Panisan, Roel T.
BSCHEM4
ARTICLE ANALYSIS:
Summary: The Applications of Gold Nanoparticles in the Diagnosis
and Treatment of Gastrointestinal Cancer
According to the World Health Organization's International Agency for Research on Cancer
(IARC"2020)'s Global Cancer Report," the top ten new cancer cases in China in 2020 are lung, colorectal,
gastric, breast, liver, esophageal, thyroid, pancreatic, prostate, and cervical cancers. Wherein, the majority
of instances are gastrointestinal malignancies, which are connected to people who eat a high-sugar, lowfiber diet, have helicobacter pylori infection, are sedentary, drink excessively, and smoke. And it is vital to
investigate the treatment and diagnosis of gastrointestinal malignancies in order to minimize the
incidence and mortality of gastrointestinal cancers, as well as enhance patient survival rates.
In fact, noble metal nanoparticles have gotten a lot of attention for the recent years. Because of
their remarkable efficacy and specificity in imaging, diagnosis, and therapy, they have gotten a lot of
interest in cancer medical research. Gold nanoparticles (GNPs) are one of them, and they're commonly
employed in cancer research because of their simplicity of synthesis, customizable size and shape,
exceptional biocompatibility, distinctive optical features, and surface plasmon resonance (SPR)
properties. Different GNPs have been created for various cancer kinds. Photothermal therapy,
immunotherapy, photodynamic therapy, gene therapy, targeted therapy, and a combination of several
treatments are all based on the expression of surface receptors and the tumor environment, allowing for
the integration of cancer diagnosis and treatment.
GNPs have various shapes, such as nanoclusters, nanorods, and nanocages and have been
reported in numerous investigations as shown in the Figure 1 below. Gold nanoparticles with a hollow
cage-like structure are known as gold nanocages. They have a large specific surface area, good surface
modifying characteristics, and a high drug loading rate when compared to the other two gold
nanoparticles. The PDL1 antibody was coupled with a TGF-b inhibitor and gold nanocages to create a
complex that can target colon cancer cells and accumulate in tumors. Also, by boosting the distal effect
mediated by synergistic immunotherapy, the complex inhibits colorectal cancer distant metastasis. Other
GNPs shape is the Gold nanorods which have two present wavelengths, which are the plasmon resonance
peaks, with short and long axis directions. In the gastric cancer cell, gold nanorods treated with lowdensity lipoprotein binding domain-binding polypeptide (RLT polypeptide) show a relatively obvious
inhibitory impact. Studies also shown that in comparison to the free medication doxorubicin, they showed
significant anti-tumor activity in the treatment of malignancies, as well as higher biosafety in vivo. Gold
nanoclusters are extremely small particles made up of dozens to tens of thousands of gold atoms and
when compared to gold nanorods and nanoclusters, a few hundred gold atoms exhibit exceptionally low
cytotoxicity and good red fluorescence properties, allowing them to efficiently avoid autofluorescence
background in vivo.
Figure 1. Different shape of GNPs.
The Roles of GNPs
GNPs have a passive tumor targeting effect and can passively accumulate at the tumor site due
to their small particle size. GNPs can also actively target the tumor site and impact tumor cells when paired
with particular active compounds as shown in Figure 2. The Chemotherapeutics and genes can be
delivered to the tumor location using gold nanoparticles, considerably increasing the potency of the active
chemical. It also has the ability to reprogram the tumor microenvironment and slow tumor progression.
Various gold nano delivery systems have been developed depending on the conditions of the tumor
microenvironment, such as acid and redox that release the active molecule in the tumor site to perform
an anti-tumor function. In addition, despite the fact that chemotherapy drugs have anti-tumor properties,
side effects such as high systemic toxicity in other organs of the body develop during the therapeutic
process. As a result, GNPs were used to deliver chemotherapy drugs to specific locations in order to
achieve precision therapy for gastrointestinal cancer.
Figure 2. Delivery using GNPs to regulate tumor cell
fate.
