The endemic nature of cancer is such that annual projections on incidences remains high in spite of advances made with available therapy and efficient control measures such as  prevention, early detection, and management. Nano medicine has significantly impacted on current treatment strategies, especially in cancer therapy.  The need to design novel drugs or therapeutic genes with higher efficiency and safety has stimulated the development of innovative delivery strategies. This study covers the formulation of gold based nanoparticles, their functionalization with chitosan, and their ability to deliver anticancer drugs and reporter genes, respectively. All nanoparticles and their nanocomplexes were chemically, structurally and morphologically characterised using UV-vis spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). Our studies have shown that these NPs were generally of nanosize, colloidally stable, non-toxic and were readily taken up by the cells. Nanoparticles showed significant binding of pDNA, with drug binding being greater than 50%. In vitro cytotoxicity profiles were determined using the MTT assay, with significant cell death recorded in the human breast adenocarcinoma (MCF-7), hepatocellular carcinoma (HepG2) and colorectal adenocarcinoma (Caco-2) cell lines for doxorubicin loaded platiunum-gold nanoparticles. Low cytotoxicity coupled with significant luciferase gene expression was noted in vitro using gold nanoparticles. Overall, the drug-nanocomplexes exhibited high cancer cell specificity and pH-triggered drug release, with gene-nanocomplexes producing targeted transfection in HeLa cells. These nanoparticles have opened a new avenue for the delivery of anticancer drugs and therapeutic genes. Further optimizations may be needed prior to in vivo applications.

Keywords: Gold; Platinum; Nanoparticles; Drug/gene delivery; Cytotoxicity.