Group 5 – Nanomaterials in the Medical Field

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Transcript Group 5 – Nanomaterials in the Medical Field

 INTRODUCTION
 Definition of Nanomaterials
 Types of Nanomaterials
 Properties of Nanomaterials
 Why Nanotechnology in the Medical Field.
 APPLICATIONS
 Joint Replacements
 Medical Diagnostics
 Cancer Treatment
 Nanobacteria
 Providing Oxygen
 Nursing Neurons
 Future Possibilities
 Repairing Radiation damage
 Artificial White Blood Cells
 Extending Lifespan
 Safety Issues
 Conclusion
 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.
Types of Nanomaterials
Zero-Dimensional
One-Dimensional
Two-Dimensional
Nanopowder
Quantum dots
Nanowires
Nanorods
Nanotubes
Nanosheets
Super-lattice
 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.
Titanium Joints
 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
Human Osteoblasts
Become loose and painful
 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 17Y2O3-19Al2O3-64SiO2
(mole %) glass.
 Prepared by conventional glass melting technique.
 89Yttrium in this glass is non-radioactive.
– Activated by neutron bombardment to 90yttrium
 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 90yttrium then decays to stable
90zirconium.
Pre-Operation CT Scan
3 Months Post Treatment
Treatment: Theraspheres (Yttrium90 radiolabeled glass microspheres)
 Cancerous cells are poorly supplied with oxygen to
produce lactic acid.
– Therefore, these cells can be destroyed around 43oC.
– By contrast, normal cells can be kept alive even around 48oC.
 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 (Fe3O4) in a
CaO-SiO2 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.
After injection of ferri-/ferromagnetic particles,
it is exposed to alternating magnetic field.
 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.
 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
– CO2 experiment
 Reproduce via binary fission
or budding
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 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
 Red Blood Cells
– 1L = 0.2L of oxygen (.004 mol/L)
 Artificial Red Blood Cells
– 1L = 21mol/L




An artificial Red Blood Cell
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
 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
 Nanomaterials have great promise in the
medical field
 All safety concerns must be addressed on an
individual basis
 Effect on society must be considered
 Ethical Questions must be addressed