Abstract
Nanocarriers have attracted enormous interest due to their broad biomedical applications.
Because of their unique physical and chemical properties, nanomaterials are reactive or
catalytic, and thus can be potentially toxic. An important mechanism of nanotoxicity is the
over production of reactive oxygen species (ROS), which leads to DNA damage, unregulated
proinflammatory signal, change in cell motility, cytotoxicity and cancer initiation. In this
study, amine coated gold nanoparticle with controlled size (10nm, 25nm, 50nm, 80nm, and
125nm) was used as a model system to systemically examine their in vitro cellular response
on phagocytic J774A.1 and keratinocytes HeCaT, with a focus on overproduction of ROS.
ROS production was investigated by both fluorescence based intracellular method
(H2DCFDA) and highly sensitive FLIM (fluorescence lifetime imaging microscopy)
technique. The cellular uptaken, cytotoxicity and genotoxicity were further investigated. We
found the surface charge was increased with the increase of the particle size. The particle with
different size can be uptaken efficiently by both cell types and distributed mainly in the
perinuclear mitochondrial clustering after 4 hours. There was a strong cytotoxicity from
80nm group in HeCaT but not in J774A.1. With the increase of the particle size but same total
gold amount, there was an increase ROS production detected by H2DCFDA and confirmed
by FLIM. Therefore, gold nanoparticle may have a cell type specific toxicity. Their physical
and chemical property has a strong influence on mitochondrial activity and ROS production.
