Role of nanotechnology in modulating the tumor microenvironment to enhance immunotherapy efficacy

Table 2 Summary of nanoparticle designs showing size, surface charge, functional modifications, and their application in targeting key immunosuppressive immune cells such as tumor-associated macrophages, myeloid-derived suppressor cells, regulatory T cells, and dendritic cells within the tumor microenvironment

Nanoparticle type	Size (nm)	Surface charge	Surface modification	Payload	Target immune cell (s)	Key effect	Ref.
Polymeric nanocluster (SPN-R848)	Approximately 100	Slightly positive	pH-responsive polymer shell	TLR7/8 agonist (R848)	TAMs, DCs	Polarizes M2 TAMs to M1, activates DCs	[49]
Lipid-coated CaCO3 NPs (CaGlu)	Approximately 150	Neutral	β-glucan surface	Calcium carbonate + β-glucan	TAMs, Tregs	Repolarizes TAMs, suppresses Tregs	[50]
Biomimetic dendritic cell-like NP	Approximately 120	Near neutral	Decorated with anti CD3/CD28/PD-1	Immunomodulatory antibodies	DCs, T cells	Activates DCs, enhances T cell priming	[56]
Iron oxide NP	Approximately 50	Positive	Mannose ligand	Iron core	TAMs	Promotes M1 polarization via ROS generation	[47]
Liposome-based RNAi NP	Approximately 90	Slightly negative	PEGylation, targeting peptide	siRNA targeting IDO/TGF-β	MDSCs, Tregs	Suppresses immunosuppressive pathways	[51]

TAM: Tumor-associated macrophages; Tregs: Regulatory T cells; MDSCs: Myeloid-derived suppressor cells; TGF-β: Transforming growth factor-beta; IDO: Indoleamine-2,3-dioxygenase; NP: Nanoparticle.