An Overview of Nanotechnology Prof. Dr. Moustafa M. Mohamed Biophysics Department Medical Research Institute Alexandria University

Background and Definition of Nanotechnology On Dec. 29, 1959, at the California Institute of Technology, Nobel Laureate Richard P. Feynman gave a talk at the annual meeting of the American Physical Society. He talked about: problem of manipulating and controlling things on a small scale. building nanoobjects atom by atom or molecule by molecule. In 1998 : White House created the “Interagency Working Group on Nanoscience, Engineering and Technology (IWGN)”. In a January 2000 : President William J. Clinton talked about the exciting promise of nanotechnology. Later that month: An ambitious $ 497 million federal, multi-agency National Nanotechnology Initiative (NNI) in 2001: made it a top science and technology priority .

UNDERSTANDING NANOSCIENCE Feynman (1959) hypothesized that atoms and molecules could be manipulated like building blocks 1989 when scientists at IBM manipulated 35 xenon atoms to form the letters IBM

Two basic approaches for creating nanodevices: Top-down approach:- involves molding or etching materials into smaller components. used in making parts for computers and electronics. Bottom-up approach:- involves assembling structures atom- by-atom or molecule-by-molecule (useful in manufacturing devices used in medicine).

Nanotechnology is defined as study and use of structures between 1 nanometer and 100 nanometers in size,  building machines at the molecular scale, and manipulation of materials on an atomic scale

Nanometer A nanometer is a billionth of a meter: It is only 1/80,000 the width of a human hair. Ten hydrogen atoms could be laid side-by- side in a single nanometer Diameter of a human hair ~ 80,000nm

Nanotechnology Includes Nanomaterials Nanowires Nanomembranes Nanoparticles Nano-others

Multidisciplinary Nanotechnology involves scientists from many different disciplines Physics Chemistry Biology NANOTECHNOLOGY Mathematics Engineering

How matter behaves on Nano-scale large surface areas Relative to their volumes and weight friction and sticking are more important More reactive to some other molecules Have different optical properties

Nanomaterials Have More Atoms on the Surface Materials of the micro (1x10-6m) and especially nano (1x10-9m) size have more atom exposed on the outside then inside Volume = 18x19x1 nm3 or 15x8x16 atoms = 1920 atoms total 976 or 51% of the atoms are at the surface Nanomaterial Volume = 3x3x0.7 mm3 or ~4 million atoms total 976 or 4% of the atoms are at the surface Micro-scaled Material A 1x1x1 cm3 cube will have 0.00072% of the atoms exposed to the surface

Surface Atoms Interact more with the Environment Light Temperature Heat Cold Sound The forms of energy that affect us in the environment can affect molecules. Energy comes from the environment to affect molecular nature. Since more molecules are on the surface, the affect is more pronounced.

Gold appears with different color depending upon the particle size Optical properties Gold appears with different color depending upon the particle size purple red, or greenish Titanium dioxide and zinc oxide Both appear white at macro scale and translucent at nanoscale

. Influence the mechanical properties Improve performance Adding nano-sized components to conventional materials Improve performance Influence the mechanical properties - Carbon nanotube exhibit tensile strengths 100 times that of steel. - either metallic or semiconducting depending on their configuration. Novel materials ( lightweight replacements for metals) .

Nanotechnology Applications nanotechnology plays a role in chemical industry Increasing the efficiency of energy production Reduction of energy consumption Use of more environmentally friendly energy systems Novel semiconductor devices Heavy Industry

Lighter and stronger materials will be of immense use to aircraft manufacturers lighter and stronger materials will be useful for creating vehicles that are both faster and safer Nanotechnology can be applied in the production, processing, safety and packaging of food.

Consumer goods Cosmetics. food. Nanoceramic particles. clothes.

Nanomedicine Overview What if doctors could search out and destroy the very first cancer cells? What if a broken part of a cell could be removed and replaced with a miniature biological machine? What if pumps molecular size could be implanted to deliver life-saving medicines precisely when and where they are needed?

Detect minute amounts of Nano-Medicine current state of the art: Detect 109 cancer cells. What if… Detect minute amounts of cancer cells. foreign material.

Medicine What if… Target only the disease. Administer a small dosage directly to the disease.

Nanomedicine Nanomedicine is the medical use of nano-sized particles to: deliver drugs, heat, light or other substances to specific cells in the human body. detection and/or treatment of diseases or injuries within the targeted cells, thereby minimizing the damage to healthy cells in the body.

Nanotechnology in Medicine: Current Applications While most applications of nanotechnology in medicine are still under development Nanocrystalline silver is already being used as a antimicrobial agent in the treatment of wounds.

Nanotechnology in Medicine: Applications under Development Qdots Tiny crystal particles glow when they are stimulated by ultraviolet and used to detect cancer and identify the location of cancer cells in the body. Nanoparticles attach to cells infected with various diseases and allow a lab to identify. deliver chemotherapy drugs directly to cancer cells to minimize damage to healthy cells. Nanoshells that concentrate the heat from infrared light to destroy cancer cells with minimal damage to surrounding healthy cells.  Nanotubes used in broken bones to provide a structure for new bone material to grow.

