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Smart mater ials used in medical
applications
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Table of contents
1. General description of smart materials
2. Smart metallics used in medical applications
Intelligent titanium surfaces Nitinol (for Nickel Titanium Naval Ordnance Laboratory)
3. Smart ceramics used in medical applications
Hydroxyapatite Zirconia
4. Smart polymers used in medical applications
High-performance polyethylene Hydrogels Poly(methyl methacrylate) Polyglycolic acid LTL Color Compounders
5. Smart composites used in medical applications
Electrical resistance measurement in carbon-reinforced composites Piezo composites
6. New tendencies and ideas in smart materials used in medical applications
7. Conclusions
8. Bibliography
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1. General description of smart materials
1.1. What are smart materials?
Fig. 1.1. Evolution of materials
Science and technology have made amazing developments in the design of electronics and
machinery using standard materials, which do not have particularly special properties (i.e. steel,
aluminum, gold). Imagine the range of possibilities, which exist for special materials that have
properties scientists can manipulate. Some such materials have the ability to change shape or size
simply by adding a little bit of heat, or to change from a liquid to a solid almost instantly when near a
magnet; these materials are called smart materials.
Smart materials have one or more properties that can be dramatically altered. Most everyday
materials have physical properties, which cannot be significantly altered; for example if oil is heated
it will become a little thinner, whereas a smart material with variableviscositymay turn from a fluid
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which flows easily to a solid. A variety of smart materials already exist, and are being researched
extensively. These include piezoelectric materials, magneto-rheostatic materials, electro-rheostatic
materials, and shape memory alloys. Some everyday items are already incorporating smart materials
(coffeepots, cars, the International Space Station, eyeglasses) and the number of applications for
them is growing steadily.
Each individual type of smart material has a different property which can be significantly
altered, such as viscosity, volume, and conductivity. The property that can be altered influences what
types of applications the smart material can be used for.
There are a number of types of smart material, some of which are already common. Some examples
are as following:
Piezoelectricmaterials are materials that produce a voltage when stress is applied. Since thiseffect also applies in the reverse manner, a voltage across the sample will produce stress within
the sample. Suitably designed structures made from these materials can therefore be made that
bend, expand or contract when a voltage is applied.
Shape memory al loysandshape memory polymersare materials in which large deformationcan be induced and recovered through temperature changes or stress changes (pseudoelasticity).
The large deformation results due to martensitic phase change.
Magnetostrictivematerials exhibit change in shape under the influence of magnetic field andalso exhibit change in their magnetization under the influence of mechanical stress.
Magnetic shape memoryalloys are materials that change their shape in response to asignificant change in the magnetic field.
pH-sensiti ve polymersare materials that change in volume when the pH of the surroundingmedium changes.
Temperatur e-responsive polymersare materials which undergo changes upon temperature. Halochromicmaterials are commonly used materials that change their colour as a result of
changing acidity. One suggested application is for paints that can change colour to
indicatecorrosionin the metal underneath them.
Chromogeni c systemschange colour in response to electrical, optical or thermal changes.These includeelectrochromicmaterials, which change their colour or opacity on the application
of a voltage (e.g.liquid crystal displays),thermochromicmaterials change in colour depending
on their temperature, andphotochromicmaterials, which change colour in response to lightfor
example, light sensitivesunglassesthat darken when exposed to bright sunlight.
Ferrofluid
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Photomechanical materi alschange shape under exposure to light. Self -healing materialshave the intrinsic ability to repair damage due to normal usage, thus
expanding the material's lifetime
Dielectri c elastomers(DEs) are smart material systems which produce large strains (up to300%) under the influence of an external electric field.
Magnetocaloric materialsare compounds that undergo a reversible change in temperatureupon exposure to a changing magnetic field.
Thermoelectric materi alsare used to build devices that convert temperature differences intoelectricity and vice-versa.
Several well established and ongoing applications are today available for adaptive/active
materials in medicine that exploit the properties of shape memory and super elastic alloys, shape
memory polymers, active and resorbable bioceramics and bioglasses, biomimetic polymers and gels,
active (nano)particles, smart textiles, active optical fibers, etc.
Nevertheless, the continuously increasing capability to image and manage matter at the
atomic and molecular level enabled by a number of nanoscale tools such as scanning probes, self and
directed assembly, single molecule techniques, nanolithography and DNA-based technologies,
coupled with advanced theory, multiscale modeling and simulation approaches for nanophase and
nanostructured materials and smart nano/micro/meso-engineered devices and prostheses, is fuelling
relevant opportunities and entirely new perspectives to inbuilt smartness or intelligence in materials
and devices that would interject in a meaningful way with the body environment. These are opening
new frontiers in medical diagnostics, pharmaceuticals, therapies, and in implant and prostheses.
Specific areas of interest include new or creatively engineered materials, multi-scale cell
engineering for functional tissues and drug and gene delivery systems, new materials and systems for
medical diagnostics, implants and prostheses, and systemic interaction in the body environment
including biocompatibility and biofunctionality issues.
