Immune-stealth carboxymethyl chitosan-based nanomaterials for magnetic resonance imaging-guided photothermal therapy

Numerous protein-based multifunctional nanomaterials have been studied for biomedical applications. However, the inherent immunogenicity and activation of the complement system of protein-based nanomaterials may cause immunological responses, further leading to hypersensitivity and/or allergic reactions in patients. Herein, carboxymethyl chitosan (CMC) and KMnO4 are used to develop polysaccharide-based MnO2 (CM) nanoparticles as facile, effective and low-immunogenicity nanomaterials for magnetic resonance imaging (MRI)-guided photothermal therapy (PTT). As a proof of concept, indocyanine green (ICG) is loaded in the CM nanoplatform to form a CMC-MnO2-ICG compound (CMI) for MRI-guided photothermal therapy. In vitro studies show that the proposed CMC-based nanomaterials exhibit excellent hemocompatibility and no significant complement activation. The in vivo biosafety experiments also show that the CMC-based nanomaterials have low immunogenicity and will not cause tissue damage. Moreover, the prepared CMI nanoparticles (NPs) possess outstanding photothermal properties and high longitudinal relaxivity (8.47 mM-1 s-1), which achieve successful MRI-guided PTT in tumor-bearing mice. This work draws increasing attention to the hemocompatibility and immunogenicity of high-performance nanoprobes for biomedical applications.