH2/
CpG ODN complexes induced bifurcated
cytokines, which simultaneously simulated the secretion of
IL-6, TNF-α and IFN-α. In contrast,
CpG ODN and BNNS/
CpG ODN complexes could not. The result of the Transwell plate assay suggested that BNNS@MS-NH2/
CpG ODN complexes were more effective in inhibiting
cancer cell growth. Taken together, our findings provide a promising strategy for enhancing
CpG ODN-mediated
cancer immunotherapy.