2. Smart metallics used in medical applications
2.1. Intelligent titanium surfaces
Researchers Say That Smart Metallic Surfaces May Lead to Better Prostheses
Researchers at the Universit de Montral with help from McGill University, the Institut National de
la Recherche Scientifique (INRS-EMT), Plasmionique Inc and the Universidade de So Paulo, have managed
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to chemically modify titanium to create so called intelligent surfaces. The new material can interact with
cells in the body and either promote healing or suppress their growth. It is believed that this research will lead
to smart prostheses that will help promote healing of tissue post implantation.
Dr. Nanci and colleagues applied chemical compounds to modify the surface of the common
biomedical metals such as titanium. Exposing these metals to selected etching mixtures of acids and oxidants
results in surfaces with a sponge-like pattern of nano (ultra small) pits. We demonstrated that some cells stick
better to these surfaces than they do to the traditional smooth ones, says Dr. Nanci. This is already an
improvement to the standard available biomaterial.
The researchers then tested the effects of the chemically-produced nanoporous titanium surfaces on
cell growth and development. They showed that the treated surfaces increased growth of bone cells, decreased
growth of unwanted cells and stimulated stem cells, relative to untreated smooth ones. In addition, expression
of genes required for cell adhesion and growth were increased in contact with the nanoporous surfaces.
Fig. 2.1. Control Ti-Uncontrolled growth of cells on a Titanium surface
Nano Ti-Controled growth of cells on a nanoporous Titanium surface
Uncontrolled growth of cells on an implant is not ideal. For example, when using cardiovascular
stents, it is important to limit the growth of certain cells in order not interfere with blood flow. Also, in some
cases, cells can form an undesirable capsule around dental implants causing them to fall. The scientists
demonstrated that treatment with specific etchants reduced the growth of unwanted cells.
2.2. Memory metal2.2.1. Introduction
In 1965, the first of a series of metal alloys of nickel and titanium was produced by the Naval
Ordnance Laboratory. These alloys are called Nitinol,
for Nickel Titanium Naval Ordnance Laboratory. Many of the alloys have a rather remarkable
property: they remember their shape. This "smart" property is the result of the substance's ability to
undergo a phase change - a kind of atomic ballet in which atoms in the solid subtly shift their
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positions in response to a stimulus like a change in temperature or application of mechanical stress. A
simple demonstation involves bending a sample, then exposing it to a source of heat like hot air or
hot water. The sample recovers its original shape as its temperature is raised above the temperature
corresponding to the phase change. This temperature may be tuned by varying the ratio of nickel to
titanium atoms in the solid by a few percent relative to a 1:1 ratio.
2.2.2. How it works
As noted above, Nitinol is an alloy of nearly equal numbers of nickel and titanium atoms,
with the exact amounts varied to match the temperature of the phase change to the application. The
alloy can exist in either of two structures (phases) at room temperature, depending on the exact ratio
of nickel to titanium atoms. The structure found above the temperature of the phase change possesses
the high symmetry of a cube and is called austenite; the structure found below the temperature of the
phase change is much less symmetric and is called martensite. In the martensite phase the material is
very elastic, while in the austenite phase the material is comparatively rigid.
Nitinol can be "trained" to have a new shape while in the austenite phase by deforming it into
the desired shape. As it then cools to below the phase transition temperature, the material enters the
martensite phase. In the martensite phase the shape can then be changed by mechanical stress: groups
of atoms that were "leaning" in one direction will accommodate the mechanical stress by "leaning" in
another direction, as allowed by the less symmetric structure. The sample will revert to the shape
enforced upon it while it was in the austenite phase by returning it to the austenite phase through an
increase in its temperature. The thermal energy acquired by the shape through heating it provides the
energy the atoms need to return to their original positions and the sample to its original shape.
Fig. 2.2. Phases of Nitinol in different treatment
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The transformation from austenite to martensite can be accomplished in 24 different ways.
These 24 ways of producing martensite from austenite are the result of the symmetric CsCl structure
having 6 equivalent face diagonal planes, each of which can shift in one of two directions and can
distort (shear) in one of two directions, 6 x 2 x 2 = 2.
Fig. 2.3. Modification of the crystal lattice during the transformation from Austenite to Martensite
Fig. 2.4. A spring made oshape memory metal in its
martensitephase.
Fig. 2.5. The same spring
stretched to a new shape.
Fig. 2.6. In warm water or
with a stream of hot air, the
spring returns to its
"trained" shape by heating it to
above the temperature of the
phase change into the more
rigid austenitephase.
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2.2.3. Applications
The biocompatibility of NiTi allows its use in many medical applications such as: vascular
stents, anchors for attaching tendons to bone, medical guidewires, medical guidepins, root canal files,
bendable surgical tools, and devices for closing holes in the heart.
Another important attribute of nitinol in medicine is itssuperelasticity.
Other shape memory materials include gold cadmium, copper-aluminum-nickel, copper-zinc-
aluminum, and iron-manganese-silicon alloys.
2.2.3.1. Orthodontic archwires.
The archwire of these braces used in orthodontia is made of memory metal to apply pressure
uniformly to the teeth.
Fig. 2.5. Braces of archwire made of memory metal
2.2.3.2. Flexible eyeglass frames.
Bending the memory metal eyeglass frames converts the metal from the rigid austenite
structure to the more flexible martensite structure. When this mechanical stress is removed, the
frames return to their original shape and austenite structure. See this exact pair of framesdistort
when exposed to liquid nitrogen.
