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Article history:
Received 8 May 2016
Received in revised form 5 August
2016
Accepted 8 August 2016
Available online xxx
Keywords:
Photothermal
Gum Arabic
Gold nanoparticles
Preneoplastic lesions
Apoptosis
GST-P
ABSTRACT
This study validates the utility of Gum Arabic-conjugated gold nanoparticles (GA-AuNPs) and laser to induce photother-
mal inhibition of hepatocarcinogenesis, via employing a diethylnitrosamine (DEN)-mediated hepatocellular carcinoma
model. This work included both of in vitro and in vivo studies; to investigate the GA-AuNPs cytotoxicity and phototoxi-
city in hepatic cell line; to delineate the GA-AuNPs therapeutic efficiency in DEN-induced preneoplastic lesions (PNLs)
in the liver of Balb-C mice. The therapeutic effects of GA-AuNPs on the mediators of apoptosis, inflammation, and tu-
mor initiation, as well as the histopathological changes in preneoplastic liver have been investigated. Our results infer
that GAAuNPs in combination with laser irradiation led to a significant reduction in the cell viability and in histone
deacetylase activity in hepatocarcinoma HepG2 cells. In chemically-induced PNLs mice model our results have demon-
strated that GA-AuNPs, with or without laser irradiation, induced cancer cell apoptosis through the activation of death
receptors DR5 and caspase-3 and inhibited both of the PNLs incidence and the initiation marker (placental glutathione
S-transferase; GST-P). The laser-stimulated GAAuNPs significantly reduced the tumor necrosis factor-αlevels. In sum-
mary, GAAuNPs with laser treatment inhibited liver PNLs via the induction of the extrinsic apoptosis pathway and the
inhibition of inflammation.
© 2016 Published by Elsevier Ltd.
Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx
Contents lists available at ScienceDirect
Journal of Photochemistry & Photobiology, B: Biology
journal homepage: www.elsevier.com
Photothermal therapy mediated by gum Arabic-conjugated gold nanoparticles
suppresses liver preneoplastic lesions in mice
Amira M. Gamal-Eldeen a, b, , Dina Moustafa c, Sherien M. El-Daly a, d, Enas A. El-Hussieny e, Samira Saleh f,
Menka Khoobchandani g, h, Kathryn L. Bacon g, h, Sagar Gupta g, h, k, l, Kavita Katti g, h, Ravi Shukla i,
Kattesh V. Katti g, h, j, k, l,
aCancer Biology and Genetics Laboratory, Centre of Excellence for Advanced Sciences, National Research Centre, Cairo, Egypt
bDepartment of Biochemistry, National Research Centre, Cairo, Egypt
cDepartment of Pharmacology and Toxicology, Faculty of Pharmacy, October 6 University, 6 October City, Giza, Egypt
dDepartment of Medical Biochemistry, National Research Centre, Cairo, Egypt
eZoology Department, Faculty of Science, Ain Shams University, Cairo, Egypt
fDepartment of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
gDepartment of Radiology, University of Missouri, Columbia, MO 65212, USA
hInstitute of Green Nanotechnology, University of Missouri, Columbia, MO 65212, USA
iCentre for Advanced Materials and Industrial Chemistry; School of Applied Sciences; Health Innovation Research Institute; RMIT University, Australia
jResearch Reactor, University of Missouri, Columbia, MO 65212, USA
kDepartment of Physics, University of Missouri, Columbia, MO 65212, USA
lDepartment of Bioengineering, University of Missouri, Columbia, MO 65211, USA
1. Background
Hepatocellular carcinoma (HCC) is reported affect 500,000 people
annually [1]. Hepatocarcinogenesis is the multistep process character-
ized by several genetic variations causing aberrant growth and malig-
nant transformation of liver cells. Formation of preneoplastic lesions
(PNLs) is considered the early step in hepatocarcinogenesis, where
part of them developed through time into carcinomas [2]. Thus target-
ing these lesions can be a successful tool to prevent the development
of HCC.
Photothermal therapy (PTT), an efficient minimally invasive ap-
proach, involves photothermal sensitizers' usage that can transform
photon energy into thermal energy, which can cause irreversible cel-
lular damage, and eventually cell death. For PTT applications, the ab-
sorption band for the nanoparticle (NP) sensitizers is preferred in the
Corresponding authors.
Email address: aeldeen7@yahoo.com (A.M. Gamal-Eldeen )
near-infrared region (NIR > 700 nm) to enhance the light penetration
into tissues [3].
Nanotechnology is an uprising area of research that is intensively
applied nowadays in the medical field. Gold nanoparticles (AuNPs)
have been actively used in PTT [4], where in the presence of NIR ra-
diation, AuNPs produce what is known as plasmon resonance effect
(PR) where NPs can absorb and scatter light of wavelengths larger
than that of NPs and thus causing a localized heating. This local heat-
ing would cause tumor tissue damage and/or release of payload mole-
cules of therapeutic importance. The frequency of PR mainly depends
on the nanoparticle size and shape [5,7]. The efficiency of AuNPs
as PPT is mainly depending on the size, shape and physical proper-
ties of these nanoparticles. Nanospheres, nanorods, nanoshells, nanos-
tars, and nanocages have all been reported as subtypes of AuNPs [5].
AuNPs are carriers and enhancers of specific photoactive functional
groups to achieve effective penetration across cancer cell membranes.
The versatile surface chemistry and unique photophysical character-
istics of AuNPs providing a building block for multifunctional
http://dx.doi.org/10.1016/j.jphotobiol.2016.08.009
1011-1344/© 2016 Published by Elsevier Ltd.
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2 Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx
nanoplatforms for PTT applications. AuNPs can be conjugated to bio-
logically active moieties for effective localized therapy at tumor sites
[79]. We have successfully developed a new generation of hybrid
AuNPs that demonstrated their cancer cell-targeting features for tu-
mors molecular imaging and therapy using tumor specific nanoprobes
[7].
We are currently interested in the utility of Gum Arabic (GA) en-
capsulated AuNPs (GA-AuNPs) as potential PTT probes, since the
highly branched polysaccharide structure of GA consisting of a com-
plex mixture of glycoproteins encompassing arabic acid, with residues
of rhamnose, glucuronic acid, galactose, and arabinose, which may
promote GA-AuNPs adhesion to the cell surface proteins and max-
imize its photothermal effects [10]. GA had FDA-approval for hu-
man consumption [10]. GA application to achieve in vitro and in
vivo stability for Au and iron oxide NPs were established for imag-
ing and therapy [11], however, PTT of GA-AuNPs has remained rel-
atively unexplored. We herein aim to delineate the photothermal ef-
ficiency of GA-AuNPs on the PNLs in the early stage. Our investi-
gations included both in vitro and in vivo studies; to investigate the
GA-AuNPs cytotoxicity and phototoxicity in hepatic cell line; to de-
lineate the GA-AuNPs therapeutic efficiency in diethylnitrosamine
(DEN)-induced liver PNLs in Balb-C.
