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GOLD
NANOPARTICLES FOR
CANCER TUMOR
TREATMENT
Master in Nanoscience 2010-2011
Departamento de Física de Materiales (UPV/EHU) y
el Centro de Física de Materiales (CSIC-UPV/EHU)
LOW DIMENSIONAL SYSTEMS AND NANOSTRUCTURES
Izaskun Leticia Combarro Palacios
Professor: Ángel Rubio
Gold nanoparticles for cancer tumor treatment
GOLD NANOPARTICLES FOR CANCER TUMOR TREATMENT
Nanoscience is an area that deals with the study of the materials of very small
dimensions. One of its principal achievements is to put to work on joint projects to
chemists, biochemists, doctors, physicists and other experts. Nowadays it is the base of
multitude of technological developments in many industrial areas as electronics,
communications, energy and medicine, where one of the most revolutionary methods it
is the manufacture of nanoparticles for medical applications.
Today, chemotherapy and radiotherapy are the most extended treatments against the
cancer, though it raises some disadvantages. The majority of the used medicaments are
designed to destroy the cells while they divide, especially those that do it to great speed,
as the tumor ones. These treatments consist in increasing the temperature of the tumor
cells (up to 45 °C) to destroy them, since the high temperatures can damage and
eliminate the carcinogenic cells and became cancer stem cells more sensitive to the
radiation.
The main problem it is the difficulty to take this heat directly to the carcinogenic cells,
since in the organism exist healthy cells that also multiply very rapidly and that are
affected by the treatment, generating side effects like nauseas and vomits, loss of
appetite, the fall of the hair… In the treatment with chemotherapy, 99 per cent of the
administered medicines do not reach to the tumor.
So, the key resides in finding small differences between healthy and tumor cells, that
allow to send selectively the medicament to the damaged area, where the treatment is
necessary. To try to settle this problem it has been studied the possibility of administrate
medicament towards certain type of tumors, to achieve that the treatment attacks to the
tumor ignoring to the rest of healthy cells by means of the employment of golden
nanoparticles.
The success in the treatment of the cancer depends on the early detection of the
malignant cells in the organism, so, the first step is to locate specific proteins that are in
the malignant cells. This is impeded by the current methods, since in the first stages of
the disease the concentration of the particles is very low and cannot be detected.
This revolutionary therapeutic method uses nanoparticles to detect the tumor position,
to supply there the required medicines, and later to destroy the diseased area.
It is a question of injecting nanocapsules of gold in the tumors. Ones the patient takes
the medicament, these nanocapsules cross the blood glasses reaching the tumors. When
they are illuminated with an external light, as a laser, they can help to fight against the
cancer, since they are used like nanosources of light and of heat.
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Gold nanoparticles for cancer tumor treatment
It is a physical phenomenon, a response of the metallic nanoparticles when a certain
light is send to them. When nanoparticles are illuminated, they generate a very intense
field of light in their surface, so when they hold to a specific zone, this zone shines, so
the tumor is detected as it is illuminated by nanoparticles (see figure bellow).
Cancer tumor coated with gold
nanoparticles
Healthy tissue
Figure 1: Illuminated gold particles for tumor position detection.
On the other hand, the warming of the nanoparticles takes place as they are activated by
the laser. Golden nanoparticles allow turning efficiently the light that is send to them in
heat. They absorb certain color of the light, so if we deliver them the suitable color, the
particles warm up, and their temperature increases five degrees, sufficient to burn the
carcinogenic cells.
This treatment is very effective in the therapy against the cancer on having introduced
the nanoparticles in a selective form only in the tumor sick cells, and not in the healthy
ones.
Figure 2: Golden nanoparticles attacking to the tumor.
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Gold nanoparticles for cancer tumor treatment
In order to make this possible, these nanoparticles of gold must have some agents as
agents of addressing and permeabilizing agents that allow to direct the medicament to
the tumor in a selective way and to introduce it inside the damaged cell.
The principal aim is to design and to fabricate nanoparticles that can be illuminated in
the presence of very low concentrations of carcinogenic cells, that is, in the first stages
of the disease. The idea is to detect very reduced concentrations of certain damage
molecules in a blood sample of a patient. This allows detecting a cancer in a level of
very early development, which facilitates its treatment.
Another principal problem in the fight against the cancer is a small population of tumor
stem cells that resist to the radiation and to the chemotherapy treatments, as these few
cells can produce the recurrence of the disease after the treatment.
To solve this problem, Scientifics are working to try to join the nanoparticles with fibers
of ribonucleic acid (siRNA) capable of silencing certain genes. This way, when
introducing the nanoparticle joined a certain siRNA inside the tumor cell, the objective
is to inhibit the proliferation and the survival of the tumor cells, stopping its growth.
Summarizing, the idea is that the doctors administer to the patients million of
nanoparticles of gold programmed to find and to stick to the carcinogenic tumors. Once
the nanoparticles locate the tumor, the doctors would use X-rays to see it. The doctors
radiate nanoparticles with a light source (infrared light) with the aim to detect the light
that the nanoparticles issue, detect their location, and localize the region of the organism
that is damaged.
But these particles also transport a very powerful chemotherapy treatment to the cells of
the tumor, since they produce heat, eliminating the tumor cells, without damaging the
healthy ones, reducing in this way the side effects and preventing the disease from being
regenerated.
The results of this technology demonstrate a minor rate of carcinogenic cells in
proliferation, fewer tumors are formed, which suggests that the treatment blocks the
cancer stem cells growth and makes them much more sensitive to the radiation.
The gold has turned out to be the ideal material since its degree of toxicity is minor than
other materials. In addition, these particles can be easily directed to the tumor and turn
efficiently the light that is send to them in heat.
One of the principal advantages of this technology is that it is possible to detect the sick
proteins in very low concentrations, which allows detecting the cancer in early
conditions. For example, with conventional processes it is possible to detect a gram of
protein, at the time that this method is capable of detecting a milligram.
In addition, gold nanoparticles can reveal so small carcinogenic tumors that are
impossible to be detected with the systems and technologies used nowadays. So
manipulating the nanoparticles in order that they have aptitude to transport medicines to
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Gold nanoparticles for cancer tumor treatment
the tumor, a 10 times more effective (compared with the conventional ones,
chemotherapy and radiotherapy) treatment can be achieved and without side effects.
On the other hand, nanoparticles are more precise than the scalpel of a surgeon, so, this
technology might eliminate the cells to which the surgeon cannot reach, preventing the
disease being generated.
The major difficulty of this technology is to find a substance capable of encasing the
medicines and preventing them from decomposing in the organism and affecting the
health of the patient. It is a question of wrapping the nanoparticles in some substance
that the body could reject them.
In addition, the difficulty of bringing these revolutionary concepts to human clinic
causes that many projects do not see the light and remain as scientific progresses
without patients being able to benefit from them.
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