Page 148 - Bio Engineering Approaches to Cancer Diagnosis and Treatment

146 CHAPTER 6 Laser-assisted cancer treatment

Being able to convert NIR light to heat, various materials have been reported
include gold-based nanoparticles, carbon-based nanoparticles, metal-based nanopar-
ticles, indocyanine green dye, polyaniline, melanin the main of which already
described in Section 6.2.
In PT-NIRSRS, graphene oxide is more appropriate than graphene owing to the
feasibility of drug-graphene oxide interaction and improve dispersibility. Also, sur-
face modification of graphene oxide by polymers not only improves sustainability but
also decrease cell toxicity as well. In 2017, multifunctional graphene oxide nanopar-
ticles were synthesized to study the synergistic effect of chemo-gene and PTT by
Zang et al. The PEGylated graphene oxides conjugated folate receptor was utilized to
load both siRNA and doxorubicin. NIR irradiation not only exhibited cell toxicity but
increased both gene and drug release as well [62]. In another study, graphene oxide
was modified by polyglycerol to load curcumin [63]. Their nanoparticles exhibited
excellent dispersibility, on-demand curcumin release during NIR irradiation and effi-
cient chemo-photothermal therapy on MCF7. Owing to the presence of carboxylic
and hydroxylic groups on its surface, graphene oxide has the potential to apply for
multisensitive systems. In 2017, graphene oxide functionalized chitosan-PEG was
synthesized to prepare both pH and NIR responsive system [64]. Due to its flexibil-
ity, graphene oxide is used as a coating. The nanohybrid composition of liposome
and graphene oxide was prepared by layer by layer deposition of GO and graphene
conjugated poly(l-lysine) (GO-PLL) on the surface of cationic liposome guided
by electrostatic interaction. When the nanohybrid exposed to NIR laser irradiation,
GO and GO-PLL functioned as a photothermal transducer and convert light to heat.
Then, it activated a solid-to-gel phase transition of the liposomes leading to release
the encapsulated toxic cargo. Their study introduced a novel pH-Thermo responsive
system for chemo-photothermal therapy [65]. The chemo-photothermal potential
effect of their nanoparticles was observed using live-dead assay under inverted fluo-
rescent microscopy, as shown in Fig. 6.5. Live cells displayed in green fluorescent
and dead cells displayed in red fluorescent. In the group treated by their nanoparticles
(named LBL Lipo-graph), before NIR laser irradiation the dead cells had to do with
chemotropic effect while after laser irradiation it was the correspondence of both
chemo and photothermal effect. As shown in Fig. 6.5, in the cells treated by LBL
Lipo-graph, dead cells increased after laser irradiation while in the control group
(treated with no nanoparticles) the number of red spots had not changed before and
after laser irradiation.
Another remarkable nanoparticle in PT-NIRSRS which already explained in
Section 6.2.5 is carbon nanotubes. Although carbon nanotubes enjoy high cross-
section absorption, high drug binding affinity and high ability to penetrate into
cells, they suffer from low dispersibility and cell toxicity. To tackle the problem,
Dong et al. conjugated TAT-chitosan to carbon nanotubes, and then doxorubicin
was loaded on its surface. Results have shown that their nanoparticles exhibited
NIR responsive properties during laser irradiation, pH-responsive behavior in the
acidic environment, improving cell internalization due to the presence of chito-
san [66].