2. Materials and Methods
2.1. Synthesis of Gum Arabic Encapsulated AuNPs (GA-AuNPs)
GA conjugated nanoparticles were synthesized and characterized
following our standard protocol [7ce]. Briefly, 100 μL of 0.1 M
NaAuCl4aqueous solution was added to 6 ml of 12 mg GA aqueous
solution, stirred at 80 °C for 10 min. To this mixture, 40 μL of 0.1 M
aqueous solution of reducing agent, P(CH2NHCOOH)3(THP-Gly;
also referred to as Kattipeptide) [10] was added. Immediately af-
ter, the color changed from yellow into a ruby red, which indicated
NPs formation. The metallic core size of GA stabilized AuNPs is
21 ±6 nm (Fig. 1ac). By dynamic light scattering instrument (Ze-
tasizer Nano S90, Malvern Instruments Ltd., USA), the GA-AuNPs
hydrodynamic size was found to be 78 ±4 nm thus confirming the
GA encapsulation of AuNPs. GA-AuNPs has a negative zeta potential
(− 35.5 ±3 mV), an indication of significant in vitro stability [7]. Sta-
bility measurement that.
involved dilutions in aqueous media, saline, PBS buffer and hu-
man serum albumin have confirmed that GA-AuNPs are robust under
in vitro profiles for potential biomedical applications (Fig. 1d).
2.2. In vitro Application
Human HCC cell line (HepG2; ATCC, Rockville, MD, USA) were
routinely cultured in RPMI 1640 medium containing 10% fetal bovine
serum (FBS), 2 mM L-glutamine, 100 units/ml penicillin, and 100 μg/
ml streptomycin. Cells were cultured in a CO2incubator at 37 °C,
under humidified environment. Diode laser (Quanta System, Milan/
Italy) emitting continuous wave of light was utilized. All in vitro ex-
posures were performed in these conditions: wavelength 807 nm [11],
average power 500 mW, beam diameter 3.0 cm and power density
50 mW/cm2. The time period of exposure was 10 min. The laser light
was coupled with monocore optical fiber, and the use of a biconvex
lens ensured homogeneous exposure of the 96-well plate.
2.3. Cell Viability Assay
To evaluate the phototoxicity as well as the cytotoxicity of GA
and GA-AuNP in the presence or absence of laser irradiation, 3,4,5-di-
methylthiazol-2,5-diphenyl tetrazolium bromide (MTT) cell viabil-
ity assay was applied. HepG2 cells were cultured in 96-well plate
(0.5 ×10 [4] cells/well) for 24 h, and then treated for 24 h with in-
creasing concentrations of GA or GA-AuNP solutions, followed by a
10 min laser exposure. After 24 h, cells were submitted to MTT assay.
2.4. Estimation of Histone Deacetylase Activity
The activity of histone deacetylase (HDAC) was measured in
HepG2 cell lysate by colorimetric kit (BioVision, USA) according to
the manufacturer's instructions. HepG2 cells were treated with GA
(57.7 μg/ml) or GA-AuNP (8.6 μg/ml) with or without laser exposure.
3. In vivo Anti-Neoplastic Experiments
Animal experiments were performed adhering to the Ethical Com-
mittee guidelines of the National Research Centre, Egypt, and the Na-
tional Institutes of Health, USA, for the animal care and use. Male
wild-type Balb-c mice (1820 g; 4 weeks old; Theodor Bilharz in-
stitute, Cairo, Egypt) were housed in a 12 h light-dark cycle, with
free access to sterilized standard chow and water ad libitum. Mice
were allowed to acclimate for 7 days prior to experiments. Hepatic
PNLs were developed in mice using DEN, as previously described
by Kushida et al. [12]. A total of 224 mice were randomly subdi-
vided into two large groups: 1. Normal group (PNLs-free group, con-
trol) were subdivided into 6 subgroups (n= 16/group) including con-
trol untreated group, laser-, GA-, GA + laser-, GA-AuNPs,
GA-AuNPs + laser- treated groups. 2. PNLs-induced group
(PNLs-bearing group, n= 112 mice) received an intraperitoneal (IP)
injection of DEN (50 mg/kg b. wt.) every 2 weeks for a total of
12 weeks. At that point, three mice were randomly assigned for a
histopathological examination to check hepatic PNLs. After confirm-
ing PNLs occurrence, PNLs- bearing mice were classified into 6
subgroups (n= 16/group) including DEN (positive control),
DEN + Laser, DEN + GA, DEN + GA + Laser, DEN + GA-AuNPs,
and DEN + GA-AuNPs + Laser.
Mice received either an intravenous injection of GA (0.2 mg/
100 μl/mouse) or GA-AuNP (30 μg/100 μl/mouse) with or without
10 min laser exposure. The laser source used was the same one used
in the in vitro study but with an average power of 5 W. The laser
energy was delivered to the treatment site in a non-contact mode
from the skin surface, where the left region of the mouse abdomen
were irradiated by for a single 10 min session. Mice were gross-ob-
served for 4 weeks for any clinical signs. Individual body weights
were recorded in day 0 and every week. Weight loss > 20% was con-
sidered unacceptably toxic. After 4 weeks, mice were anesthetized;
blood was withdrawn and the plasma was separated. The livers were
excised, rinsed multiple times in ice cold PBS. A liver part was pre-
served in 4% paraformaldehyde/PBS for histopathological examina-
tion, and another liver part (40 mg) was homogenized by grinding in
liquid nitrogen and lysed in 1 ml ice-cold lysis buffer (50 mM Tris
pH 8, 150 mM NaCl, 1% Triton X-100, 0.1% sodium dodecyl sul-
phate, 0.5% Na-deoxycolate monhydrate and protease inhibitor cock-
tail tablet), and then the lysate was centrifuged at 13,000gat 4 °C for
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Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx 3
Fig. 1. a. UVvisible absorption spectra of GA-AuNPs dissolved in serum-free RPMI 1640 media; b. Transmission electron microscopy image of GA-AuNPs; c. Histogram of par-
ticles distribution; d. In vitro stability of GA-AuNPs in various biological fluids as confirmed by UVVIS absorption spectra. Cytotoxicity at different concentrations of GA and (e)
GA-AuNPs (f) against HepG2 liver cells in the presence (triangle-line) and absence (circle-line) of laser irradiation, using MTT assay. Data was expressed as mean ±S.E. of the
percentage of control cells (n= 6). g. Effect of GA and GA-AuNPs with and without laser irradiation on HDAC activity in HepG2; data expressed as μM deacetylated substrate/mg
protein.
