Fig. 4

Nanoparticle optimization strategies used to reverse immunosuppression in the tumor microenvironment. a Some nanoparticles are used to target M2 TAMs. b Indoleamine 2,3-dioxygenase-1 (IDO1) siRNA-loaded lipid nanoparticles enhance immunogenic cell death (ICD) to promote immunogenic death of tumor cells. Reprinted by permission from [73]. c Co-encapsulation of the ICD inducer oxaliplatin and the IDO inhibitor indomethacin in mesoporous silica nanoparticles (MSNPs) coated with lipid bilayers. Reprinted by permission from [74]. DCs dendritic cells, CTLs cytotoxic T lymphocytes, OXA oxaliplatin, CRT calreticulin, HMGB-1 high-mobility group box 1, IND indoximod