الفهرس 
TitleOnly 14 pages are availabe for public view
 |  | from | 98 |  |  |
| | | from | 98 | | |
Abstract
The aim of the present study was to evaluate the toxicity of silver and copper
nanoparticles prepared by AC- arc discharge method as a physical method compared with
silver and copper nanoparticles chemically prepared on normal liver tissues of mice.
To achieve our target, silver and copper nanoparticles were prepared by the AC- arc
discharge method and chemical reduction method. The AC- arc discharge method in pure
water at initial voltage of 68V, peak current 120 A, On-pulse duration for 2-3 S, Off-pulse
duration for 1-2 S and fabrication time was 15 min resulted in fabrication of silver and
copper nanoparticles with production yield 152 and 139 mg/min; respectively. The
prepared silver and copper nanoparticles by the AC- arc discharge method and chemical
method were characterized in terms of particle size by particle size analyzer, morphology
by transmission electron microscope, charge by zeta potential and structural analysis using
fourier-transform infrared spectroscopy (FTIR) and SEM- energy disperstitve X-ray
(SEM-EDX). Examination by the transmission electron microscop revealed that the
prepared particles by arc discharge method and chemical method were spherical in shape
and showed low level of agglomeration among particles and high level of uniformity. The
results of particle size analyzer for both silver and copper particles prepared by arc
discharge method showed that the average radius of prepared silver particles was 45.6 nm
and 38.19 nm; repectively. The charge distribution of the these particles revealed that the
zeta potential for silver nanoparticles was - 33.9 mv ± 6.87 and that for copper
nanoparticles was – 34.5 mv ± 5.86. The Optical properties as demonstrated by UV-Visble
absorption spectra of the samples indicated a strong absorption peak at 425 nm for silver
nanoparticles and 540 nm for copper nanoparticles prepared by arc discharge method.
Silver nanoparticles prepared by citrate reduction method have mean particle size
diameter of 82.87 nm and copper nanoparticles prepared using ascorbic acid as a reducing
agent showed mean particle size of 97.14 nm. the zeta potential of the silver nanoparticles
was - 37.3 mv ± 4.8 and that for copper nanoparticles was - 35.1 mv ± 7.88. The
suspension of silver and copper nanoparticles has a strong absorption maximum at 425 nm,
550 nm; respectively.
For the evaluation of the toxic effect of prepared nanoparticles, seventy five 75 male
swiss albino mice were divided into five main groups, each group consisting of 15 mice:
group I: mice received intraperitoneal injection of a suspension of saline and
serve as control group.
group II: mice received intraperitoneal injection of a suspension of physically
prepared silver nanoparticles.
group III: mice received intraperitoneal injection of a suspension of chemically
prepared silver nanoparticles.
group IV: mice received intraperitoneal injection of a suspension of physically
prepared copper nanoparticles.
group V: mice received intraperitoneal injection of a suspension of chemically
prepared copper nanoparticles.
The selected doses of silver nanoparticles (AgNPs) (500 mg/Kg) and copper
nanoparticles (CuNPs) (250 mg/Kgl) were intraperitoneally administrated day by day for
21 days (Figure 10). Prior dosing, mice were weighed and each dose of AgNPs or CuNPs
was calculated in accordance with the animal’s weight. Then mice were weighed again at
7, 14 days after treatment and at the end of the study at day 21.
In order to test the toxic effect of prepared nanoparticles, serum levels of total antioxidant
status (TAS) , Malondialdehyde (MDA), liver enzymes (AST &ALT) were investigated.
Also, animal weight and white blood cell counts were used as general marker of toxicity.
Relative liver weight was calculated according to weight of each mouse and sign of
toxicity and survival were recorded for each mouse in each group.
The toxicity study revealed:
Mice of control group were alive throughout the dosing period of 21 days, while
1 mouse (6.66%) of mice treated intraperitoneal with AgNPs- prepared
physically. 2 mice (13.3%) of mice treated intraperitoneal with AgNPs- prepared
chemically and CuNPs- prepared physically. On the other side, 7 mouse (46.6%)
mice treated intraperitoneal with CuNPs- prepared chemically.
Kaplan–Meier survival curves for analysis of survival time showed that the
mean survival time of mice treated with AgNPs chemically prepared
demonstrated mean survival time of 19.53±4.033 days, while mice treated with
AgNPs physically prepared showed mean survival time of 20.67±1.29 days
compared with the mean survival time (21 days±000) in the control group.
While at the same time for groups injected with CuNPs chemically prepared
showed mean survival time of 14.84±6.94 days and that for mice injected with
CuNPs physically prepared showed mean survival time of 20.00±2.70 days
compared with the mean survival time (21 days±000) in the control group.
All animals treated with nanoparticles chemically prepared showed decreased
WBCs compared with control group and groups administrated nanoparticles
physically prepared. Animals treated with nanoparticles physically prepared
showed decreased WBCs count compared with control group and significantly
increased compared with animals treated with nanoparticles chemically
prepared.
Both chemically and physically produced nanoparticles caused a significant
decrease in TAS level, increased MDA level and increased liver enzymes
activity when compared to control group (p <0.05). Nanoparticles physically
prepared showed a significant increase in TAS level and decreased MDA level
when compared to nanoparticles chemically produced.