15 min. The supernatant was stored at − 80 °C until used for biochem-
ical analyses.
3.1. Histological, Histochemical and Immunohistochemical Analyses
Unbiased histopathological examination (blind to treatment) was
performed on the sections of Paraffin-embedded tissues, by hema-
toxylin and eosin (H & E) staining. To evaluate the cell death mode,
liver tissue sections were stained with a dual DNA dyes; acridine
orange (AO) and ethidium bromide (EB) mixture (100 μg/ml) [13].
Images were captured under fluorescent microscope (Axiostar plus,
Zeiss, Goettingen, Germany) and digital camera (PowerShot A20,
Canon, USA). PCNA is a valuable marker for evaluating the cel-
lular proliferative activity. PCNA and Placental form of glutathione
S-transferase (GST-P) were detected in liver sections by immunohisto
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4 Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx
chemical analysis, using fluorescence icothiocyanate (FITC) conju-
gated antibodies.
3.2. Evaluation of Inflammation and Apoptosis Mediators
Liver tissue level of tumor necrosis factor-α(TNF-α) was quanti-
fied using Sandwich ELISA technique [14]. Levels of Cytochrome C
in tissue homogenates was measured using a commercial quantitative
ELISA kit (Abcam #154471, USA), using the manufacturer's proto-
col. The levels of caspase-3 and death receptors (DR4 and DR5) in the
tissue homogenate were measured by indirect ELISA [15].
3.3. Statistical Analysis
The data obtained from different experiments were analyzed by
(SPSS) program version 11, using one way ANOVA test/Tukey's
Post Hoc. Data were expressed as mean ±SD. Significant was se at
p< 0.05.
4. Results
4.1. In Vitro Experiments
Analysis of HepG2 cell viability after being treated with GA or
GAAuNPs revealed that, without laser irradiation, both GA
(9.057.7) μg/ml and GA-AuNPs (1.68.6 μg/ml) did not induce any
cytotoxicity. Treating cells with GA followed by laser session did not
induce cell death even at high concentration (57.7 μg/ml), while in
case of GAAuNPs, laser irradiation induced cell death, where the vi-
ability decreased to 62% at concentration of 8.6 μg/ml. The IC50 of
GAAuNPs/laser was calculated and found to be 11.7 μg/ml (Fig. 1e
and f). The results indicated that the only significant change in HDAC
activity was detected in HepG2 cells treated with GAAuNPs/laser
(p< 0.05). The other treatment modalities showed no significant re-
duction in HDAC activity (Fig. 1g).
4.2. In Vivo Experiments
4.2.1. Histopathological Examination
Liver sections of the normal groups (control untreated, laser, GA,
and GAAuNPs) showed a normal histopathology structure of hepatic
lobule. However normal mice treated with GA + laser showed slight
activation of kupffer cells. In mice treated with GA-AuNPs + Laser
showed slight cholangitis, as shown in (Fig. 2). In hepatic PNLs-in-
duced groups (DEN, DEN + Laser, DEN + GA and
DEN + GA-AuNPs) the histopathological examination showed kary-
omegaly of hepatocytic nuclei, cholangioma and oval cells, hyper-
plasia, as well as a significant kupffer cells proliferation with por-
tal infiltration. Hepatic PNLs were induced, in mice that were treated
with DEN + GA + laser, with hepatocytomegaly, karyomegaly and fo-
cal hepatic necrosis that was associated with inflammatory cells infil-
tration. DEN + GA-AuNPs-treated mice showed oval cells hyperpla-
sia and significant induction of apoptotic hepatocytes and inhibition of
PNLs (Fig. 2).
4.2.2. Apoptosis and Necrosis Analysis
Another morphologic evaluation was carried out by dual DNA
staining by AO/EB. All normal groups showed high predominance
of viable cells of organized structure green nuclei, however slight
morphological changes GA-AuNPs mice with/without laser were ob-
served, where few cells with bright green to orange staining were
detected indicating early to late apoptosis (Fig. 3). In PNLs-induced
groups, the important morphologic change observed was in
GA-AuNPs or GA-AuNPs + laser, where a high incidence of early
apoptosis (bright green cells) and late apoptosis (cells of condensed
and fragmented yellow to orange chromatin) was predominant. It is
also important to mention that in PNLs-induced mice treated with
GA-AuNPs + Laser, although the majority of cells were in the late
apoptotic state, we also observed few necrotic cells displaying orange
to red nuclei (Fig. 3).
4.2.3. PCNA Detection
PCNA is considered as an index of the cell turnover rate, as it is
associated with S phase and DNA replication in the cell cycle. The
PCNA positive cells and colonies appeared as bright green stained
solitary cells or regions. Undetectable PCNA-positivity was noticed in
all of the normal groups (Fig. 5). On the other hand, nuclear staining
of PCNA was highly detected in all PNLs-induced groups (p< 0.05),
an indication of the high proliferative activity of the cells. However,
in the two PNLs-induced groups that were treated with GA-AuNPs
with/without laser showed a significant suppression in PCNA activity
comparing to the DEN group (Fig. 5). These findings pointed out the
probability that GA-AuNPs alone can halt the cell proliferation even
without laser stimulation.
4.2.4. GST-P Positive Foci
GST-P is known as a carcinogen detoxification enzyme and it is
one of the most reliable markers for tumor initiation. In the present
study, all of the normal groups showed morphologically normal cells
with no positive staining of GST-P (Figs. 4, 6). On the contrary, the
expression of GST-P was markedly detectable in all PNLs-induced
mice and was obviously in strong GST-P positive foci. However a
significant reduction (p< 0.05) in the GST-P positive foci was de-
tected in the PNLsinduced groups received GA-AuNPs with or with-
out laser exposure (Figs. 4, 6).
4.2.5. Estimation of TNF-
α
A significant elevation of TNF-αconcentration that was observed
in all of PNLs-induced groups comparing with normal groups. In the
PNLs groups treated with GA-AuNPs with/without laser exposure, a
noticeable reduction in TNF-αconcentration was found compared to
DEN group (Fig. 6).
4.2.6. Apoptosis Mediators
The level of Cytochrome-c, a responsible trigger of intrinsic apop-
tosis, showed no significant change in all groups with different treat-
ment modalities (data not shown). However in the case of other apop-
totic mediators (caspase-3, DR4 and DR5), the significant changes
(p< 0.05) were detected in caspase-3 and DR5 levels in all of
GA-AuNPs-treated groups (healthy and PNLs-induced groups with/
without laser), which is another indication that treatment with
GA-AuNPs alone have an apoptotic effect on cells (Fig. 7).