Fig. 2.6. Eyeglass frames made of memory metal
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3. Smart ceramics used in medical applications
Ceramics are used as components of dental implants, hip implants, middle ear implants, and
heart valves. They are generally more chemically stable and inert than most metals due to their
chemical bonding.The most commonly used material are alumina, zirconia, bioglass, hydroxyapatite, and
tricalcium phosphate. These materials work well within the human body for several reasons. They are
inert, and because they are resorbable and active, the materials can remain in the body unchanged.
They can also dissolve and actively take part in physiological processes, for example, when
hydroxyapatite, a material chemically similar to bone structure, can integrate and help bone grow into
it. One proposed use for bioceramics is the treatment ofcancer. Two methods of treatment have been
proposed; treatment throughhyperthermia, and radiotherapy.
Fig. 3.1. Cell of hydroxyapatite
3.1. Classification of technical ceramics
Technical ceramics can also be classified into three distinct material categories:
Oxides: alumina, beryllia, ceria, zirconia Nonoxides: carbide, boride, nitride, silicide Composite materials: particulate reinforced, fiber reinforced, combinations
ofoxides and nonoxides.Each one of these classes can develop unique material properties because ceramics tend to be
crystalline.
3.2. Smart Biomaterials and their Applications
The range of applications of smart materials in the biomedical field has become increasingly
diverse over the past decade. The increasing complexity of modern smart biomaterials makes it
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difficult to identify broad application areas, or themes, where current research is providing, or has the
potential to provide, new or improved capabilities. A biomaterial may be defined as any natural or
synthetic substance or combination of substances (other than a drug) which can be used for any
period of time, as a whole or as a part of a system which treats, augments, or replaces any tissue,
organ, or function of the body . It is clear that biocompatibility is an essential requirement for any
implanted smart material or device. All other material requirements will depend on the particular
application. For permanent implants, resistance to abrasion and wear, fatigue strength, durability
(corrosion resistance), long-term dimensional stability and permeability to gases, water, and small
biomolecules can be critical. These include:
3.2.1. Hydroxylapatite, also called hydroxyapatite (HA), is a naturally
occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH), but is usually written
Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities. Hydroxylapatite is
the hydroxyl endmemberof the complex apatite group. The OH- ion can be replaced
by fluoride, chloride orcarbonate, producing fluorapatite orchlorapatite. It crystallizes in
the hexagonal crystal system. Pure hydroxylapatite powder is white. Naturally occurring apatites can,
however, also have brown, yellow, or green colorations, comparable to the discolorations of dental
fluorosis.
Hydroxylapatite can be found in teeth and bones within the human body. Thus, it is
commonly used as a filler to replace amputated bone or as a coating to promote bone ingrowth
into prosthetic implants. Although many otherphases exist with similar or even identical chemical
makeup, the body responds much differently to them. Coral skeletons can be transformed into
hydroxylapatite by high temperatures; their porous structure allows relatively rapid ingrowth at the
expense of initial mechanical strength. The high temperature also burns away any organic molecules
such as proteins, preventing an immune response and rejection.
Fig. 3.2. Flexible hydrogel-HA composite, which has a mineral-to-organic matrix ratio
approximating that of human bone.
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3.2.2. Use of Zirconia in Restorative Dentistry
Zirconia is being used on the artificial femoral heads for hip replacements. This makes the
part stronger and the heads are smaller so the patient experiences less trauma during the operation.
Besides hip replacements, zirconia is being used in shoulders, knee joints, spinal implants and
phalangeal joints. This is an amazing use of ceramic materials and it is making great strides in the
medical field. Who knows what they will come up with next.
Though zirconia has been available for use in restorative dentistry for several years, there has
been an increased interest recently in these materials. Zirconia based restorations are quite versatile
and can be used for crowns,bridges, and implantabutments in a variety of clinical situations if the
appropriate guidelines are followed..
CRYSTAL Zirconia is a modern dental ceramic replacement for the metal substructures used
under porcelain crowns and bridges. CRYSTAL brand Dental Zirconia is also translucent, which
gives the overlaid procelain a brighter more natural look. Because of it's stronger-than-steel
properties, Zirconia has been used for decades on the space shuttle and on the new high-tech brakes
on German sports cars and other industrial applications.CRYSTAL Zirconia is a new formulation of
medical grade zirconia material, packed into blocks and ground to a custom fit using state-of-the-
art dental milling machines, and then sintered in 1500 C oven till it is virtually unbreakable. In the
past, dentists used to say that crowns or bridges need to be replaced every five or ten years, but while
the porcelain may chip or need repair, a crown or bridge substructure created with CRYSTAL
Zirconia should last a lifetime, and includes alifetimewarrantywhen milled by a certified dental
laboratory.
CRYSTAL Zirconia is 100% biocompatible and because the body does not reject zirconia,
this material is the preferred modern material for medical applications. Unlike amalgams and metal
alloys used in the dentistry in the past, the body accepts zirconia as a natural material, so you dont
have to worry about allergies or adverse reactions.
Fig. 3.3. Fixed partial denture Fig. 3.4. Crystal Zirconia
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3.2.3. Ceramics and Medicine help Liver Cancer
As most people know traditional treatment for cancer usually involves chemotherapy which
can be very difficult for individuals. Usually this means a hospital stay and they will become sick
afterwards with vomiting, nausea and hair loss. Most patients understand that this is the plight that
they have to deal with when they go through these treatments and some will, but others decide it's
just too much to bear.
