  Nanographene oxide (nGO)-mediated hyperthermia has been increasingly
investigated as a localised, minimally invasive anticancer therapeutic
approach. Near InfraRed (NIR) light irradiation for inducing hyperthermia is
particularly attractive, because biological systems mostly lack chromophores
that absorb in this spectral window, facilitating the selective heating and
destruction of cells which have internalized the NIR absorbing-nanomaterials.
However, little is known about biological effects accompanying nGO-mediated
hyperthermiaat cellular and molecular levels.In this work, well-characterised
pegylatednGOsheets with an hydrodynamic size of 300 nm were incubated with
human Saos-2 osteosarcoma cells for 24h and their incorporation verified by
flow cytometry and confocal microscopy. No effect on cell viability was
observed after nGO incorporation by Saos-2 cells. However, a proliferation
delay was observed due to the presence of nGO sheets in the cytoplasm.1H NMR
metabolomicswas employed to screen for changes in the metabolic profile of
cells, as this could help to improve understanding of celular responses to
nanomaterials and provide new endpoint markers of effect.Cells incorporating
nGO sheets showed noticeable changes in 10 metabolites compared to control
cells, including decreased levels of several amino acids, taurine and creatine
and increased levels of phosphocholine and uridine/adenosine nucleotides. After
NIR irradiation, cells showed decreases in glutamate and uridine nulceotides,
together with increases in glycerophosphocholine and adenosine monophosphate.
Overall, this study has shown that the celular metabolome sensitively responded
to nGO exposure and nGO-mediated hyperthermia and that NMR metabolomics is a
powerful tool toinvestigate treatment responses.