4.2.7. Discussion and Conclusion
GA is regarded as an alternative biopolymer for the coating and
stabilization of nanostructures including iron oxide, magnetic NPs
[16,17,18], AuNPs [10,18d] and as a PT agent [19]. In the present
study aimed to validate the hypotheses that AuNPs conjugated with
GA matrix are effective probes for the use in PTT, we have used
GA-AuNPs produced by the reduction of Au salt with a water soluble
trimeric glycine-phosphine (P(CH2NHCOOH)3). This novel reducing
agent was discovered in our laboratory [11]. Detailed procedures for
the synthesis of a large NPs variety have been described using simi-
lar family of NPs initiators [7]. These GA-AuNPs have optimum sizes
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Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx 5
Fig. 2. Representative photos for H&E stained liver sections from different mice groups (×400).
(Fig. 1c) and favorable in vitro stabilities for potential applications un-
der in vivo profiles (Fig. 1d) [7]. The negative zeta potential value of
GA-AuNPs provides the necessary repulsive forces resisting particles
agglomeration and therefore stay stable in different solutions and ex-
pected to have long-term in vitro and in vivo stability of the nano-par-
ticulate dispersions.
Since rod-shaped AuNPs, among other structures, revealed a
higher PTT than sphere-shaped AuNPs, we planned to use GA to
prepare rod-shaped AuNPs in the future studies. In the present study
we investigated the PPT for the successfully prepared sphere-shaped
GA-AuNPs. It is known that the spheres size of is more efficiently
taken up by cells than the nanorods shape, moreover spheroid AuNPs
are characterized by the ease and fast method of preparation compar-
ing to other nanostructures [6]. In previous report, NIR at 540 nm [5]
and at 800 nm [11] were used to stimulate PTT in spheroid AuNPs.
Huang et al. [11], who prepared spheroid AuNPs of similar diame-
ter size and similar surface plasmon absorption intensity (540 nm) and
reported that NIR at 800 nm enhanced the second harmonic genera-
tion and the two photon absorption. They also found that the use of
800 nm to irradiate AuNPs spheres had increased the photothermal
destruction effect of AuNPs on the cells. Accordingly, in this study,
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6 Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx
Fig. 3. Representative images for the analysis of cell death type in liver sections from different mice groups, as stained by AO/EB and captured under fluorescence microscope
(×200), showing living cells (green), early apoptotic cells (bright green nucleus with condensed/fragmented chromatin), late apoptotic and necrotic cells (condensed/fragmented
chromatin; dark orange). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
we preferably selected NIR laser 800 nm to enhance the PTT effi-
ciency of AuNPs.
In order to prove the GA-AuNPs stability at appropriate concen-
trations for cellular dilutions, we have performed dilution studies
and estimated stability by monitoring the plasmon resonance wave-
length after every successive addition of 0.1 ml in doubly ionized
water through additions to 1 ml of GA-AuNPs solutions. Our results
have confirmed that absorption intensity of AuNPs (540 nm) did not
change even at very dilute conditions. It is, thus, conceivable that the
encapsulation of AuNPs by GA phytoconstruct is aiding the stabi-
lization in aqueous media, involving saline, PBS buffer, serum albu-
min solutions and different other buffers, as a biologically relevant
medium and at concentrations optimum for biomedical applications
(Fig. 1D). Our next goal of this study was to evaluate the cytotoxicity
of GA-AuNPs with or without laser exposure on a hepatic cell line (in
vitro study), and then to study GA-AuNPs potential anti-preneoplastic
effect in hepatic preneoplastic-induced mice model.
Our studies have revealed that various concentrations of both GA
and GA-AuNPs (without laser exposure) were safe and did not in-
duce any cytotoxicity in HepG2 cells. This finding is in accordance
with previous reports, which found that using gold nanospheres (4,
12, and 18 nm in diameter) with stabilizing capping agents (cysteine,
glucose, citrate, or biotin) for the treatment of human leukemia cells
caused no cell death [18d,20,21]. However, our investigations involv-
ing the treatment of HepG2 cells with GA-AuNPs followed by laser
irradiation resulted in a remarkable phototoxicity due to the collective
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Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx 7
Fig. 4. Representative photos for GST-P expression in liver sections from different mice groups (×400), as stained by FITC-labeled antibodies.
PT effect resulting from GA-AuNPs nanoparticulate assembled struc-
tures. Our findings corroborate results observed by Liu et al. [22],
and Richardson et al., [23] who have suggested that the PT effect of
AuNPs are due to their multiple mobile electrons, which are strongly
enhanced by absorption of incident photons of laser beam that matches
collective plasmon resonance, thus resulting in efficient conversion
of photon energy into heat energy. This heat energy in close prox-
imity to tumor cells and surrounding tumor matrix would result in
effective tumor therapy through the excess heat energy transferred.
The phototoxic effect of GA-AuNPs on HepG2 cells was also medi-
ated by a significant reduction in the HDAC activity, suggesting that
these NPs, in addition to their repressor proliferation effect, can also
show a post-translational modification of DNA histone proteins. This
is in accordance with other studies, where Sule et al. [24], suggested
that AuNPs can bind to the sulfhydryl groups on the surface of his-
tone deacetylase and thus repress its activity. Mazumder et al. [25], re-
ported that AuNPs considered as epigenetic modulator by modifying
chromatin connections with lamin proteins and core histones.
As part of our extensive evaluation of PT effect of GA-AuNPs
on tumor initiation, we have induced hepatic preneoplastic lesions in
mice using the DNA alkylating agent DEN [26]. The histopathologi-
cal examination of liver tissues harvested after the different treatment
modalities revealed that the administration of GA or GA-AuNPs or
exposure to laser separately resulted in no histopathological change,
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8 Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx
Fig. 5. Representative photos for PCNA expression in liver sections from different mice groups (×400), as stained by FITC-labeled antibodies.
thus confirming the safety of both. Al-Kenanny et al., [27] had re-
ported the safety of GA when used in liver injury induced by gen-
tamycin. El-Sayed et al. [28], had reported the safety of NIR laser us-
age and observed that the viability of cancer cells was not affected
when exposed to different laser power density (19, 25, 38, 50, 64,
or 76 W/cm2) for 4 min using CW argon laser. Both studies [27,28]
are confirming the safety of each treatment modality when using sep-
arately, accordingly the therapeutic effect was due to laser-stimu-
lated AuNPs. Administration of GA-AuNP and subsequent exposure
to laser irradiation resulted in massive apoptotic cancer cell death
as noted from the histopathological examination. This was also sup-
ported from AO/EB staining (Fig. 3), which demonstrated that treat-
ment with GA-AuNPs induced apoptosis to some extent without laser
exposure but when it is combined with irradiation, apoptosis was
predominant with few necrotic cells. Activation of apoptosis is the
sole determinant of most of the effect anti-tumor strategies. Apopto-
sis involves two distinct pathways, the extrinsic (death receptor) path-
way, which begins with the binding of an appropriate ligand to a
subset of death receptors (such as Fas, TNF, DR3, DR4, DR5) [29]
and the intrinsic (mitochondria mediated) pathway, which is initiated
when cells are exposed to severe oxidative stress and hypoxia result-
ing in an elevated mitochondrial permeability with consequent release
of pro-apoptotic molecules such as cytochrome-c into the cytoplasm
which in turn initiate apoptosis [30]. In the extrinsic pathway, activa-
tion of death receptors is followed by the formation of a death-induc-
ing signaling complex (DISC). Binding of the initiator caspase 8 to
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Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx 9
Fig. 6. (a) Number of GST-P positive cells in liver sections from different groups, as stained by the corresponding FITC-labeled antibody. Sections were imaged and analyzed by
image analyzer. (b) TNF-αconcentration in liver homogenate of different groups, as measured by sandwich ELISA.
