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

AbstractColloidal 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 74nm, and carried out our experiment under 0.2% (hypoxic) and 21% (normoxic) oxygen levels using MCF-7 and HeLa cells. Our results showed that NPs of size 50nm 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

Uniaxial hydroxyapatite growth on a self‐assembled protein scaffold

Biomineralization is a crucial process whereby organisms produce mineralized tissues such as teeth for mastication, bones for support, and shells for protection. Mineralized tissues are composed of hierarchically organized hydroxyapatite crystals, with a limited capacity to regenerate when demineralized or damaged past a critical size. Thus, the development of protein‐based materials that act as artificial scaffolds to guide hydroxyapatite growth is an attractive goal both for the design of ordered nanomaterials and for tissue regeneration. In particular, amelogenin, which is the main protein that scaffolds the hierarchical organization of hydroxyapatite crystals in enamel, ame-logenin recombinamers, and amelogenin‐derived peptide scaffolds have all been investigated for in vitro mineral growth. Here, we describe uniaxial hydroxyapatite growth on a nanoengineered amelogenin scaffold in combination with amelotin, a mineral promoting protein present during enamel formation. This bio‐inspired approach for hydroxyapatite growth may inform the molecular mechanism of hydroxyapatite formation in vitro as well as possible mechanisms at play during mineralized tissue formation