1. NANOTECHNOLOGY AND CANCER- A REVIEW
R.M.Nehru & Om Pal Singh
Information and Technical Services Division
AERB
2. What is Nanotechnology?
•The prefix Nano comes from the word nanometer (nm) which is the term
for one billionth of a meter.
•In its broadest usage, the term nanotechnology covers making
structures in the range of 1 nm to 100 nm.
• one nanometer in length is only about five atoms long.
•Nanotechnology, in its traditional sense, means building things from the
bottom up, with atomic precision. This theoretical capability was
envisioned as early as 1959 by the renowned physicist
Richard Feynman.
Fig:1 With 15,342 atoms, this parallel-shaft
speed reducer gear is one of the largest
nanomechanical devices ever modeled in
atomic detail.
3. General-Purpose Technology
Nanotechnology is often referred to as a general-purpose technology.
That's because in its advanced form it will have significant impact on
almost all industries and all areas of society.
It offers better built, longer lasting, cleaner, safer, and smarter products for
the home, for communications, for medicine, for transportation, for
agriculture, and for industry in general.
Imagine a medical device that travels through the human body to seek out
and destroy small clusters of cancerous cells before they can spread.
Or a box no larger than a sugar cube that contains the entire contents of
the Library of Congress.
Or materials much lighter than steel that possess ten times as much
strength. — U.S. National Science Foundation
4. Nanotechnology in cancer detection and diagnosis
Detection of cancer at an early stage is a critical step in improving
cancer treatment.
Currently, detection and diagnosis of cancer usually depend on changes
in cells and tissues that are detected by a doctor's physical exam or
imaging expertise.
Instead, scientists would like to make it possible to detect cancer when
the earliest molecular changes are present, long before a physical exam
or imaging technology is effective. To do this, they need a new set of
tools.
Source:National Cancer Institute website
5. Nanotechnology is uniquely promising as an early
detection tool for several reasons:
To successfully detect cancer at its earliest stages, scientists must be able
to detect molecular changes even when they occur only in a small
percentage of cells. This means the necessary tools must be extremely
sensitive. The potential for nanostructures to enter and analyze single cells
suggests they could meet this need.
Many nanotechnology tools will make it possible for clinicians to run tests
without physically altering the cells or tissue they take from a patient. This is
important because the samples clinicians use to screen for cancer are often
in limited supply. Scientists would like to perform tests without altering cells,
so they can be used again if further tests are needed.
Reductions in the size of tools means that many tests can be run on a single
small device. This will make screening faster and more cost-efficient.
Source:National Cancer Institute website
6. How can nanotechnology be used in cancer treatment?
•Nanotechnology may also be useful for developing ways to eradicate
cancer cells without harming healthy, neighboring cells.
•Scientists hope to use nanotechnology to create therapeutic agents that
target specific cells and deliver the toxin in a controlled, time-release
manner. Researchers aim eventually to create single agents that are able to
both detect cancer and deliver treatment.
•The ultimate goal of this research is nanoparticles that will circulate
through the body, detect cancer-associated molecular changes, assist with
imaging, release a therapeutic agent, and then monitor the effectiveness of
the intervention.
Source:National Cancer Institute website
7. Tools for Nanotechnology
Cantilevers
•Nanoscale cantilevers - tiny bars anchored at one end - can be
engineered to bind to molecules associated with cancer. They may bind to
altered DNA sequences or proteins that are present in certain types of
cancer. When the cancer-associated molecules bind to the cantilevers,
changes in surface tension cause the cantilevers to bend.
•By monitoring whether or not the cantilevers are bent, scientists can tell
whether the cancer molecules are present. Scientists hope this bending will
be evident even when the altered molecules are present in very low
concentrations. This will be useful in detecting early molecular events in
the development of cancer.
DNA side and Top View
Source:National Cancer Institute website
8. Nanopores
•To read genetic code on single strands of DNA to detect errors that may
contribute to cancer, Scientists believe nanopores, tiny holes that allow
DNA to pass through one strand at a time, will make DNA sequencing
more efficient.
•As DNA passes through a nanopore, scientists can monitor the shape
and electrical properties of each base on the strand. Because these
properties are unique for each of the four bases that make up the genetic
code, scientists can use the passage of DNA through a nanopore to
decipher the encoded information, including errors in the code known to
be associated with cancer.
Source:National Cancer Institute website
9. Nanotubes
•Even smaller than nanopores are nanotubes. Nanotubes, carbon rods
about half the diameter of a molecule of DNA, will also help identify DNA
changes associated with cancer.
•It also help researchers to pinpoint the exact location of those changes.