the DISC resulted in an activation of the downstream effector cas-
pase-3 and initiate the extrinsic apoptotic program [31]. This mech-
anism was in accordance with our findings, where the detected ele-
vation of apoptosis after GA-AuNPs treatment was also accompanied
by a significant increase in the levels of DR5 and caspase-3. Liu et
al. [22] reported that Au-AuNPs conjugated with GA may strongly
interact with asialoglycoprotein receptors of hepatocytes due to the
presence of arabinogalactan in GA. Asialoglycoprotein receptors are
known to mediate recognition of apoptotic hepatocytes by their viable
neighbors [32]. Therefore, we infer that GA-AuNPs, in our present in-
vestigation, may interact with the asialoglycoprotein receptors of he-
patocytes, thus in turn enhanced the DR-5 up-regulation and activate
caspase 3, resulting in apoptosis enhancement.
In our endeavor to delineate the inhibitory effects of GA-AuNPs
on the neoplastic process in the liver, we evaluated the positive stain-
ing of GST-P foci. The protein content of GST-P in preneoplastic cells
is exceedingly high, comprising > 1% of the soluble cytosolic pro-
teins and therefore has permitted identification and evaluation of ini-
tiation stage of carcinogenesis [33]. Our investigations have inferred
that hepatocytes of normal groups showed no GST-P positive foci,
which is in accordance with other studies [33]. However, mice sub-
jected to DEN administration showed hyperplastic liver nodules with
strong positive staining of GST-P indicating the presence of hepato-
cellular foci, this finding further corroborate earlier observations of
Ledda-Columbano et al. [34], and Perra et al. [35], who also reported
that DEN administration increased the number of induced GST-P pos-
itive cells. These hyperplastic nodules can easily progress into HCC,
indicating that the high GST-P + expressing hyperplastic liver nod-
ules serve as cancer precursors [36]. The observed significant attenu-
ation in the growth of hepatic pre-neoplastic foci positive for GST-P,
as shown in Figs. 4 and 6a, upon treatment with GA-AuNPs with or
without laser exposure, provide a solid rationale that these NPs have
an inhibitory effect on tumor initiation.
Neoplastic process is often associated with chronic inflammation
[37], therefore we have considered the effects of GA-AuNPs on in
flammatory mediators. In the present study, the chronic inflammation
state in all PNLs-induced mice was proved by the enhanced TNF-α, as
a result of DEN administration [38], which was significantly reduced
upon treatment with GA-AuNPs. Functionalized AuNPs have been
reported in several studies to cause significant reduction in the ex-
pression of different inflammatory mediators with consequent attenu-
ation in the local macrophages production of TNF-αand IL-6 [39,40].
Meanwhile, it is also reported that GA protein alone has anti-inflam-
matory effects due to suppression of leucocytes infiltration, which is
considered to be a source of inflammatory mediators [41]. In tradi-
tional medicine GA is used as a treatment for the intestinal mucosa
inflammation [42]. Taken together the previous reports and our own
findings, it appears that the anti-inflammatory effects of GA-AuNPs
(even in the absence of laser irradiation) may presumably be due to
the combined effects of AuNPs and GA. The in vitro and the in vivo
findings from our current investigations corroborate an important con-
clusion that the functionalized GAAuNPs are efficient PTT agents as
they have demonstrated efficacy in inhibiting liver PNLs and inflam-
mation via induction of the extrinsic pathway of apoptosis.
Conflict of Interest Statement
The authors declare no conflict of interest.
Acknowledgements
We are grateful to laser Research Unit, NRC, Egypt, in particu-
lar Prof. Dr. Ali Shabaka for their efforts. This work was financially
supported by October 6 University and the National Research Centre,
Cairo, Egypt. We thank the University of Missouri for intramural sup-
port through University of Missouri Interdisciplinary Intercampus Re-
search Program (IDIC), funded by UM System and the MU campus.
Ravi Shukla acknowledges the generous VC research fellowship sup-
port from RMIT University.
UNCORRECTED PROOF
10 Journal of Photochemistry & Photobiology, B: Biology xxx (2016) xxx-xxx
Fig. 7. (a) Caspase-3, (b) DR4 (black bars) and DR5 (light gray bars) were measured in
liver homogenate of different groups by ELISA. Data was expressed as the mean ±SE
of absorbance readings. Statistical analysis was carried out. The bar labels; a: p< 0.05
comparing with untreated group, and b: p < 0.05 comparing with DEN-treated group.
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... This approach has significant superiority compared to other non-chemical based approaches including the application of bacteria, fungi [28], and algae [29] for the production of nanoparticles. Pioneering work by Katti et al. demonstrated that phytochemicals from soy, tea, cumin, cinnamon, grapes and mango can be used to produce well-defined tumor specific gold nanoparticles through 100% nontoxic methods [6][7][8][9][10][11]17,[30][31][32][33][34][35][36][37][38][39][40]. Green nanotechnology processes combine all the advantages of traditional green synthetic processes and often enjoy additional benefits of being fast, low cost as they utilize byproducts from the agricultural produce and ensure environmentally friendly features as well [41][42][43][44][45][46][47][48][49][50][51][52]. ...
... Katti's group have pioneered the development of innovative synthetic techniques based on the principles of green technology over the past two decades [7,27,30,31,[34][35][36][37]40,65,[82][83][84]. Their overarching objective for introducing the concept of 'Green Nanotechnology' has been to minimize or eliminate the application of toxic chemicals as reducing/stabilizing agents for the transformation of metallic precursors to their corresponding nanoparticles. ...
... Plants are widely used for the green synthesis of AuNPs. Sources of electron-rich phytochemicals include leaf extracts from plants [6][7][8][9][10][11]17,[30][31][32][33][34][35][36][37][38][39][40]102], whole plant extracts, seed extracts, flower extracts, fruit extracts, etc.-all of which are employed as reducing agents to synthesize AuNPs. Furthermore, these nanoparticles can also be stabilized using natural stabilizing agents such as gum arabic-a protein from acacia tree [65]. ...
