The induction of maturation on dendritic cells by TiO2 and Fe3O4@TiO2 nanoparticles via NF-κB signaling pathway

• We designed and synthesized nano-TiO2 and Fe3O4@TiO2.
• We examined the physiochemical characters of two kinds of nanoparticles.
• Nano-TiO2 and Fe3O4@TiO2 could enhance the maturation of dendritic cells.
• Both kinds of nanoparticles could help the cellular uptake of Ovalbumin.
• NF-κB pathway and cytokine secretion were activated by nano-TiO2 and Fe3O4–TiO2.

Nanomaterials are increasingly used in many fields, including drug vectors and vaccine formulation. In this study, nano-TiO2 and magnetic Fe3O4@TiO2 were synthesized and their abilities to activate dendritic cells were investigated. The signaling pathway involved in their effects on the cellular functions was also explored. First, nano-TiO2 and Fe3O4@TiO2 were prepared with diameters of 82 nm and 63 nm, and zeta potentials of 41.5 mV and 30.2 mV, respectively. The magnetic property of Fe3O4@TiO2 was detected to be 12.9 emu/g. Both kinds of nanoparticles were proved to have good biocompatibility in vitro. Second, the exposure of nano-TiO2 and Fe3O4@TiO2 caused an increased expression of TNF-α, CD86 and CD80, and besides, Fe3O4@TiO2 showed a certain up-regulation on MHC-II. The cellular uptake of Ovalbumin on BMDCs could be strongly improved by nano-TiO2 and Fe3O4@TiO2 as detected via flow cytometer and confocal observation. Further investigation revealed that nano-TiO2 and Fe3O4@TiO2 significantly increased the NF-κB expression in the nucleus, indicating that the NF-κB signaling pathway was involved in the dendritic cell maturation. Our results suggested that nano-TiO2 and Fe3O4@TiO2 may function as a useful vector to promote vaccine delivery in immune cells, and Fe3O4@TiO2 provided a possibility to deliver and track vaccines via its magnetofection.

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