Folate-modified CORM-2-loaded lipid nanoparticles for targeted carbon monoxide delivery

Abstract

The aim of this study was to investigate folate receptor-targeted lipid nanoparticles containing CORM-2 (Fol-CORM-2-NPs) for targeted delivery of carbon monoxide to macrophages. Fol-CORM-2-NPs were prepared by nanotemplate engineering technique with palmityl alcohol as a solid lipid and Tween40/Span40/Myrj S40 as a surfactants mixture. The physical properties of Fol-CORM-2-NPs were evaluated by dynamic light scattering and transmission electron microscopy. The incorporation efficiency of CORM-2 into Fol-CORM-2-NPs was determined by quantifying ruthenium using ICP-AES. CO release from Fol-CORM-2-NPs were assessed by myoglobin assay. In vitro cytotoxicity of Fol-CORM-2-NPs was evaluated with the MTT assays. In vitro anti-inflammatory effects were evaluated by nitric oxide assay in lipopolysaccharide-stimulated RAW 264.7 macrophages. The targeting ability of Fol-CORM-2-NPs was evaluated by competitive inhibition assay after pretreatment with free folate. The cellular uptake study revealed that Fol-CORM-2-NPs were internalized through folate. Spherical Fol-CORM-2-NPs were around 100 nm with narrow particle size distribution. About 90% of CORM-2 was incorporated into Fol-CORM-2-NPs. The sustained CO release from Fol-CORM-2-NPs was observed and the half-life of CO release increased up to 40 times compared with that of CORM-2 solution. Non-cytotoxicity of Fol-CORM-2-NPs was confirmed by evaluating in vitro cell viability of RAW 264.7 macrophages by MTT assay. Through targeting to Raw 264.7 cells, Fol-CORM-2-NPs exhibited better effects than CORM-2-NPs in NO inhibition, suggesting greater anti-inflammatory activity. Taken together, Fol-CORM-2-NPs have a great potential for targeted CO therapeutics against inflammation via folate receptor-mediated specific delivery.