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In this review, we focus on recent advances in green nanotechnology, providing details on reliable synthetic pathways towards biocompatible and medically relevant gold and radioactive gold nanoparticles. We cover a wide plethora of synthetic protocols that utilize green nanotechnology with in-depth understanding of what makes a green process green. In section 2, we provide full details on the intervention of green nanotechnology for the production of various functionalized gold nanoparticles (AuNPs). Section 3 focuses on various characterization tools to be used for the complete physicochemical, size and in vitro characterization of gold nanoparticles before translating them into potential in vivo applications. Section 4 focuses on the science and applications of gold nanoparticles in diagnostic imaging. Specifically, we have highlighted the importance of the chemistry and physics of gold nanoparticles for applications in a myriad of diagnostic imaging including X-ray contrast agents, in single photon emission computed tomography (SPECT) imaging, positron-emission tomography (PET) imaging, optical coherence tomography (OCT), fluorescence imaging, magnetic resonance imaging (MRI), in surface enhanced Raman spectroscopy (SERS), and in ultrasound (US) imaging. Section 5 discusses latest advances on gold nanoparticles in drug delivery, gold nanoparticles in photothermal therapy and radioactive gold nanoparticles in cancer therapy. In particular, we discuss green nanotechnological interventions on how the electron rich phytochemicals including epigallocatechin gallate (EGCG) from tea, mangiferin (MGF) from mango and allied phytochemicals can be utilized in their dual roles, as reducing agents as well as rendering tumor specificity due to their strong tumor cell receptor avidity—to produce tumor specific molecular imaging and therapy agents. We also discuss latest advances on the importance of gold nanoparticles in X-ray Therapy. Important aspects relating to systemic toxicity of gold nanoparticles and ways to mitigate toxicity issues for their effective implementation in biomedical sciences are also discussed in section 6. The topics covered are intended to answer questions including why we should use green processes and what is the role of nanomedicine in the domain of human health and hygiene. Most importantly, we provide critical analysis on the ubiquitous role of gold nanoparticles in nanomedicine.
... Gold nanoparticles (AuNPs) present great biological application potential and capacity due to prolonged-release kinetics and long-term persistence at multiple, locus-specific target sites utilized in cancer therapy (Golchin et al. 2018). Among recent AuNPs studies in cancer treatment, Gamal-Eldeen et al. (2016) reported that Gum Arabic-encapsulated AuNPs (GA-AuNPs inhibited inflammation and liver preneoplastic lesions through the induction of extrinsic apoptosis pathway. Additionally, Gamal-Eldeen et al. (2017) reported that in lung tumor tissues, GA-AuNPs had induced cell death and lipid peroxidation and reduced in inflammation and angiogenesis, signifying the potential use of these functionalized AuNPs as a cancer therapeutic modality. ...
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... We previously reported GA-AuNPs as a promising candidate for cancer treatment in both in vitro and in vivo models of liver and lung cancers (Gamal-Eldeen et al. 2016. Where in vivo studies in liver cancer initiation model, demonstrated that few liver cells showed earlyto-late apoptosis in mice group treated with GA-AuNPs alone (Gamal-Eldeen et al. 2016). ...
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... In recent years, research on the synthesis of nanoparticles using "zero carbon emission" green nanotechnology has gained considerable prominence. 18,19 AuNPs production through green nanotechnology involves the application of high-antioxidant capacity phytochemicals as reducing agents to transform gold salts (Au 3+ ) into their corresponding nanoparticles (Au 0 ) encapsulated with phytochemicals. In this context, plant extracts, 20 alginate, 21 chitosan, 22 high-oxidant natural chemicals, 19 silk fibroin polypeptide 23 and starch 24 have been reported as dual reducing and stabilizing agents for the production of gold nanoparticles. ...
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Notch signaling is one of the most common drivers of carcinogenesis in many types of cancers, including hepatocellular carcinoma (HCC); however, it occasionally suppresses tumor progression. Moreover, it is virtually unknown how different sets of Notch ligands and receptors regulate the HCC development. In this study, we demonstrate that the expression of the Notch ligands, Delta-like 4 (Dll4) and Jagged-1 (Jag1), is upregulated during diethylnitrosamine-induced hepatocarcinogenesis. Dll4 is detected in the preneoplastic hepatocytes and HCC cells, but not in the normal hepatocytes, while Jag1 is expressed in the desmin-positive mesenchymal cells. Hepatocyte-specific Dll4 knockout abolishes the Notch1 signaling and suppresses the tumor progression. In contrast, Jag1 deletion induces the ectopic expression of Dll4 in hepatocytes along with the loss of Notch2 signaling, leading to the tumor progression. These results indicate that the two distinct Notch signals, Dll4/Notch1 and Jag1/Notch2, are antagonistic to each other, exerting opposite effects on HCC progression.
... In addition, GA had shown in studies its targeting specificity based on the interaction of hydroxyl groups with asialoglycoprotein receptors. Thus, this polymer has excellent potential for delivering bioactive agents as a target-oriented delivery system, functioning through receptormediated endocytosis (Gamal-Eldeen et al., 2016). ...
... In addition, GA had shown in studies its targeting specificity based on the interaction of hydroxyl groups with asialoglycoprotein receptors. Thus, this polymer has excellent potential for delivering bioactive agents as a target-oriented delivery system, functioning through receptormediated endocytosis (Gamal-Eldeen et al., 2016). ...
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The main purpose of the study was to enhance the stability and therapeutic effects of Curcumin (Cur) through nanoformulation with gum Arabic (GA) as a coating agent through an efficient synthetic approach. The antioxidant properties of the developed nanoparticles (Cur/GANPs) were assessed through several in vitro assays, such as β-carotene bleaching activity, DPPH, and nitric oxide scavenging activities in addition to evaluating its inhibitory activity on angiotensin-converting enzyme (ACE). The cytotoxicity of Cur/GANPs was evaluated in vitro using different types of human cancer cells including breast cancer (MCF7, MDA-MB231), liver cancer (HepG2), and colon cancer (HT29) cells. The prepared particles displayed an elliptical shape with a size ranging between 20-260 nm and a potential difference of-15 mV. The Cur/GANPs exhibited significant antioxidant activity compared to free curcumin when using concentrations between 31.5 and 500 µg/mL. The Cur/GANPs also had inhibited the growth of all cancer cell lines in a proportional trend with concentrations used. Hence, the encapsulation with gum Arabic has augmented the antioxidant and anti-neoplastic effects of Curcumin. Therefore, Cur/GANPs may have effective therapeutic properties in diseases attributed to oxidative stress like cancer and hypertension.
