Cancer-Battling 'Nanoshells'
Presented By:
Muhammad Zain Akram (NT-1007)
Why Nanotechnology ?
• Conventional chemotherapy employs
drugs that are known to kill cancer cells
effectively. But these cytotoxic drugs kill
healthy cells in addition to tumor cells,
leading to adverse side effects such as
nausea, neuropathy, hair-loss, fatigue, and
compromised immune function
Why Nanotechnology ?
• Nanoparticles can be used as drug
carriers for chemotherapeutics to deliver
medication directly to the tumor while
sparing healthy tissue. Nanocarriers have
several advantages over conventional
chemotherapy
Advantages of Nanocarriers over
conventional chemotherapy
• Nanocarriers have several advantages over
conventional chemotherapy. They can:
– protect drugs from being degraded in the body before they reach
their target.
– enhance the absorption of drugs into tumors and into the
cancerous cells themselves.
– allow for better control over the timing and distribution of drugs to
the tissue, making it easier for oncologists to assess how well they
work.
– prevent drugs from interacting with normal cells, thus avoiding
side effects.
Fighting Cancer With
Nanoshells
• Moving away from conventional chemotherapeutic
agents that activate normal molecular mechanisms
to induce cell death, researchers are exploring ways
to physically destroy cancerous cells
• One such technology “Nanoshells” is being used in
the laboratory to thermally destroy tumors .
Fighting Cancer With
Nanoshells
• Nanoshells can be designed to absorb light of different
frequencies, generating heat (hyperthermia). Once the cancer
cells take up the nanoshells (via active targeting), scientists
apply near-infrared light that is absorbed by the nanoshells,
creating an intense heat inside the tumor that selectively kills
tumor cells without disturbing neighboring healthy cells.
• Similarly, new targeted magnetic nanoparticles are in
development that will both be visible through Magnetic
Resonance Imaging (MRI) and can also destroy cells by
hyperthermia.
What are Nanoshells??
• Metal nanoshells are a novel type of composite spherical
nanoparticle consisting of a dielectric core covered by a thin metallic
shell which is typically gold.
• Nanoshells possess highly favorable optical and chemical properties
for biomedical imaging and therapeutic applications.
• By varying the relative the dimensions of the core and the shell, the
optical resonance of these nanoparticles can be precisely and
systematically varied over a broad region ranging from the near-UV
to the mid-infrared.
Significance of Nanoshells
• Nanoshells have a core of silica and a metallic outer layer. These
nanoshells can be injected safely, as demonstrated in animal
models.
• Metal nanoshells are a class of nanoparticles with tunable optical
resonances.
• Nanoshells should work in most soft tissue tumors but would be
most effective on cancers that can't be removed surgically because
they're in an awkward location, such as in the brain.
• recent study shows that you can inject nanoshells intravenously and
they will accumulate in tumor sites because the blood vessels in
tumors are leakier than elsewhere in the body.
Cancer Battling Gold Nanoshells
• Gold nanoshells are spherical particles with diameters typically
ranging in size from 10 to 200 nm .
• They are composed of a dielectric core covered by a thin gold shell.
• As novel nanostructures, they possess a remarkable set of optical,
chemical and physical properties, which make them ideal
candidates for enhancing cancer detection, cancer treatment,
cellular imaging and medical biosensing.
• Gold nanoshells are unique in that they combine many ideal
features in a single particle.
• Nanoshells can be engineered to target cancerous cells and at the
same time designed to interact with specific wavelengths of light.
Depending upon the wavelength of incident light, nanoshells can
either scatter or absorb light, creating applications as both a cancer
imaging agent or therapeutic one.
• They can be tuned to preferentially absorb or scatter
light at specific wavelengths in the visible and near infrared ( NIR ) regions of the spectrum.
• In the NIR ‘ tissue window ’ , light penetration into tissue
• is optimal.
• Nanoshells tuned to absorb NIR radiation are particularly
useful as mediators of photothermal cancer therapy
because they efficiently convert absorbed radiation into
heat, and are thermally stable at therapeutic
temperatures.
• Furthermore, nanoshells preferentially accumulate at
tumor sites due to their nanoscale dimensions.