Because of this researchers looked for a new way to do some type of treatment so that people
would not have to suffer so much. Glass microspheres are the answer that was found. These are very
tiny and very thin -- some have compared them to a human hair saying they are smaller -- and they
are approved by the FDA and currently in use in several hospitals across the United States.
This is a very simple treatment and the individual can have it done as an outpatient. The
microspheres are inserted into the tumor using a catheter and the radiation is centralized to the tumor.
The malignant tumor is then addressed and there is minimal damage to the other tissue. Because it is
done this way, the individual doesn't have the normal after therapy symptoms and will only
experience fatigue for several weeks while the radiation is working.
3.3. Discussions and Conclusions
Ceramics are difficult to form into complicated geometries using high-temperature processes
in a cost-effective manner in small dental laboratories. Other processes are well suited for custom
operations. Hot-isostatic-pressing (HIP) has great advantages for creating standard shapes in a
reusable mold, such as prepable zirconia abutments for implants. For custom prostheses (crowns and
bridges), it is currently more practical to rely on milling operations or molding operations to form
dental shapes. CAD/CAM ceramic materials provide a unique option to start with almost defect-free
material, but they don't provide flexibility to regionally customize esthetics or other properties for a
restoration. That is a large part of the reason that CAD/CAM has not replaced much of traditional
ceramic fabrication technology. No alternative yet competes with the esthetic result of dental
porcelain being layered by an artistic ceramic technician to fully characterize a restoration. While one
can speculate that this is possible, this is not currently an option. When this is true, then CAD/CAM
might have much grander appeal.
The detection of ceramic defects before oral inserting the prostheses allows all the corrections
in order to avoid the fracture of the ceramic component. The fractures that occur within the structure
of these prostheses were motivated by the elasticity module of the ceramics and by the defects within
the ceramic layers. Early detection of substance defects within these layers allows for optimal
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corrections before inserting them and applying masticatory stress together with reduction of fractures.
Also some of the defects are situated superficial enough and cervical, namely in the maximum
tension area recorded during mastication with high risks of fracture at this level.
4. Smart polymers used in medical applications
Fig. 4.1. Polyethylene chain picture
` A polymer is a large molecule (macromolecule) composed of repeating structural units.
These sub-units are typically connected covalent chemical bonds(sharing of pairs of
electrons between atoms).The polymer can be natural(as examples shellac,amber,natural rubber) or
synthetic(examples as synthetic rubber ,nylon ,PVC polystyrene,polyethylene,silicone,polypropylene
and many others).
What makes a polymer smart? Maybe because it can be used in various applications industry
,medicine , sports , agriculture and for his properties that makes him biodegradable , inert or bioactivif we refer to medicine.
For instance high-performance polyethylene (HPPE or ultra-high-molecular-weight polyethylene)
used in total or partial joint replacement implants, hydrogels used for scaffolds tissue engineering or
Poly(methyl methacrylate) (PMMA) for bone cement and of course many other polymers.
Fig. 4.2. Various polymers in their crude form
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4.1. High-performance polyethylene (HPPE or ultra-high-molecular-weight
polyethylene)
Is a subset of the thermoplastic polyethylene. It has extremely long chains, chains that makes
him transfer load more effectively from here result a very tough material, with the highest impact
strength of any thermoplastic presently made.
HPPE is a type ofpolyolefin. It is made up of extremely long chains of polyethylene, which
all align in the same direction. It derives its strength largely from the length of each individual
molecule (chain). Van der Waals bondsbetween the molecules are relatively weak.
It is highly resistant to corrosive chemicals with exception ofoxidizing acids; has extremely low
moisture absorption and a very low coefficient of friction; is self-lubricating; and is highly resistant
to abrasion, in some forms being 15 times more resistant to abrasion than carbon steel. Its coefficient
of friction is significantly lower than that ofnylon and acetal, and is comparable to that
ofpolytetrafluoroethylene (Teflon).
Fig. 4.3.Structure of HPPE, with n greater than 100,000 and knee implant
4.1.1. Medical applications
Used in total or partial joint replacement such as hip , knee or intervertrebal implants.
4.2. Hydrogels
Hydrogel (also called aquagel) is a network of polymer chains that are hydrophilic,
sometimes found as a colloidal gel in which wateris the dispersion medium. Hydrogels are
highly absorbent (they can contain over 99.9% water) natural or synthetic polymers. Hydrogels also
possess a degree of flexibility very similar to natural tissue, due to their significant water content.
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Fig. 4.4.Porous hydrogel structure
4.2.1. Applications
currently used as scaffolds in tissue engineering. When used as scaffolds, hydrogels maycontain human cells to repair tissue.
hydrogel-coated wells have been used for cell culture[2] environmentally sensitive hydrogels which are also known as 'Smart Gels' or 'Intelligent
Gels'. These hydrogels have the ability to sense changes of pH, temperature, or the
concentration of metabolite and release their load as result of such a change.
as sustained-release drug delivery systems hydrogels that are responsive to specific molecules, such as glucose , can be used
as biosensors
Fig. 4.5. Scaffold structures are built up from layers of cross-hatched hydrogel strands
used in disposable diapers where they absorb urine, or in sanitary napkins contact lenses (silicone hydrogels)
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EEG and ECG medical electrodes using hydrogels composed ofcross-linkedpolymers(polyethylene oxide)
dressings for healing ofburn or other hard-to-heal wounds. Wound gels are excellent forhelping to create or maintain a moist environment.