... Therefore, it is necessary to functionalize the iron hydroxide nanoparticles with a suitable surface modifier [5,9]. Recently, several researchers fabricated metal nanocomposites using different plant-based and natural biopolymers and revealed the least cytotoxicity and higher antimicrobial properties [10][11][12]. Among all biopolymers, gum arabic, due to its potential surface activity, is used as an effective surface modifier for the functionalization of metal nanoparticles [5]. ...
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Recently, the interest of scientists has turned towards eco-friendly metal nanoparticles due to their distinctive physicochemical properties that have been used in several biochemical and food applications, including drug and bioactive component delivery, sensing of food pathogenic bacteria, imaging techniques, and theranostics. Therefore, this study aimed to fabricate gum arabic stabilized iron hydroxide nanoparticles (IHNPs) using the co-precipitation process and to develop nanoparticles decorated antimicrobial cellulose paper. The agglomeration of IHNPs is a major concern, therefore, the varied concentration (0.25–2.0%) of gum arabic was used to functionalize and stabilize the nanoparticles, and based on UV-visible spectroscopy and particle size analysis, 1% gum arabic concentration was screened out. Scanning electron microscopy displayed polygonal disc shapes of IHNPs that had sides of approximately equal lengths. Energy dispersive spectroscopy was used to determine the purity of the IHNPs and results illustrated the elemental iron peak at 0.8 keV and 6.34 keV. For thermal stability, differential scanning calorimetry (DSC) was employed, and the glass transition temperature was observed at 138.50 °C with 138.31 °C onset and 147.14 °C endset temperature, respectively. Functionalized IHNPs showed a significantly (p < 0.05) higher zone of inhibition against S. aureus (29.63 mm) than that of E. coli and were found to be non-toxic to Caco-2 cells during cell viability assay. Time-kill kinetics showed that cellulose paper embedded with nanoparticles possessed excellent antibacterial activity against S. aureus. To explore the food application of developed cellulose paper, citric acid coagulated dairy product (Paneer), similar to cottage cheese was formulated, and it was evaluated for its microbial shelf life. The unwrapped sample showed higher microbial load during the fourth day of the storage. However, both wrapped samples were acceptable till the 10th of storage.
... They offer effective properties for an ideal PS [2]. They are absorbed in the red and near infrared regions of the visible spectrum [3]. In addition, Pcs have high photo and chemical stability [4]. ...
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Laser ablation synthesis in liquid solution (PLAL) is a green technique that allows for the physical formation of nanomaterials. This study indicates the preparation of stable gold nanoparticles (AuNPs) in Gum Arabic (GA) solution via laser ablation as a CT contrast agent. The optical properties were achieved using the absorption spectroscopic technique whereas the morphology and size distribution were investigated by TEM and ImageJ software. TEM image shows greater stability and spherical shape of GA-AuNPs with smaller size at 1.85 ± 0.99 nm compared to AuNPs without GA. The absorption spectrum of pure AuNPs has a lower absorption peak height in the visible range at λ = 521 nm, while the spectrum of GA-AuNPs has a higher plasmon peak height at λ = 514 nm with a blue shift towards lower wavelengths. The concentration of GA that dissolved in 10 mL of DI water via laser ablation is set at 20 mg. Increasing the number of pulses has only a minor effect on particle size distribution, which remains tiny in the nanometer range (less than 3 nm). For energies greater than 200 mJ, there is a blue shift toward shorter wavelengths. As the concentration of GA-AuNPs increases, the CT number is also increased indicating good image contrast. It can be concluded that there is a positive and significant influence of GA as a reducing agent for AuNPs, and a contrast agent for CT imaging which highlights its superiority in future medical applications.
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Introduction Gum arabic-coated radioactive gold nanoparticles (GA-198AuNPs) offer several advantages over traditional brachytherapy in the treatment of prostate cancer, including homogenous dose distribution and higher dose-rate irradiation. Our objective was to determine the short-term safety profile of GA-198AuNPs injected intralesionally. We proposed that a single treatment of GA-198AuNPs would be safe with minimal-to-no evidence of systemic or local toxicity. Methods Nine dogs with spontaneously occurring prostatic cancer were treated. Injections were performed with ultrasound or computerized tomography guidance. Complete blood counts, chemistry panels, and urinalyses were performed at weekly intervals for 1 month and imaging was repeated 4 weeks postinjection. Planar scintigraphic images were obtained within 30 minutes of injection. Results No statistically significant difference was found in any hematologic or biochemical parameter studied, nor was any evidence of tumor swelling or abscessation found in eight dogs with repeat imaging; one dog died secondary to urethral obstruction 12 days following injection. At 30 minutes postinjection, an average of 53% of injected dose in seven dogs was retained in the prostate, with loss of remaining activity in the bladder and urethra; no systemic uptake was detected. Conclusion GA-198AuNP therapy had no short-term toxicity in the treatment of prostatic cancer. While therapeutic agent was found in the prostate immediately following injection, some loss of agent was detected in the bladder and urethra. Localization of radioactivity within the prostate was lower than anticipated and likely due to normal vestigial prostatic ducts. Therefore, further study of retention, dosimetry, long-term toxicity, and efficacy of this treatment is warranted prior to Phase I trials in men.
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The goal of our study was to demonstrate the utility of nanocrystalline gold as an X-ray contrast agent for imaging tumor in living subjects. Even though significant progress has been achieved in this area by researchers, clinical translation remains challenging. Here, we investigated biocompatible gum Arabic stabilized gold nanocrystals (GA-AuNPs) as X-ray contrast agent in tumor bearing mice and dog. Single intratumoral injections of GA-AuNP resulted in X-ray contrast change of -26 HU in the tumor region after 1 hour post-injection period. Subsequently, five intratumoral injections were performed in the mice. The change in CT number in tumor region is not progressive; rather it reaches a saturation point after fourth injection. These data suggested that accumulation of GA-AuNP reaches a threshold limit within a short time period (5 h), and is retained in the tumor tissue for the rest of the period of investigation. A pilot study was conducted in a client-owned dog presented with collision tumor of thyroid carcinoma and osteosarcoma. In this study, GA-AuNP was injected intratumorally in dog and a contrast enhancement of 12 deltaHU was observed. The CT images of both mice and dog clearly demonstrated that GA-AuNP was effectively distributed and retained throughout the tumor site. The CT data obtained by the present study would provide the crucial dosimetry information for strategic therapy planning using this construct. Both mice and dog did not show any clinical changes, thereby confirming that GA-AuNP did not induce toxicity and can be explored for future clinical applications.
