Presentation on theme: " INTRODUCTION Definition of Nanomaterials Types of Nanomaterials Properties of Nanomaterials Why Nanotechnology in the Medical Field."— Presentation transcript:
Nanomaterials are commonly defined as materials with an average grain size less than 100 nanometers.
For nano-scale grains, most of the atoms will be on the surface of the grain. The very building blocks of matter – optical, mechanical, electronic, and magnetic behavior – can change dramatically.
Diseases are caused largely by damage at the molecular and cellular level. Today's surgical tools are, at this scale, large and crude. From the viewpoint of a cell, even a fine scalpel is a blunt instrument more suited to tear and injure than heal and cure. Modern surgery works only because cells have a remarkable ability to regroup, bury their dead and heal over the injury.
“The manufacturing technology of the 21st century," should let us economically build a broad range of complex molecular machines. It will let us build fleets of computer controlled molecular tools much smaller than a human cell and built with the accuracy and precision of drug molecules. Such tools will let medicine, for the first time, intervene in a sophisticated and controlled way at the cellular and molecular level. They could remove obstructions in the circulatory system, kill cancer cells, or take over the function of subcellular organelles. Just as today we have the artifical heart, so in the future we could have the artificial mitochondrion.
Conventional artificial joints are made of titanium to which osteoblasts adhere to upon implant. Conventional titanium have surface features on the scale of microns Causing the body to recognize them as foreign materials Prompting a rejection response. Any tiny rejection response can Weaken the implant attachment Become loose and painful Human Osteoblasts Titanium Joints
At Rice University, researchers found that osteoblasts would adhere much better to materials that possess surface bumps about as wide as 100 nanometers which mimic surface features of proteins and natural tissues prompting cells to stick better and promoting the growth of new cells. Therefore, osteoblasts attach better to titanium coated with nanotubes. Having the same chemistry as DNA makes it easy for other body protein components to attach to the surface of these nanotubes. Preventing rejection response SEM of SWNT.
The self-assembling nanotubes are made of guanine and cytosine, which are called “base pairs” molecules that come together to form DNA. They are programmed to link in groups of six to form rosette-shaped rings. Numerous rings then combine together to form the rod-like nanotubes with the width of only about 3.5 nanometers. Self-assembly of rosette-shaped rings of nanotubes.
EXPERIMENT: Titanium was coated with these nanotubes and placed in Petri dishes containing a liquid of suspension of bone cells colored with a fluorescent dye. After a few hours, the coated titanium was washed and looked at under the microscope to count the number of osteoblasts attached to it. It was found that out of 2,500 cells; about 2,300 to 2,400 cells adhered to the coated titanium. That compares with about 1,500 cells adhering to titanium not coated with the nanotubes, representing an increase of about one-third. Moreover, an improved osteoblasts function was observed in the coated titanium compared to that not coated.
At the University of Illinois, researchers coated carbon nanotubes with an enzyme that makes hydrogen peroxide in the presence of sugar. Hydrogen peroxide, in turn, triggers electrons into the nanotubes. Upon exposure to infrared light, these electron-coated nanotubes will glow which is a reaction unique to nanotubes. CNT attaching to other molecules
These nanotubes can easily be packed in a hair-like capsule the size of splinter. This capsule can be painlessly implanted under the skin. Infrared light is then shined at the place of the implant. A small handheld device is used to measure the intensity of the glow which is directly related to the amount of sugar in the blood. Scientists at the University of Illinois were able to get continuous readings of a number of medically important measures, such as cholesterol or hormone levels, without having to get a drop of blood from the patient.
Quantum dots are defined as “devices that contain a tiny droplet of free electrons and that their size and shape and therefore the number of electrons they contain, can be precisely changed.” Upon exposure to ultraviolet light, quantum dots glow with different hue that varies according to the size of the dot. a 2-nanometer diameter glow bright green a 5-nanometer diameter glow brilliant red This nanodevice has already been used as a research tool to help understand how different biological materials such as proteins and DNA choose their transportation paths within the body. Quantum dots are droplets of free electrons.
Quantum dots are coated with different materials that will adhere to the surface of the materials of interest. The coated dots will then be injected to the cells grown in the Petri dishes. The dots will adhere to the materials of interest and upon exposure to ultraviolet light the dots with attached materials will glow. By injecting different sizes of quantum dots, different colors will be given off. Quantum dots shine brighter and longer than conventional dyes. Scientists are currently trying to use quantum dots to diagnose diseases in early stages. When exposed to ultraviolet light, quantum dots glow with different hue that varies according to its size.