4.3. Poly(methyl methacrylate) (PMMA)
Poly(methyl methacrylate) is a transparent thermoplastic, often used as a light or shatter-
resistant alternative to glass.
PMMA is an economical alternative to polycarbonate (PC) when extreme strength is not
necessary. It is often preferred because of its moderate properties, easy handling and processing, and
low cost, but behaves in a brittle manner when loaded, especially under an impact force, and is more
prone to scratching compared to conventional inorganic glass.
PMMA is methyl methacrylate monomer polymerization. Presents high mechanical strength,
toughness.
Fig. 4.6. Structure of PMMA
4.3.1. Applications
PMMA has a good degree of compatibility with human tissue, and can be used forreplacement intraocular lenses in the eye
In orthopedic surgery, PMMA bone cement is used to affix implants and to remodel lostbone. It is supplied as a powder with liquid methyl methacrylate (MMA).Although PMMA
is biologically compatible, MMA is considered to be an irritant and a possible carcinogen
.Although sticky, it does not bond to either the bone or the implant, it primarily fills the
spaces between the prosthesis and the bone preventing motion. A big disadvantage to this
bone cement is that it heats to quite a high temperature.
Dentures are often made of PMMA, and can be color-matched to the patient's teeth
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In cosmetic surgery, tiny PMMA microspheres suspended in some biological fluid areinjected under the skin to reduce scars permanently
A large majority of white Dental filling materials (composites) have PMMA as their mainorganic component.
Fig. 4.7. Sacroplasty, a bone gluepolymethylmethacrylate (PMMA) is injected into the
fracture
4.4. Polyglycolic acid (PGA)
Fig. 4.8. Ring-opening polymerization of glycolide to polyglycolide
Polyglycolic acid (PGA) is a biodegradable, thermoplastic polymerand It can be prepared
starting from glycolic acidby means ofpolycondensation orring-opening polymerization.
Polyglycolide is characterized by hydrolytic instability and the degradation process is erosive
and appears to take place in two steps during which the polymer is converted back to its monomer
glycolic acid: first water diffuses into the amorphous (non-crystalline) regions of the polymer matrix;
the second step starts after the amorphous regions have been eroded, leaving the crystalline portion of
the polymer susceptible to hydrolytic attack.
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Silver ion AM does not kill microorganisms in the sense of a disinfectant such as chlorine
bleach. Instead the AM suppresses cellular reproduction by disrupting the energy production
mechanism of the cell, preventing DNA replication in the cell, and weakening the cell wall. Silver
ions bound in an inorganic matrix are incorporated into a plastic. The silver ions migrate to the
surface of the plastic in the presence of trace amounts of moisture and then move into the cell. As a
result the count of microorganisms decreases over a period of hours. As an indication of
effectiveness, standardized tests such as JIS Z 2801 utilize specific bacterial strains to determine the
reduction in bacteria count on treated surfaces over a 24 hour period. In this test very large reductions
of 99.9% or greater.
Fig. 4.10.ColorRx Antimicrobial (AM)
5. Smart composites used in medical applications
The composite materials considered here are solid objects with a macrostructure. The
constituents of these, solids can be observed with the naked eye. Solid objects are said to be smartif
they embody additional functionality capabilities beyond their inherent structural attributes. These
capabilities might be attributed to an embedded network of interconnected sensors, actuators and
computers, for example. Synthetic inhomogeneous materials with these capabilities comprise the
basis for a new generation of materials. These materials have the potential to revolutionize many
types of products, and usher into existence unforeseen manufactured goods.
Humankinds traditional quest for superior materials may be satisfied in the near future by
ideas furnished by Mother Nature. The design and manufacturing methodologies needed for creating
new generations of materials will come from a meticulous study of flora and fauna.
The future lies with the development of synthetic materials that mimic naturally occurring biological
materials.
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5.1. Cure monitoring
Today, engineering plastics and polymer matrix composites (PMCs) are widely used in
consumer and leisure products such as golf clubs, fishing rods, skis, and tennis rackets. Fiber-
reinforced plastics (FRPs), particularly, are the most promising composite materials for airplanes,
space structures, and military ships. Thermosetting and thermoplastic polymers are common
materials used in FRPs.
In the molding process for polymers, a liquid resin becomes solid. As for thermosetting
polymers, a monomeric liquid resin becomes a cross-linked rigid solid and a tightly bound three-
dimensional network is produced. This process is called cure. Thermoplastics do not need to
becured because they are not cross-linked. In these advanced engineering materials, the integrity of
the product is very important for certifying the performance. The quality of a product strongly
depends on the profiles of the control parameters such as the temperature and pressure in the molding
process. Therefore, many researchers have developed techniques for optimizing the molding process.