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Cancer is one of the dreadest diseases once diagnosed and has severe impacts on health, social and economic global aspects. Nanomedicine is considered an emerging approach for early cancer diagnosis and treatment. The multifunctional effects of silver and gold nanoparticles (Ag and Au NPs) have rendered them to be potent candidates for biomedical applications. The current work presents a comparative study between Au NPs and Ag NPs as possible potent photosensitizers (PS) in photodynamic therapy (PDT). Transmission electron microscopy (TEM) was used to identify and characterize the shape, size, and cellular localization of Au NPs; the absorption properties of Au NPs were determined using ultraviolet-visible spectroscopy (UV-Vis) and zeta potential was used to identify surface charge. Inverted light microscopy (LM), Trypan blue exclusion assay, adenosine triphosphate luminescence (ATP), and lactate dehydrogenase membrane integrity assays (LDH) were used for investigating the photodynamic ability of these nanostructures on breast (MCF-7) and lung (A549) cancer cell lines. Flow cytometry using Annexin V and propidium iodide (PI) dyes was used to determine the cell death pathway induced. The average size of the synthesized Au NPs was 50nm, having an absorption peak at 540nm with -7.85mV surface net charge. MCF-7 and A549 cells were able to absorb the Au NPs. The latter, when irradiated with laser light in the phototherapeutic window, promoted cytotoxicity and a significant reduction in cell viability and proliferation were observed. The photodynamic activity that was observed in both cancer cell lines was found to be less eminent than that observed in case of the Ag NPs when compared to Au NPs. The present study is the first that compares the photodynamic ability of two different nanoparticles, silver and gold, as photosensitizers without any further functionalization. This study extends the possibilities of using such nanostructures in PDT within the therapeutic window wavelength, yet through the conjugation of Au NPs with other photosensitizers to synergize its effect.
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Spatiotemporal control of singlet oxygen (1O2) release is a major challenge for photodynamic therapy (PDT) against cancer with high therapeutic efficacy and minimum side effects. Here a selenium-rubyrin (NMe2Se4N2)-loaded nanoparticle func-tionalized with folate (FA) was designed and synthesized as an acidic pH-activatable targeted photosensitizer. The nanoparticles could specifically recognize cancer cells via the FA-FA receptor binding and were selectively taken up by cancer cells via receptor-mediated endocytosis to enter lysosomes, in which NMe2Se4N2 was activated to produce 1O2. The pH-controllable release of 1O2 specially damaged the lysosomes and thus killed cancer cells in a lysosome-associated pathway. The introduction of selenium into the rubyrin core enhanced the 1O2 generation efficiency due to the heavy atom effect, and the substitution of dimethylaminophenyl moiety at meso-position led to the pH-controllable activation of NMe2Se4N2. Under near-infrared (NIR) irradiation, NMe2Se4N2 possessed high singlet oxygen quantum yield (ΦΔ) at an acidic pH (ΦΔ = 0.69 at pH 5.0 at 635 nm) and could be deactivated at physiological pH (ΦΔ = 0.06 at pH 7.4 at 635 nm). The subcellular location-confined pH-activatable photosensitization at NIR and the cancer cell-targeting feature led to excellent capability to selectively kill cancer cells and prevent the damage to normal cells, which greatly lowered the side effects. Through intravenous injection of FA-NMe2Se4N2 nanoparticles in tumor-bearing mice, tumor elimination was observed after NIR irradiation. This work presents a new paradigm for specific PDT against cancer, and provides a new avenue for preparation of highly efficient photosensitizers.
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Herein, one multifunctional AS1411-functionalized fluorescent gold nanoparticles (named NAANPs) is synthesized and successfully applied for both targeted cancer cell imaging and efficient photodynamic therapy (PDT). The NAANPs are obtained by functionalizing the gold nanoparticles with AS1411 aptamer and then bound with one porphyrin derivative N-methylmesoporphyrin IX (NMM). Using HeLa cells over expressing nucleolin as representative cancer cells, the formed NAANPs can target to the cell surface via the specific AS1411-nucleolin interaction, which can discriminate the cancer cells from normal ones (e.g. HEK293) unambiguously. That the fluorescence intensity of NMM increased significantly upon binding to AS1411 G-quadruplex makes the NAANPs appropriate fluorescence reagent for cell imaging. Meanwhile, NMM can also be used as a photosensitizer, thus irradiation of the NAANPs by the white light from a common electric torch can lead to efficient production of cytotoxic reactive oxygen species for establishing a new type of PDT to cancer cells. Gold nanoparticles play the roles of both carrier and enhancer of the functional groups onto the cells. In addition, they not only possess inherently certain cytotoxicity to the cancer cells, but also boost the cellular uptake of the fluorescent groups. As a result, the efficiency of both the targeted cell imaging and PDT could be ensured.
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Gold nanoparticles (AuNPs) have been established to sufficiently eradicate tumors by means of heat production for photothermal therapy. However, the translation of the AuNPs from bench to the clinic still remains to be solved until realizing high bioclearance after treatment. Herein, we developed a simple strategy for simultaneous formation and assembly of small-size gold nanoparticles (Au-SNPs) to form a novel nanocomposite in the presence of gum arabic (GA) by synchrotron X-ray irradiation in an aqueous solution within 5 min. GA, a porous polysaccharide, can not only provide a confined space in which to produce uniform Au-SNPs (1.6 ± 0.7 nm in diameter), but can also facilitate the formation of Au-SNPs@GA (diameter ≈ 40 nm) after irradiating synchrotron X-rays. Specifically, the Au-SNPs@GA possesses high thermal stability and a strong photothermal effect for killing cancer cells. Importantly, a bioclearance study demonstrated that the Au-SNPs@GA can be gradually excreted by the renal and hepatobiliary system, which might be due to the breakdown and oxidation of GA under irradiating synchrotron X-rays. Thus, the novel gold nanocomposite can be promising photothermal agents for cancer treatment at the therapeutic level, minimizing toxicity concerns regarding long-term accumulation in vivo.
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Magnetic nanoparticles (MNP) were synthesized under acidic conditions in the presence of oleylamine (OLA) and gum Arabic (GA) to study the influence of surface modification on MNP characteristics and cellular level bioactivity. Highly dispersed MNPs were formed from acidic solutions of ferric and ferrous chloride in the absence and presence of OLA. The MNP synthesized in the presence of GA formed large particle aggregates that exhibited rapid coagulation. The three types of MNP were characterized via thermogravimetric analysis (TGA), and dynamic and electrophoretic light scattering to determine particle size and zeta potential. Cytotoxicity and cell interactions were assessed for each of the three MNP samples using L929 fibroblast cells. OLA modified MNPs exhibited the highest level of cytotoxity. Approximately 27% of L929 fibroblast cells died after exposure to OLA modified MNP in comparison to 10% cell death for untreated, GA treated, and control cells. Cells that were exposed to MNPs could be translated in magnetic fields. The OLA and untreated MNPs could be detected in the cell cytoplasm while the GA-modified MNP clusters were located at the cell membrane based on light microscopy.