Therasphere is a therapeutic device that delivers radiation directly to the tumor cells in the liver using glass microsphere. – –The size of a microsphere is 20-30 µm in diameter One-third the size of a human hair. It has currently been used in the U.S., Canada and Australia. Comparison of a human hair with Therasphere.
It consists of microspheres of 17Y 2 O 3 -19Al 2 O 3 -64SiO 2 (mole %) glass. Prepared by conventional glass melting technique. 89 Yttrium in this glass is non-radioactive. – –Activated by neutron bombardment to 90 yttrium which is a β-emitter with half life of 64.1 hours (2.68 day s). Millions of these beads can be injected into the bloodstream, and then guided via a catheter into the hepatic artery, the liver’s main blood vessel.
When they arrive in the liver, the radiation-laden spheres get stuck within the smaller blood cells that sustain tumors, rather than the larger vessels feeding healthy tissue. – –These spheres produce radiation only to tissue with an average range of 2.5 mm and maximum range of less than 1 cm. The Beta energy is then able to attack the tumor with minimal residual damage to the liver. – –The 90 yttrium then decays to stable 90 zirconium.
Cancerous cells are poorly supplied with oxygen to produce lactic acid. – –Therefore, these cells can be destroyed around 43 o C. – –By contrast, normal cells can be kept alive even around 48 o C. Because the tumor tissue has higher heat sensitivity and smaller cooling effect due to blood flow, the temperature in the tumor tissue easily rises compared to healthy tissue.
Kokubo and co-workers prepared a ferromagnetic glass-ceramic containing 36 weight % of magnetite (Fe 3 O 4 ) in a CaO-SiO 2 matrix. These materials are injected to the cancerous cells in the form of microsphere in the size of 20 – 30 µm in diameter through the blood vessels in the same manner as the radioactive microspheres. Upon exposure to alternating magnetic field, these ferri- or ferromagnetic particles radiates off heat by magnetic hysteresis loss which in turn rises the temperature of the cancerous cells causing it to die. After injection of ferri-/ferromagnetic particles, it is exposed to alternating magnetic field.
Success Rate of Hyperthermia vs Chemo-therapy: (Statistics based on 22 clinical articles, including 862 cases)
Discovered by Olavi Kajander in 1988 May be responsible for: – –kidney stones – –hardening of arteries – –cancer – –diabetes – –tendonitis
20-200nm in size Debate in scientific community Appear to carry out all life processes – –CO 2 experiment Reproduce via binary fission or budding..\..\..\Desktop\Nanobac.wpl
Only 2 blood tests can detect nanobacteria NanoBac TX –Decrease coronary artery calcification scores by 58.5% after 4 months –In 20% of patients, the scores decreased to zero Not FDA Approved
Unproven Less than a dozen labs Controversial Slow rate of reproduction – –20 days vs 3 days to double – –Zero G: 4.6 times faster
An artificial Red Blood Cell Red Blood Cells –1L = 0.2L of oxygen (.004 mol/L) Artificial Red Blood Cells –1L = 21mol/L Enough for 36 hours of oxygen at rest Medical Applications Spacewalks, Deep Sea diving 1/2 L would be enough to hold your breath at the bottom of a pool for 4 hours or sprint at olympic speed for 12 minutes without taking a breath
Diamond BuckyBall 1000 atm Well within theoretical elastic limit Failures could be tolerated Leak over time into bloodstream Video from http://www.phleschbubble. com/album/beyond_huma n.html http://www.phleschbubble. com/album/beyond_huma n.html
Northwestern: Artificial Nerve cells using carbon nanofibers Spinal Cord injury –Astrocytes cause scarring –nanofibers made from peptide amphiphile molecules self-assemble into a scaffold which has amino acids that signal the body’s stem cells to differentiate into neurons –Prevents scar tissue from even forming –Scaffold nanofibers deteriorate in 4 weeks –Available for humans in 2-10 years
NASA Research - Repairing Radiation Damage –Infinitesimal Bullets –Detect protein from damaged cells and repair
Freitas: Microbivores –Artificial white blood cells –Fully eliminate pathogens and viruses in minutes compared to weeks or months –Greatly reduce need for doctors, drug companies, healthcare, etc.
Extend our lifespan to 1100 years, living in the body of a twenty year old the whole time Using nano-fabrication and self-assembly, it would be possible to produce chromosomes using an individual person’s genome as its base, but removing any defective genes, including the genes that cause aging. Clean out any other toxins and undegradable material that naturally remains in cells, contributing to aging
Nanoparticles are too small for the immune system to detect Polytetrafluoroethylene (PTFE) –20 nm - all rats died within 4 hours –150 nm - no adverse effects Crossing the blood-brain barrier Quantum Dots in cells