Self-assembled CpG oligodeoxynucleotides conjugated hollow gold nanospheres to enhance cancer-associated immunostimulation.

To realize efficiently cellular uptake and enhance the immunostimulation, thiolated cytosine-phosphate-guanine (CpG) oligodeoxynucleotides (ODNs) were self-assembled on hollow gold nanospheres (HGNs) to form CpG-HGNs. The cellular uptake of CpG-HGNs in immune cells was studied in RAW 264.7 cells. Due to the enhanced delivery efficiency, CpG-HGNs exhibited a higher immune stimulatory activity compared with CpG ODNs, resulting in a dramatically enhanced secretion of proinflammatory cytokines. In addition, CpG-HGNs showed low cytotoxicity in RAW 264.7 cells. CpG-HGNs could potentially realize synergistic photothermal therapy and immunotherapy in vivo.