A novel lipoprotein-mimic nanocarrier composed of the modified protein and lipid for tumor cell targeting delivery.

Ursodeoxycholic acid (UA) modified protein-lipid nanocomplex (uP-LNC) as a novel biomimetic nanocarrier was developed for tumor-targeting delivery. Bovine serum albumin (BSA) was used as a model protein and its amino groups were covalently modified by UA. Lipid nanoparticle (LNP) composed of phospholipids, triglycerides and octadecylamine was prepared by using solvent evaporation method and was used as the core. UA modified BSA (uP) was attached onto the surface of LNP by post-insert method and generated the protein-lipid nanocomplex. As the control, cholesteryl hemiglutarate (CH), a non-targeting ligand was also used to modify BSA and then formed CH modified protein-lipid nanocomplex (cP-LNC). The combining efficiency of modified BSA with LNP, determined by Bradford protein assay, increased with the enhancement of substitution degree. The modified BSA and nanocomplex were characterized for the substitute degree, average molecular weight, surface tension, particle size and zeta potential by various physicochemical analyses. In vitro dissolution tests and cell uptake studies were performed by loading coumarin-6 as a fluorescent probe. The results indicated that the UA modified protein attached on the nanoparticles significantly decreased drug release from the nanocomplex in pH 7.4 medium, The uptake of uP-LNC was higher in hepatic carcinoma cells (HepG2 and Bel 7402) than in normal liver cells (L02). Furthermore, the uptake of uP-LNC was significantly higher than that of cP-LNC and LNP in these cells. The uptake was dependent on time, temperature and concentration, and could be inhibited by free UA. In addition, the MTT assay of uP-LNC and u(x)P with various degrees of substitution showed very low cytotoxicity at tested concentrations in all cells. The UA modification served to facilitate the specific receptor and energy mediated endocytosis process of the protein-lipid nanocomplex and enabled this nanocomplex to be a potential nanocarrier for tumor-targeting drug delivery.