The monitoring technique is essential for the optimal control system of the molding process. The cure
monitoring technique, especially has been an important focus because the cure reaction of a
thermosetting FRP is too complicated to predict. Techniques for monitoring the molding process of
thermosetting FRPs are not discussed. However, it should be remembered that some of the
techniques that monitor the mechanical, optical, and electrical properties, can also be applied to
monitor the state of solidification in the process of molding thermoplastic polymers.
5.2. Electrical Resistance Measurement in Carbon-Reinforced Composites
The technique for health monitoring by measuring electrical resistance has become attractive
since the late 1980s for carbon-reinforced composites (90). This technique measures changes in
electrical resistance when strains or damages are applied to the composites. Like the tagging
technique, the advantage of this technique is that there is no need for embedded sensors for in situ
monitoring. In addition, the mechanical properties of the composites are not affected by using this
monitoring technique because the carbon reinforcements work as sensors. Recently, applications
have focused on three types of composites; carbonfiber- reinforced concrete, carbon-fiber-reinforced
polymers (CFRPs), and carbon fibercarbon matrix (C/C) composites (91). The self-monitoring
functions of carbon-reinforced composites are aimed at strain and damage monitoring. These
functions result from changes in the electrical paths and in the conductivity of carbon. Short carbon-
fiber-reinforced concrete consists of low conductive concrete and carbon fibers at a low volume
fraction. In continuous carbon-reinforced polymers, the electrical paths are composed of the carbon
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fibers due to the nonconductivity of polymers. A current flows overall in the C/C composite because
it has conductivity in the fiber and matrix. The electrical paths in the composites are changed by
damages such as fiber breaks, delaminations, matrix cracks, and debonding between the fiber and
matrix. The mechanism of the variation of electrical resistance differs among these composites due to
their different electrical paths.
5.3. Piezo Composites
1-3 Piezo Composites have become the material of choice for many high performance
ultrasound transducer since it was invented by R.E. Newnham and L.E. Cross in the late 1970's .A variety of piezo composite materials can be made by combining piezo ceramic elements with a
passive polymer such as epoxy or active polymer. Piezo-composites are classified according to their
connectivity (such as 2-2, 1-3, 0-3 etc.,). Connectivity is defined as the number of dimensions
through which the material is continuous. It is conventional for the first digit to refer to the
piezoelectrically active phase.
Prof. Newnham defined the family of interconnectivity of piezo electric composites as shown
in one of his drawn pictures below.
Today the most piezo composites on the market are with the 1-3 and 2-2 connectivity used in
ultrasound transducers, actuators and sensors.
1-3 piezo composites advantages over standard bulk piezo ceramics are in general:
lower acoustic impedance, 1-3 piezo composites are available with acoustic impedancebetween 8MRayl and 26MRayl
higher coupling coefficient of typically 0.63 to 0.70 compared with 0.54 of bulk material higher bandwidth and lower Qm
Disadvantages of piezo composites over bulk piezoceramic components are in general the
higher costs and the often limited temperature operating range.
The typical applications for 1-3 piezo composites are
Medical Diagnostic Ultrasound Non Destructive Testing NDT SONAR, mostly defense oriented for high performance Flow Control and Air Ultrasound
The biggest single market for the 1-3 piezo composite is the medical diagnostic ultrasound
market which is using more 1-3 piezo composite than the other markets combined. Today's medical
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ultrasound imaging systems would be not possible without the advancements in 1-3 piezo
composites.
Smart Material is manufacturing and distributing piezo composite material with 2-2
connectivity (theMFC) and
1-3 connectivity.
Smart Material is utilizing different manufacturing technologies to meet to meet the typical
requirements of the applications for 1-3 piezo composites as outlined above which are listed under
Types Available:
1-3 Fiber Composites with Random Pixel Distribution
1-3 Fiber Composites with Regular Pixel Distribution
1-3 Standard Dice&Fill Composites
Utilizing different manufacturing technologies for 1-3 piezo composites allows Smart
Material to provide 1-3 composites for frequencies ranging from 40kHz to 10 MHz, with fill factor
ranging from 25% to 80% and sizes up to 100mm by 100mm (4inches by 4 inches).
6. New tendencies and ideas in smart materials used in medical applications
There are two diverting ideas that define a direction in the research of new materials field:
Creating a universal material able to respond to all the requirements (this idea is purely sci-fifor now);
Creating the material needed in the place needed, with the structure needed, in the quantitiesneeded (this would be possible by manipulating the matter at an atom scale).
Implementing a system with an automated response in various fields present significant
advantages by monitoring certain signals and responding accordingly when it detects limit overruns.
Adding to the system the possibility of learning certain patterns, which is possible today using neural
networks, enhances the autonomy and efficiency. Applying these new findings from science and
technology in medicine requires miniaturization and keeping the interactions with the environment
strictly limited to the purpose these assemblies were created for.
Smart materials are exactley this, combining the sensing activity with the actuating one. The
disadvantage is that they usualy respond to only one type of signal and respond in only one way. By
combining in certain ways different types of smart materials there is a posibility of reducing this
disadvantage.
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Regenerative medicine, diagnostics and drug delivery could profit from intelligent
biomaterials. For example enzyme-responsive materials have the potential to detect, respond to, and
ultimately repair biological processes by injecting cell-scaffold that gels when triggered by tissue
fluid enzymes. Also the flow of molecules into (and out of) polymer particles can be controlled by
very specific enzyme switches - the first steps in making truly bio-responsive materials. The goal for
now is to mimic the in-vivo feed-back systems that control enzyme activity.