•Mutated regions associated with cancer are first tagged with bulky
molecules. Using a nanotube tip resembling the needle on a record player,
researchers can then trace the physical shape of DNA.
•A computer translates this information into a topographical map. The
bulky molecules identify the regions on the map where mutations are
present. Since the location of mutations can influence the effects they
have on a cell, these techniques will be important in predicting disease.
Source:National Cancer Institute website
10. Quantum dots
•Innovative tool that will allow scientists to detect critical changes in DNA in
the body is quantum dots.
•Quantum dots are tiny crystals that glow when they are stimulated by
ultraviolet light. The wavelength, or color, of the light depends on the size of
the crystal.
•Latex beads filled with these crystals can be designed to bind to specific DNA
sequences. When the crystals are stimulated by light, the colors they emit act
as dyes that light up the sequences of interest.
•By combining different sized quantum dots within a single bead, scientists
can create probes that release a distinct spectrum of various colors and
intensities of lights, serving as a sort of spectral bar code.
Source:National Cancer Institute website
11. Nanoshells
•Nanoshells, another recent invention, are miniscule beads coated with
gold. By manipulating the thickness of the layers making up the nanoshells,
scientists can design these beads to absorb specific wavelengths of light.
•The most useful nanoshells are those that absorb near-infrared light, which
can easily penetrate several centimeters of human tissue. The absorption of
light by the nanoshells creates an intense heat that is lethal to cells.
•Researchers can already link nanoshells to antibodies that recognize
cancer cells. Scientists envision letting these nanoshells seek out their
cancerous targets, then applying near-infrared light.
•In laboratory cultures, the heat generated by the light-absorbing nanoshells
has successfully killed tumor cells while leaving neighboring cells intact.
Source:National Cancer Institute website
12. Challenges associated with nanotechnology
•Today, much of the science on the nanoscale is basic research, designed
to reach a better understanding of how matter behaves on this small scale.
Matter behaves differently on the nanoscale than it does at larger levels.
•The factors that govern larger systems do not necessarily apply on the
nanoscale. Because nanomaterials have large surface areas relative to
their volumes, phenomena like friction and sticking are more important
than they are in larger systems. These factors will affect use both inside
and outside the body.
•Other challenges apply specifically to the use of nanostructures within
biological systems. Nanostructures can be so small that the body may
clear them too rapidly for them to be effective in detection or imaging.
Larger nanoparticles may accumulate in vital organs, creating a toxicity
problem.
Source:National Cancer Institute website
13. How are nanodevices created?
There are two basic approaches for creating nanodevices. Scientists refer
to these methods as the top-down approach and the bottom-up
approach. The top-down approach involves molding or etching materials
into smaller components. This approach has traditionally been used in
making parts for computers and electronics.
The bottom-up approach involves assembling structures atom-by-atom
or molecule-by-molecule and may prove useful in manufacturing devices
used in medicine
Source:National Cancer Institute website
14. What are the advantages of applying nanotechnology
to biological systems?
•Most animal cells are 10,000 to 20,000 nanometers in diameter. This
means that nanoscale devices (having at least one dimension less than
100 nanometers) can enter cells and the organelles inside them to interact
with DNA and proteins.
•Miniaturization will allow the tools for many different tests to be situated
together on the same small device.
•This means that nanotechnology could make it possible to run many
diagnostic tests simultaneously as well as with more sensitivity.
Source:National Cancer Institute website
15. What nanotechnology tools are being developed for
cancer treatment?
Research is being done on a number of nanoparticles that will facilitate drug
delivery. One such molecule with potential to link treatment with detection
and diagnosis is known as a dendrimer. A useful feature of dendrimers is
their branching shape, which gives them vast amounts of surface area to
which scientists can attach therapeutic agents or other biologically active
molecules. A single dendrimer can carry a molecule that recognizes cancer
cells, a therapeutic agent to kill those cells, and a molecule that recognizes
the signals of cell death. Researchers hope to manipulate dendrimers to
release their contents only in the presence of certain trigger molecules
associated with cancer. Following drug release, the dendrimers may also
report back whether they are successfully killing their targets.
Source:National Cancer Institute website
16. How soon will nanotechnologies be used in patient
care?
•These technologies are in various stages of discovery and development.
Experts believe that quantum dots, nanopores and other devices for
detection and diagnosis may be available for clinical use in five to 15
years.
•Therapeutic agents are expected to be available within a similar time
frame. Devices that integrate detection and therapy could be used clinically
in about 15 or 20 years.
Source:National Cancer Institute website
28. “ This lecture is dedicated to National Cancer Institute as we
have gained much information on Nanotechnology from its
resources and other links associated to it”.
