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Biomaterials
are general introductions to the uses of artificial materials in the human body
for the purpose of aiding healing, correcting deformities and restoring lost
function. This introduction has really facilitated the functional cells in
humans and industries basically on its application.
Enhancing on the field developments
since the successful last edition, biomaterials continues in its tradition as
an outgrowth of an undergraduate course for senior students in Biomedical
Engineering developed by the authors with 60years of combined experience, the
authors have emphasized the fundamental material science, structure,
properties, relationships and biological responses as a foundation for a wide
array of biomaterials applications.
Biomaterials have also accelerated the
treatment of injures or disease, it has also been found that a variety of
non-living materials benefits from the biomaterial.
MEANING OF BIOMATERIALS
A
biomaterial is a synthetic material used to replace part of a living system or
to function in intimate contact with living tissues. According to the Clemson
University Advisory Board of Biomaterials defined biomaterial to be a
systematically and pharmacologically inert substance designed for implantation
within or incorporation with living system.
Biomaterials can also be defined as any
substance or combination of substances other than drugs, synthetic or natural
in origin which can be used for any period of time which augments or replaces partially
or totally any tissue, organ, or any function of the body in other to maintain
or improve the quality of life of an individual.
CLASSIFICATION OF BIOMATERIALS
In the classification of biomaterials,
it is considered that tissues react towards the implant in a variety of ways
depending on the material type. The mechanism of tissues when they react
depends on the tissue response to the implant surface. There are three terms or
way in which biomaterials can be classified in order of representing the tissue
responses;
a. Bio-Inert
Biomaterial:
Bio-inert
refers to any material that responds minimally when it comes in contact with
the human body and also with its environment. Bio-inert materials are not fully
dependent on their functions but on external factors. It has no reaction or
cause no reaction with the host. They are rather used originally for vascular
surgeries due to its need for surfaces which do not cause clotting of the
blood. Most materials are not completely Bio-inert and no synthetic material is
bio-inert. Example of bio-inert substances or close to it includes titanium,
aluminum, vanadium alloy (used in hip replacement), Phosphoryl Chlorine (PC) (used
in contact lenses), Diamond, etc.
b. Bioactive
Biomaterials:
Bioactive
refers to a material which upon being placed within the human body interacts
with the surrounding. They maximally interact compared to that of the bio-inert
biomaterials. They interact with the surrounding bone and in some cases even
with the surrounding tissues. This occurs through a time-dependent kinetic
modification of the surface, triggered by their implantation within the living
bone. When Bioactive implant reacts with the surrounding body fluid, there is
formation of the biologically active carbonate apatite (CHAP) layer on the
implant that is chemically and in crystallographically equivalent to the
mineral phase in bones. Examples of these materials include synthetic
Hydroxyapatite [Ca10(PO4)6(OH)2],
glass ceramic A-W and bioglass.
c. Bioresorbable
Biomaterial:
Bioresorbable
biomaterial refers to a material that upon placement within the human body
starts to dissolve (resorbed) and slowly replaced by advancing tissues (such as
bone). Common examples of these materials includes Tricalciumphosphate [Ca3(PO4)2]
and polylactic-polyglycolic acid copolymers. Calcium oxide, Calcium carbonate
and gypsum are other common materials that have been utilized during the last
three decades.
APPLICATIONS OF BIOMATERIALS
Biomaterials
can be applied using the following methods;
a. Cardiovascular
Medical Services
Heart valves, endovascular stents,
vascular grafts, stents grafts, and other cardiovascular grafts are common
medical devices in cardiovascular application. The most major form of vasvular
heart disease includes aortic, and mitral valve. The most common type of valve
disease and most frequent indication for valve replacement is calcific aortic
stenosis obstruction at the aortic valve secondary to age-related calcification
of the cusps of a valve that was previously anatomically normal. Different
polymers and metals with or without coating can be applied in this category
example Titanium, Polytetrafluroethylene, etc
b. Tissue
engineering scaffolds
This
method of application is one of the most important ways to achieve tissue for
repair or replace applications. Its goal is to design and fabricate
reproducible bioactive and bioresorbable 3-D scaffolds with tailored properties
that are able to maintain their structure and integrity for predictable times, even
under load bearing conditions. Scaffolds can be applied in different
fabrications and biomaterial selection depending on the target organs and its
cells of degradation should provide a sufficient mechanical environment and
should facilitate cell attachment, proliferation and migration, waste nutrient
exchange, vascularization and tissue in growth.
c. Ophthalmologic
application
Vision
impairment/low vision, blindness, refractive error [myopia and hyperopia], astimagtism,
presbyopia, cataracts, primary open-angle glaucoma, age related macular
degeneration [AMD] and diabetic retinopathy are common ophthalmologic diseases.
