Chitosan-ceramide coating on gold nanorod to improve its physiological stability and reduce the lipid surface-related toxicity

Abstract

Gold nanoparticles are promising materials for many applications that include imaging, drug delivery, and photothermal therapy. However, AuNPs can be unstable and/or toxic. We purposed to improve the stability and reduce toxicity of gold nanorods (AuNR) upon coating with biocompatible polymer, chitosan-ceramide (CS-CE), without replacing the original layer, CTAB. CS-CE-coated AuNR was prepared by simple mixing for 24 h and purified by centrifugation. The coating was confirmed by UV-Vis absorption analysis and surface charge and size measurement. We prepared nanorods with CS or CS-CE coating at two different concentrations (5 and 10% AuNR), the resulting in larger nanorods with a more positive surface-charge than that of AuNR. We investigated the UV-absorption and protein adsorption of the polymer coated nanorods. Based on the protein adsorption, AuNR-CS-CE was found to be more stable under physiological conditions than AuNR-CS. The cell internalization assay revealed that Hela cells internalized higher amounts of AuNR-CS-CE than that of AuNR-CS. Cytotoxicity study revealed that AuNR- CS-CE has lower toxicity than AuNR against HeLa cells. The CS-CE coating improved the stability of AuNR under physiological conditions via the hydrophobic interactions between the AuNR lipid surface and the ceramide anchor in the CS backbone as well as.