금 나노 소재를 이용한 항암 치료제 개발

Abstract

With the progress of life science and biotechnology, various kinds of bio/pharmaceuticals have been developed: chemical drugs like penicillin and aspirin, and biopharmaceuticals like protein/peptide drugs and nucleotide therapeutics. Recently, nanomedicine has been extensively investigated on the basis of BT, IT, NT fusion technologies. Nanomedicine is the term for the use of advanced nanobiotechnology to the medicine. In this work, Au based nanomedicines were developed for the treatment of cancer. Cancer is defined as an uncontrolled proliferation of cells by genetic disorder. A variety of Au nanostructures were synthesized and applied to cancer therapy with hyaluronic acid (HA), small interfering RNA (siRNA) and doxorubicin (DOX). HA is a biodegradable, biocompatible, non-toxic and natural linear polysaccharide. Due to its excellent physicochemical and biological properties, HA has been widely used for various medical applications. SiRNA is double stranded RNA molecule with 20~ 25 nucleotides. SiRNA interferes with the expression of a specific disease gene and regarded as one of the new paradigm therapeutics with negligible immune responses. DOX has been widely used for cancer therapy in the bladder, prostate, colon, breast, stomach, lung, and so on. Part 1 describes the synthesis and characterization of Au nanomaterials with various nanostructures for cancer therapy. First, size-tunable Au nanoparticles with a dimension from 7.5 nm to 43.8 nm were synthesized using chloroauric acid and trisodium citrate. Second, Au nanocages were prepared by galvanic exchange of Ag nanocubes. The Au nanocages exhibited controlled surface plasmon resonance from 412 nm to 723 nm. Third, Au nano half-shells were successfully prepared by the deposition of Au on the silica surface with a thermal evaporator. Fourth, surface modification of Au nanomaterials was carried out to provide functional groups like carboxyl and amine groups on the Au surface using lipoic acid and cysteamine dihydrochloride. Zeta-potential and dynamic light scattering analyses confirmed the successful introduction of carboxyl and amine groups to Au nanoparticles. Part 2 describes a novel layer-by-layer assembly of cysteamine modified Au nanoparticles (AuCM) / siRNA / polyethyleneimine (PEI) / HA complex for target specific intracellular delivery of siRNA by HA receptor mediated endocytosis. Atomic force microscopic and zeta potential analyses confirmed the formation of AuCM/siRNA/PEI/HA complex having a particle size of ca. 38 nm with slightly negative surface charge characteristics. Microscopic images and dark-field bioimaging clearly visualized the target specific intracellular delivery of AuCM/siRNA/PEI/HA complex to B16F1 cells with HA receptors such as CD44, HARE and LYVE-1. With negligible cytotoxicity, AuCM/siRNA/PEI/HA complex showed an excellent target specific gene silencing efficiency higher than 70% in B16F1 cells in the presence of 50 vol% serum. Taken together, AuCM/siRNA/PEI/HA complex was thought to be developed as target specific siRNA therapeutics for the treatment of various diseases in the tissues with HA receptors. Part 3 describes the cock-tail cancer therapy using HA-DOX conjugate coated with Au. HA-DOX conjugate was successfully synthesized by the amide bond formation between amine groups of DOX and carboxylic groups of HA activated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysulfosuccinimide. 1H NMR analysis confirmed the successful synthesis of HA-DOX conjugate. HA-DOX conjugates self-assembled to micelle-like nanoparticles in aqueous solution and the nanoparticles were coated with Au with a thermal evaporator. TEM analysis confirmed the successful Au coating on HA-DOX conjugate micelles with a 15-nm-thickness. The HA-DOX conjugate coated with Au will be applied to the cock-tail cancer therapy of chemotherapy and hyperthermia.