Table 1 Optimizing approaches for NPs-based tumor immunotherapy
From: Advances in technology and applications of nanoimmunotherapy for cancer
NPs performance for optimizing | Common tuning factors | Mechanism | Examples of optimizing strategy | References |
|---|---|---|---|---|
NPs penetrability | Size of NPs | Switch PRs to small particles once accumulating at the tumor site for deep penetration | Size shrinkage triggered by acid PH, overexpressed enzyme, redox condition,or reactive oxygen species (ROS) | |
Dense tumor matrix | Functionalizing NPs with enzymes that degrade tumor ECM components | Conjugate bromelain to mesoporous silica nanocarrier; Coupling hyaluronidase to the surface of PLGA-NPs | ||
NPs selectivity | Tumor selectivity | Switch PRs to larger particles once accumulating at the tumor site for longer retention | Initial nanoparticles with relatively small sizes form aggregations which induced by internal stimuli (such as enzymes, PH and redox), or triggered by external stimuli (such as light, temperature) | [105] |
Coating with NPs with biologically derived cell membranes | Erythrocyte membrane-enveloped PLGA-NPs;Cancer cell membrane coated PLGA-NPs | |||
Coupling tumor homing peptide on the surface of NPs | Coupling iRGD on the surface of NPs | [111] | ||
Cellular selectivity | Attaching a ligand or antibody fragments that are specific for the targeting cell | CD40-coupled PLGA-NPs targeting DC cells; G5-methotrexate nanoparticles targeting the folate receptor-2 (FOLR2) on tumor associated macrophage | ||
Intracellular selectivity | Tuning the surface chemistry of NPs to facilitate the escape of endolysosomal pathway | Cationic particle surfaces facilitate NPs to release into the cytosol, rely on the “proton sponge effect” at low PH | [114] | |
Incorporate cell-penetrating peptides on the NPs to enhance the intracellular delivery | Incorporate cell-penetrating peptides KALA on the NPs surface | [115] | ||
NPs versatility | Sensitive NPs to external stimuli | Take advantage of features of sensitive NPs to develop combination therapy | Radio-sensitive NPs for radiotherapy; photo-sensitive NPs for phototherapy; magnetic-sensitive NPs for magnetodynamic therapy | |
Theranostic NPs | Combine the function of imaging and therapy for some NPs | Theranostic nanoreactor for imaging-guided combined tumor therapy;Theranostic applications of nanodiagnosis and nanotherapy with some NPs, including polymeric NPs, quantum dots, magnetic NPs | ||
Synergistic immunotherapy | Develop the multi-functional NPs or combine the present therapy methods with NPs based immunotherapy | Combine other classical immunotherapy and molecular targeting treatment, such as PD-1/PD-L1 antibody treatment |