Applications of GNPs in Cancer Diagnosis and Cancer Therapy
Table 1. The important uses of GNPs in the diagnosis of gastrointestinal tumors.
Figure 3. Application of GNPs in cancer diagnosis.
The importance of GNPs in the diagnosis of gastrointestinal tumors is shown in Table 1. For
successful cancer treatment, precise diagnosis of tumor location and depth in patients is necessary. For
the clinical diagnosis and treatment of malignancies, imaging methods such as computed tomography (CT)
and nuclear magnetic resonance (MRI) are being used. The Ac-PEAuNPs were created with good
biocompatibility in mind. X-ray attenuation property that can accumulate in normal liver rather than
necrosis caused by HCC. It can be used as a negative CT imaging agent to provide a new technique of
diagnosing HCC. Also, due to its optimal tissue contrast resolution and multiplanarity, MRI is a noninvasive imaging technique that is chosen for soft tissue imaging. MRI and CT scans are commonly utilized
in cancer diagnosis, but their costs are considerable and the locations where they can be performed are
limited.
The PTX-PANP-FA complex was created by combining paclitaxel (PTX), gold nanorods,
perfluorohexane (PFH), and folic acid-bovine serum protein (FA-BSA). In a mouse model as shown in Figure
3 above, it can operate as an ultrasonic contrast agent, considerably improving photoacoustic contrast.
Furthermore, because of PFH vaporization, PTX-PANP-FA is rapidly degraded, resulting in rapid PTX
release after laser irradiation, changing the nanocarrier into a system with drug release, imaging, and
therapeutic properties. These studies showed that GNPs can be used as an imaging agent to aid in cancer
diagnosis. GNPs have an additional cancer therapeutic impact as compared to standard diagnostic
contrast agents.
Table 2 shows that in the therapy of gastrointestinal malignancies, GNPs play a critical role.
Photothermal therapy (PTT) is a one-of-a-kind cancer treatment that can heat tumor tissue selectively
while avoiding injury to surrounding tissues. Although a variety of nanoparticles are employed in PTT,
GNPs, in particular, can accumulate in tumor tissue passively. With photosensitizing medicines and laser
activation, photodynamic therapy (PDT) is a revolutionary approach for treating neoplastic disorders. As
a result, finding a novel cancer therapy that combines PTT with PDT for the treatment of gastrointestinal
cancer is an exciting prospect. Different cancer treatment techniques, such as PTT, PDT immunotherapy,
Table 2. The important uses of GNPs in the treatment and therapy of gastrointestinal tumors.
and chemotherapy, can be coupled to inhibit tumors due to the photothermal conversion effect and
surface modifiability of GNPs. The imaging capabilities of GNCs can also be used to integrate diagnosis
and treatment.
In fact, GNPs have several advantages in cancer therapy, including the ability to accumulate in
tumor cells and be easily metabolized by the body without harming other organs, the ability to be used
as active molecular vehicles to deliver drugs, miRNAs to tumor cells and tissues to improve the utilization
ratio and reduce toxicity to other parts of the body, and the ability to use photothermal conversion to
reduce toxicity to other parts of the body. It also serves as a diagnostic imaging agent for tumors.
Conclusion
In conclusion, GNPs can efficiently and precisely deliver cargos, particularly ncRNAs, that have
anti-cancer properties and can be employed to diagnose and treat gastrointestinal cancer. As a result,
GNPs have the potential to be used to image, diagnose, and treat gastrointestinal malignancies. However,
drug metabolism, safety concerns, in vivo efficacy, biocompatibility and stability, preparation costs, and
immunogenic problems all remain obstacles in the development process. Despite the difficulties that
clinical trials face, GNPs are still useful in the treatment and diagnosis of gastrointestinal cancer. GNPs in
biological systems have been the subject of substantial and fruitful investigation. The future clinical
application of imaging and cancer treatment is quite promising in terms of overcoming the difficulties
associated with the treatment and diagnosis of gastrointestinal cancer.