Oral administration of chondroitin sulfate-functionalized nanoparticles for colonic macrophage-targeted drug delivery

Orally targeted delivery of anti-inflammatory drugs to macrophages has attracted great attention for minimizing the symptoms of ulcerative colitis (UC). In this investigation, we encapsulated curcumin (CUR) into polymeric nanoparticles (NPs), and conjugated chondroitin sulfate (CS) to their surfaces. The resulting CS-NPs had an average diameter of 281 nm, monodisperse size distribution and negatively charged surface. Cell experiments indicated that these NPs showed excellent biocompatibility, and yielded significantly higher cell internalization efficiency in Raw 264.7 macrophages than their counterparts (carboxymethyl cellulose-functionalized CUR-encapsulated NPs, CUL-NPs). Moreover, CS-NPs exhibited a dramatically stronger capacity to inhibit the secretion of the major pro-inflammatory cytokines from lipopolysaccharide-stimulated macrophages compared with CUL-NPs. In vivo experiments revealed that oral administration of chitosan/alginate hydrogel embedding CS-NPs achieved better therapeutic outcomes against UC comparied with CUL-NPs. Collectively, our results demonstrated that CS-NP-embedded hydrogel held a great promise to be developed as a macrophage-targeted drug delivery system for UC treatment.