|
In order to evaluate cytotoxic effects of secondary Auger electron emission(Photon Activation Therapy:PAT)
from alginate-coated iron nanoparticles(Alg-SNP), Alg-SNP-uptaken C6 glioma cell lines were irradiated with 6.89/7.2
Kev synchrotron X-ray. 0-125 Gy were irradiated on three experimental groups including No-SNP group incubating
without SNP as control group, 6hr-SNP group incubating with SNP for 6hr and ON-SNP group incubating with SNP
overnight. Irradiated cells were stained with Acridine Orange(AO) and Edithium Bromide(EB) to count their viability
with fluorescent microscopy in comparison with control groups. AO stained in damaged DNA, giving FL color change in
X-ray plus SNP group. EB did not or less enter inside the cell nucleus of control group. In contrast, EB entered inside the
cell nucleus of Alg-SNP group which means more damage compared with Control groups. The results of MTT assay
demonstrated a X-ray dose-dependent reduction generally in cell viability in the experimental groups. 3 or 9 times
increase in cell survival loss rate was observed at 6hr-SNP and ON-SNP groups, respectively compared to No-SNP
control group in first experiment that was done to test cell survival rate at relatively lower dose, from 0 to 50 Gy. In
second experiment X-ray dose was increased to 125 Gy. Survival loss was sharply decreased in a relatively lower dose
from 5 to 25 Gy, and then demonstrated an exponentially decreasing behavior with a convergence until 125 Gy for each
group. This observation suggests PAT effects on the cell directly by X-ray in the presence of Alg-SNP occurs within
lower X-ray dose, and conventional X-ray radiation effect becomes dominant in higher X-ray dose. The cell viability
loss of ON-SNP group was three times higher compared with that of 6hr-SNP group. In conclusion, it is possible to
design photodynamic X-ray therapy study using a monochromatic x-ray energy and metal nanoparticle as x-ray sensitizer,
which may enable new X-ray PDT to disseminated tumors without side effects to normal surrounding tissue.
|
