Background: When localized in cells, gold nanoparticles (GNPs) enhance absorption
of ionizing radiation and hence biological damage. They have the potential to increase
the efficiency of radiotherapy cancer treatment.
Objective: To investigate the dose enhancement and biomolecular radiosensitization induced
by ultra-stable polyvinyl alcohol coated gold nanoparticle (PVA-GNPs).
Methods: The dose enhancement induced by PVA-GNPs was quantified by Fricke chemical
dosimetry. The absorbed dose as a function of PVA-GNP concentration for irradiation
with 80 and 100 kVp X-rays and 60Co γ-rays. The efficiency of PVA-GNPs to sensitize
plasmid DNA to 80 kVp X-rays was measured by gel electrophoresis for a water solution
of PVA-GNPs and DNA in a 1:1 ratio. Subcellular localization and the radiosensitization
of PVA-GNPs in F98 glioma cells was performed.
Results: Under X-ray irradiation, the absorbed dose increased with PVA-GNP concentration.
Average dose enhancements were 1.89 ± 0.14 and 2.25 ± 0.11 for 80 and 100 kVp
X-rays, respectively, which led to an increase in DNA strand breaks and interduplex
crosslinks. Conversely, no significant dose enhancement was found with 60Co γ-rays (P =
0.77). PVA-GNPs accumulated near the nuclear membrane and in vesicle-like structures
in the cytoplasm, but did not localize in the nucleus. The induction of radioenhancement
by 2-fold was observed when combined 500 nM PVA-GNPs with 4 Gy X-rays.
Conclusion: Radiosensitization by PVA-GNPs was observed under 80 and 100 kVp Xray
irradiation. These results support the potential application of these highly stable nanoparticles
to enhance the benefits of low-energy X-ray radiotherapy in cancer treatments.