Glutathione-depletion mesoporous organosilica nanoparticles as a self-adjuvant and Co-delivery platform for enhanced cancer immunotherapy.

Silica based nanoparticles have emerged as a promising vaccine delivery system for cancer immunotherapy, but their bio-degradability, adjuvanticity and the resultant antitumor activity remain to be largely improved. In this study, we report biodegradable glutathione-depletion dendritic mesoporous organosilica nanoparticles (GDMON) with a tetrasulfide-incorporated framework as a novel co-delivery platform in cancer immunotherapy. Functionalized GDMON are capable of co-delivering an antigen protein (ovalbumin) and a toll-like receptor 9 (TLR9) agonist into antigen presenting cells (APCs) and inducing endosome escape. Moreover, decreasing the intracellular glutathione (GSH) level through the -S-S-/GSH redox chemistry increases the ROS generation level both in vitro and in vivo, facilitating cytotoxic T lymphocyte (CTL) proliferation and reducing tumour growth in an aggressive B16-OVA melanoma tumour model. Our results have shown the potential of GDMON as a novel self-adjuvant and co-delivery nanocarrier for cancer vaccine.