Determining the Size Dependence of Colloidal Gold Nanoparticle Uptake in a Tumor-like Interface (Hypoxic)

Colloidal gold nanoparticles (GNPs) are being used as drug delivery vehicles and radiation dose enhancers in cancer therapy. Oxygen concentration in human tumours is highly heterogeneous with many regions at very low levels of oxygen (hypoxia). A majority of tumours contain regions with oxygen pressure values of less than 0.7% in the gas phase. The purpose of this study was to investigate how the size of the NPs affects their uptake process in a tumour-like hypoxic environment. We used GNPs of diameter 15, 50, and 74 nm, and carried out our experiment under 0.2% (hypoxic) and 21% (normoxic) oxygen levels usingMCF-7 and HeLa cells. Our results showed that NPs of size 50 nm had the highest uptake following prolonged exposure to hypoxia. There was no significant toxicity introduced by NPs under hypoxic conditions. These findings will play a vital role in the optimization of GNP-based therapeutics in cancer treatment. (C) 2014 The Authors. Published by Elsevier B.V.