Gold Nanoshells
Called nanoshells, the golden balls have a bit of mica in their center
and can be designed to absorb radiation at various frequencies
What's special about gold nanoshell?
• Nanoshells can come in many shapes and sizes, but all are
composed of a core and a shell. The core is the interior part and the
shell is the material coated around the core. In the case of a gold
nanoshell the core is a ball of silica and the shell is a thin layer of
gold. Gold nanoshells have similar properties to gold nanoparticles ,
but have the added benefit of being tunable to different wavelengths
of light. The human body only allows certain wavelengths of light to
pass through the body; these wavelengths are outside the visible
spectrum (colors we can see) and are near-infrared light. Gold
nanoshells are tuned to these wavelengths of light so that they can
trigger properties of nanoshells without opening the body
What's special about
Gold nanoshell?
• The optical response of gold nanoshells depends dramatically on
the relative size of the nanoparticle core and the thickness of the
gold shell.
• By varying the relative core and shell thicknesses, the color of
• Gold nanoshells can be varied across a broad range of the optical
spectrum that spans the visible and the near infrared spectral
regions .
• Gold nanoshells can be made to either preferentially absorb or
scatter light by varying the size of the particle relative to the
wavelength of the light at their optical resonance.
Synthetic protocol for the fabrication of
Gold Nanoshells
• Grow or obtain silica nanoparticles dispersed in Solution.
• Attach very small (1-2 nm) metal “seed” colloid to the
surface of the nanoparticles via molecular linkages;
these seed colloids cover the dielectric nanoparticle
surfaces with a discontinuous metal colloid layer.
• Grow additional metal onto the “seed” metal colloid
adsorbates via chemical reduction in solution.
Battle Against Cancer
• Gold nanoshells that are designed to absorb radiation at
various frequencies, absorb certain types of radiation
becoming a new weapon in the ongoing battle against
cancer.
• Once the nanoshells are attached to the cancer cells,
only laser light is needed to treat the cancer. Near
infrared (NIR) light passes through the body and reaches
the gold nanoshell.
• The tuned gold nanoshells receives the NIR light and
convert the light energy into heat, killing the cancer cells
• Near infrared light is a type of low-energy radiation not absorbed by
living tissues. However, the nanoshells can be designed to absorb this
light, which heats them up.
• Nanoshells use surface plasmon resonance, or a wave-like excitation of
electrons along the surface, to convert laser light into heat. Because
nanoshells are metallic on the outside and small in size, the laser light
interacts with the shell, causing surface plasmon resonance.
• Electrons in the gold prefer to have low energy, so they give off any
extra energy as heat to the surrounding environment, including the
attached cancer cell.
• The Texas researchers first experimented with cultured human breast
cancer cells in a solution containing nanoshells and then turned to
tumors in mice.
In both cases, temperatures inside the tumors reached levels high
enough to damage cells within 4 to 6 minutes, killing the tumors but
leaving surrounding tissue unharmed.
Battle Against Cancer
• This process causes the temperature of the cancer cell
to increase 20°C to 35°C or 68°F to 95°F after 4-6
minutes of laser light exposure, causing the cell to
almost double in temperature! Nanoshells convert light to
heat well enough that they can be used to heat up a
space 1000 times larger than their size. The transferred
heat is strong enough to destroy the cancer cell. Healthy
cells then consume the dead cancer cells through
phagocytosis. When the process is done, only healthy
cells remain and there are no traces of cancer.
Benefits of nanoshell treatment
over standard treatments
• The use of nanoshells to treat cancer has benefits over
standard treatments today. Standard treatments such as
chemotherapy, radiation therapy, and surgery are used
to destroy cancers cells. These treatments destroy
cancer cells, but also many healthy cells in the process
• Due to their small size, nanoshells have the ability to
only heat up the attached cancer cell. This allows them
to target and destroy cancer cells while minimizing the
amount of damage done to healthy cells.
Benefits of nanoshell treatment
over standard treatments
• Nanoshells also provide a less intrusive treatment option
than traditional methods.
• Once the nanoshells are injected into the blood stream
and attach to the cancer cells, they are triggered from
outside the body without any cutting or harmful radiation.
The NIR light can pass harmlessly through most of the
body and only interact with the nanoshells, causing them
to heat up and destroy the cells they have attached to.