Carbon nanotubes is known to be highly electrically conductive, this being used to create a
connection with the neuronal cell membranes. Unlike the metal electrodes that are currently used in
research and clinical applications, the nanotubes can create shortcuts between the distal and proximal
compartments of the neuron, resulting in enhanced neuronal excitability. From a study conducted in
Switzerland resulted this finding is relevant for the emerging field of neuro-engineering and
neuroprosthetics, the nanotubes could be used as a new building block of novel "electrical bypass"
systems for treating traumatic injury of the central nervous system. Carbon nano-electrodes could
also be used to replace metal parts in clinical applications such as deep brain stimulation for the
treatment of Parkinson's disease or severe depression. And they show promise as a whole new class
of "smart" materials for use in a wide range of potential neuroprosthetic applications.
There are three fundamental obstacles to developing reliable neuroprosthetics:
1) stable interfacing of electromechanical devices with neural tissue,2) understanding how to stimulate the neural tissue, and3) understanding what signals to record from the neurons in order for the device to make an
automatic and appropriate decision to stimulate.
The new carbon nanotube-based interface technology discovered together with state of the art
simulations of brain-machine interfaces is the key to developing all types of neuroprosthetics -- sight,
sound, smell, motion, vetoing epileptic attacks, spinal bypasses, as well as repairing and even
enhancing cognitive functions.Near-infrared (NIR) light (which is just beyond what human can see) penetrates through the
skin and almost four inches into the body, with great potential for diagnosing and treating diseases.
Low-power NIR does not damage body tissues as it passes. A new smart polymer that responds to
low-power NIR light breaks apart into small pieces that seem to be nontoxic to surrounding tissue. A
hydrogel with the new polymer could release medications or imaging agents when hit with NIR. This
is the first example of a polymeric material capable of disassembly into small molecules in response
to harmless levels of irradiation.
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Fig. 6.1. Near-infrared light
Fig. 6.2. Molybdenum oxide wheel molecule
Working out how nano-particles are built is key to developing new intelligent materials,
electronic devices, and understanding the bio-machinery that operates in living cells. The ability to
control this self-assembly has profound consequences for the development of new technologies as
well as understanding the basis for complex chemistry, and for example, the origins of life.
A team of experts at Glasgow devised an experiment which enabled them to observe
molecules being constructed around what appeared to be a transient template cluster.
The experiment involved the construction a flow reactor system for the assembly of the nano-
particles under dynamic flowing conditions. This new experimental approach allows self-assembly
being examined in a new way at the nano-level, giving rise to unprecedented mechanistic information
unmasking the complexities of molecular self-assembly (the process by which objects form a
particular arrangement without any external manipulation).
During the experiment, the researchers observed the self-assembly of molybdenum oxidewheel molecules around an intermediate structure in the centre of the wheel which they found to be
the template or scaffold used to construct the larger molecule. Following completion of the
molybdenum oxide wheel molecule, which is just 3.6 nanometres in diameter, the template was
ejected, freeing it to repeat the process. The researchers were able to photograph this process and
the template using X-ray crystallography.
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Understanding the assembly process is vital if we are to create a new range of functional
nano-objects.
A tiny cage of gold covered with a smart polymer, it
responds to light, opening to empty its contents, and
resealing when the light is turned off.
The principle on which it is based on is fairly intuitive
described in the next few steps.
Attach a smart polymer to a gold nano-cage with thepores at the corners.
To load the cages, shake them in a solution of thedrug at a temperature above the polymer's critical
temperature.
Fig. 6.2. Nano cage polymer
Let the cages cool, so that the polymer chains stand up like brushes, sealing the cage's pores. To release the drug, expose the cages to laser light (the lightning bolt) at their resonant
frequency, heating them just enough to drive the polymer over its critical temperature.
The polymer chains will collapse, opening the pores, and releasing the drug. The cage can beresealed simply by turning off the light.
Medicines sometimes have to be administered in extremely small quantities. Just a few tenths
of a milliliter may be sufficient to give the patientthe ideal treatment. Micro-pumps greatly facilitate
the dosage of minute quantities.
The peristaltic pump is a highly complex
system. It contracts in waves in a similar way to the
human esophagus, and thus propels the liquid along
it changes shape of its own accord. To achieve
this, researchers had to use a whole range of
different materials and special material composites.
They used lead-zirconate-titanate (PZT) films that are joined in a suitable way with bending
elements made of carbon-fiber-reinforced plastic and a flexible tube.
PZT materials change their shape as soon as you apply an electric field to them. This makes it
possible to control the pump system electronically. Special adhesives additionally hold the various
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components of the pump system together. Thanks to the special control electronics, tiny quantities
can be pumped accurately through the system.
7. Conclusions
The most sophisticated class of smart materials in the foreseeable future will be that whichemulates biological systems. This class of multifunctional materials will possess the capability to
select and execute specific functions intelligently in order to respond to changes in the
local environment. Furthermore, these materials could have the ability to anticipate challenges based
on the ability to recognize, analyze, and discriminate. These capabilities should include self-
diagnosis, self-repair, selfmultiplication, self-degradation, self-learning, and homeostasis.
