**5.4 Using nanoparticles to promote phagocytosis**

Another way to potentially enhance the phagocytic response is through the use of nanoparticles. Nanoparticles have been extensively studied for their ability to induce macrophage polarization states, as different types of nanoparticles can influence macrophage polarization toward either a pro-inflammatory (M1) or anti-inflammatory (M2) phenotype. When tumor-associated macrophages (TAMs) recognize nanoparticles as foreign, they will engulf them via phagocytosis, releasing the contents of the

*Harnessing Phagocytosis for Cancer Treatment DOI: http://dx.doi.org/10.5772/intechopen.110619*

nanoparticle within the TAMs. Therefore, nanoparticles can be loaded with drugs or contents designed to induce macrophage polarization toward a more phagocytic phenotype, reprogramming them with an affinity for phagocytosis. This makes nanoparticles a potentially attractive vehicle for delivering therapeutic agents that can boost the immune response against cancer [88, 89].

Additionally, recent studies have shown that nanoparticles can be designed to not only enhance the phagocytic response, but also to help stimulate an anti-tumor T cell response by recruiting T cells and cross-presenting antigens from phagocytosed cells. This highlights the potential for nanoparticles to be used in combination with other immunotherapies, such as CAR-T cells or checkpoint inhibitors, to further enhance the immune response against cancer [55, 88, 89].