Nanoparticles used in medicine as: contrast agents for medical imaging therapeutics for treating cancer in vivo and in vitro biomedical research and applications. diagnostic devices, analytical tools, physical therapy applications, and drug delivery vehicles.

Body may clear them too rapidly for them to be effective in detection or imaging may accumulate in vital organs, creating a toxicity problem

Most animal cells are 10,000 to 20,000 nm in diameter so nanoscale devices can enter cells and to interact with DNA and proteins detect disease in a very small amount of cells or tissue. monitor cells within a living body.

Nanodevices Can Improve Cancer detection and imaging

In order to successfully detect cancer at its earliest stages:- scientists must be able to detect molecular changes in a small percentage of cells. tools must be extremely sensitive. nanostructures to enter cells and meet this need.

Researchers hope that nanotechnology will Miniaturization will Researchers hope that nanotechnology will allow them to run many diagnostic tests simultaneously. allow the tools for many different tests to be situated together on the same small device. make it possible for clinicians to perform tests without altering cells, so the cells can be used again. improving methods of reading the genetic code

Nanotubes carbon rods about half the diameter of a molecule of DNA help to identify DNA changes associated with cancer. can detect the presence of altered genes pinpoint the exact location of those changes. seek out specific mutations in the DNA and bind to them. Trace physical shape of DNA Pinpoint mutated region Creates a map showing DNA molecules, including the tags identifying important mutations These techniques will be important in predicting disease.

Quantum dots Tiny crystal particles glow when they are stimulated by ultraviolet and used to detect cancer, The wavelength or color of the emitted light depends on the size of the crystal Scientists can design quantum dots that bind to sequences of DNA that are associated with the disease. When the quantum dots are stimulated with light, they emit their unique bar codes, or labels, making the critical, cancer-associated DNA sequences visible. Another advantage of quantum dots is that they can be used in the body, eliminating the need for biopsy.

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 their toxin in a controlled, time-released manner.

Nanoshells Nano-beads coated with gold. By manipulating the thickness scientists can design these beads to absorb specific wavelengths of light. The most useful nanoshells are those that absorb near-infrared light . 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. the heat generated by the light-absorbing nanoshells has successfully killed tumor cells while leaving neighboring cells intact.

Researchers aim to create a single nanodevices that do much more than deliver treatment. assist in imaging inside the body, recognize precancerous or cancerous cells, release a drug that targets only those cells, and report back on the effectiveness of the treatment.

Dendrimer One molecule with potential to link treatment with detection and diagnosis is known as a dendrimer. Dendrimers are man-made molecules about the size of an average protein, and have a branching shape. This shape 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 target

Experts believe that:- quantum dots, nanopores, and other devices for detection and diagnosis may be available for clinical use in 5 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.

Laser-Guided Smart Nano-Bombs for Brain Tumors Drug delivery system that involves: Drug-toting nanoparticles and Guiding peptide to target cancerous cells in the brain. Via this method more of the drug can be delivered to a tumor's general vicinity.

Photodynamic Therapy (Photofrin) Photofrin is used in the treatment of esophageal, bladder and skin cancers Photodynamic activated by a laser after it has entered the bloodstream. patients must remain out of bright sunlight and even unshaded lamps for up to 30 days after receiving treatment. 40-nanometer-wide particles carry the drug, avoid much of the photosensitivity,

Magneto-nano-particles The researchers also hope someday to: use nanoparticles magnetic properties to concentrate anti-cancer drugs. external magnets fields would be focused where the cancer is located. That would reduce the side effects from chemotherapy.

Insulin Nanopump Nanopump provides better control of the administered insulin doses. able to control delivery at the nanoliter level. prevents over-dosing and detects under-delivery, occlusion, air bubbles and other potential malfunctions. can be worn as a nearly invisible patch on the skin. The small size frees the patient from concerns

Filtration Nanoporous membranes are suitable for a mechanical filtration with extremely small pores smaller than 10 nm (“nanofiltration”) and may be composed of nanotubes. One important field of application for ultrafiltration is medical purposes as can be found in renal dialysis. Magnetic nanoparticles offer an effective and reliable method to remove heavy metal contaminants from waste water by making use of magnetic separation techniques.

Does Nanotechnology Represent a Danger to Society? Little known about the toxicology and biological effects of nanotechnology. There are uncertainties with:- potential routes of exposure, movement of nanomaterials once they enter the body and the body’s response to nanomaterials Different particle characteristics such as surface area, solubility, shape and surface chemistry influence the toxicity of the particle

small size nanoparticles move past the protective mechanisms of the body. Exposure to nanomaterials is most likely to occur through inhalation, but may also occur through the skin or by ingestion Nanoparticles may cause lung as cancers, inflammation, fibrosis and breathing difficulties Some nanoparticles are able to move from the lungs into the blood stream and be distributed into other organ Nanoparticles could cross the blood-brain barrier.