A polyethylenimine functionalized porous/hollow nanoworm as a drug delivery system and a bioimaging agent

Abstract

A wormstructured and nanosized porous/hollow polyethyleneimine (PEI) functionalized Gd₂O₃/Fe₃O₄ composite was fabricated as a drug carrier and a bioimaging agent. The effect of PEI's chain length on the size and morphology of the nanoworm was investigated and the results indicated that the nanoworm modified with PEI (10 000 molecular weight) (designated as p-nanoworm) possessed a suitable size and a porous/hollow structure. Meanwhile, the p-nanoworm could effectively prevent the leakage of Gd ions under different pH conditions because of plenty of amino groups on their surface. Compared with contrast agents of clinical use, the p-nanoworm displayed MR enhancement with a high r₁ relaxivity of 5.58 s⁻¹ mM⁻¹ per gadolinium atom. Cisplatin (CDDP), a clinical anticancer drug, could be easily loaded into the pores and lumen of the p-nanoworm (p-nanoworm-CDDP) and also controllably released by adjusting the pH value. Cell assay suggested that the p-nanoworm possessed satisfactory biocompatibility and meanwhile could promote CDDP uptake of HeLa cells and enhance the inhibition effect on HeLa cells. In addition, p-nanoworm-CDDP showed a negligible cytotoxicity on normal human cells, indicating that the side effect of CDDP is reduced. Thus, the p-nanoworm could have a potential application for the diagnosis and therapy of cancer.