The intelligence to be imbued in a synthetic material developed by humankind should emulate
the intelligent attributes found in biological systems. These attributes do not require human
involvement, and they function autonomously, as evidenced by self-learning, selfdegradation, and
regeneration. Thus the rusting of iron in a humid environment could be considered to be a simple
form of self-degradation. Other functions could include the availability to recognize and subsequently
discriminate, redundancy, hierarchical control schemes, and the election of an appropriate action
based on sensory data.
Furthermore, a material that has been damaged and is undergoing a process of self-repair
would reduce its level of performance in order to survive. This intelligence should be inherent in
future generations of smart materials.
So, were looking forward to the future, waiting impatiently to see what wonderful discoveries will
appear in the materials domain.
8. Bibliography
Encyclopedia of Smart Materials by Mel Schwartz
http://accurx.net/Pharmacogel.html http://www.narang.com/laboratory-products/burets/index.php http://medgadget.com www.mrsec.wisc.edu.com www.wikipedia.com www.smart-material.com
http://accurx.net/Pharmacogel.htmlhttp://accurx.net/Pharmacogel.htmlhttp://www.narang.com/laboratory-products/burets/index.phphttp://www.narang.com/laboratory-products/burets/index.phphttp://medgadget.com/http://medgadget.com/http://www.mrsec.wisc.edu.com/http://www.mrsec.wisc.edu.com/http://www.wikipedia.com/http://www.wikipedia.com/http://www.smart-material.com/http://www.smart-material.com/http://www.smart-material.com/http://www.wikipedia.com/http://www.mrsec.wisc.edu.com/http://medgadget.com/http://www.narang.com/laboratory-products/burets/index.phphttp://accurx.net/Pharmacogel.html7/27/2019 Smart Material in Medicine
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http://bme.usc.edu/UTRC/info/pubs/Electroceramics.pdf http://www.siemens.com/innovation/en/publikationen/publications_pof/pof_spring_2003/mat
erials_articles/bioengineering.htm
http://www.mdtmag.com/tags/Products/Materials/?page=2http://www.mdtmag.com/Products/2012/02/Antimicrobial-Grades-of-Polymer-Offering-Expanded/
http://www.natureasia.com/asia-materials/highlight.php?id=657 http://sciencenotes.ucsc.edu/1001/pages/hydrogel/hydrogel.html http://pmr.cuni.cz/Data/files/PragueMedicalReport/PMR%2007-01%20Pilathadka.pdf http://www.tmj.ro/article.php?art=8354908538128542 www.sciencedaily.com www.physorg.com www.design-technology.com www.rsc.org www.nitinol.com
http://bme.usc.edu/UTRC/info/pubs/Electroceramics.pdfhttp://bme.usc.edu/UTRC/info/pubs/Electroceramics.pdfhttp://www.siemens.com/innovation/en/publikationen/publications_pof/pof_spring_2003/materials_articles/bioengineering.htmhttp://www.siemens.com/innovation/en/publikationen/publications_pof/pof_spring_2003/materials_articles/bioengineering.htmhttp://www.siemens.com/innovation/en/publikationen/publications_pof/pof_spring_2003/materials_articles/bioengineering.htmhttp://www.siemens.com/innovation/en/publikationen/publications_pof/pof_spring_2003/materials_articles/bioengineering.htmhttp://www.mdtmag.com/tags/Products/Materials/?page=2http://www.natureasia.com/asia-materials/highlight.php?id=657http://www.natureasia.com/asia-materials/highlight.php?id=657http://sciencenotes.ucsc.edu/1001/pages/hydrogel/hydrogel.htmlhttp://sciencenotes.ucsc.edu/1001/pages/hydrogel/hydrogel.htmlhttp://pmr.cuni.cz/Data/files/PragueMedicalReport/PMR%2007-01%20Pilathadka.pdfhttp://pmr.cuni.cz/Data/files/PragueMedicalReport/PMR%2007-01%20Pilathadka.pdfhttp://www.tmj.ro/article.php?art=8354908538128542http://www.tmj.ro/article.php?art=8354908538128542http://www.sciencedaily.com/http://www.sciencedaily.com/http://www.physorg.com/http://www.physorg.com/http://www.design-technology.com/http://www.design-technology.com/http://www.rsc.org/http://www.rsc.org/http://www.nitinol.com/http://www.nitinol.com/http://www.nitinol.com/http://www.rsc.org/http://www.design-technology.com/http://www.physorg.com/http://www.sciencedaily.com/http://www.tmj.ro/article.php?art=8354908538128542http://pmr.cuni.cz/Data/files/PragueMedicalReport/PMR%2007-01%20Pilathadka.pdfhttp://sciencenotes.ucsc.edu/1001/pages/hydrogel/hydrogel.htmlhttp://www.natureasia.com/asia-materials/highlight.php?id=657http://www.mdtmag.com/tags/Products/Materials/?page=2http://www.mdtmag.com/tags/Products/Materials/?page=2http://www.siemens.com/innovation/en/publikationen/publications_pof/pof_spring_2003/materials_articles/bioengineering.htmhttp://www.siemens.com/innovation/en/publikationen/publications_pof/pof_spring_2003/materials_articles/bioengineering.htmhttp://bme.usc.edu/UTRC/info/pubs/Electroceramics.pdfRecommended