To improve the life of these patients, many implants have been applied.
d. Bioelectrodes
and biosensor
Bioelectrodes
are sensors used to transmit information in and out of the body surface or
transcutaneous electrodes used to monitor or measure electrical events that occur
in the body are considered monitoring or recording electrodes. Typical
application for recording electrodes includes electrocardiography information
into or out of the body. These Bioelectrodes are mainly applied in cardiology
and neurology application.
e. Burn
dressing and skin substitutes
Skin
is the largest organ that protects the body from micro-organisms and external
factors, integrates complex sensory nervous and immune systems, controls fluid
loss, and serves important aesthetic or function. Deep skin injuries due to
deep cuts, burns or gloving injuries can cause significant physiological
derangement, expose the body to a risk of systemic infection and become a life
threatening problem. So the need of skin substitutes depend on wound depth is
felt.
f. Sutures
Suture
is any strand of material that is used to ligate blood vessels or approximate
tissue. Ligature is used to achieve hemostasis or to close a structure to
prevent leakage. The suture device is comprised of: the suture strand, the
surgical needle, and the packaging material used to protect the suture and the
needle during storage. The ideal suture must be bio-compatible, sterile,
compliant, adequate knot/straight strength, secure and stable knot, strength
and mass loss profile adequate for proposed usage, low friction, adequate
needle attachment strength, atraumatic needle design, non-electrolytic,
non-capillary, non-allergenic, non-carcinogenic, minimally reactive, uniform
and predictable performance.
g. Dental
Material
Restorative
materials have been used as tooth crowns and root replacement. Four groups of
materials which are used in dentistry are mostly metals, ceramics, polymers,
and composites. Despite recent advancement in materials science and dentistry,
there is still no proper material for restorative dentistry. Characteristics of
an ideal restorative material are listed below:
1. Be
Bio-compatible
2. Bond
permanently to tooth structure or bone.
3. Match
the natural appearance of tooth structure and other visible tissues.
4. Exhibits
properties similar to those of tooth enamel, dentin and other tissues.
5. Be
capable of initiating tissue repair or regeneration of missing or damaged
tissue.
Dental
materials can be classified into preventive and restorative materials.
Preventive materials can be primarily used for anti-bacterial effect while the
of the restorative material can be used for both long and short term
application.
PRODUCTION OF BIOMATERIALS
Biomaterials
can be produced in different forms but mainly from agriculture. Agricultural
residues are useful in the transformation of several chemicals into high
value-added products using a wide range of novel chemical or microbiological
treatment to optimize their use. The production of biomaterials from a range of
agricultural use have been achieved through extraction and fermentation processes
either with pre-treatment to obtain fermentable sugars or without pre-treatment
using solid state fermentation. The product such as the fermentable sugar are
used feedstock in biotechnological processes in other to obtain bio-energy in
the form of heat, electricity, bio-fuels, as well as high added value
biomaterials.
GLOBAL PERSPECTIVE ON INDUSTRIALIZATION
OF BIOMATERIALS
In more than 50 years, three generations
of biomaterials have been used and the last generation concerns cells and gene
activating materials starting from the mid-twentieth century, the evolution of
biomaterials advanced with the used of polyester, plastics, metal alloys,
ceramics, etc. starting with the first generation, it is discovered that a key
feature of this biomaterials is their biological inertness, which minimizes the
body response to the foreign materials, HA-Bioactive glasses, and glass
ceramics, molecularly tailored resorbable polymers, etc. to the third
generations the work is being undertaken on cell and gene activating materials.
Due to the increased industries, an increase in biomaterials market was worth
about 4.5 billion US Dollar in 2008, which represented 33% of the global market
and in 2014 the growth kept increasing quickly. The biomaterials therefore
improved the growth of technologies, quality of life as well as increase in
innovation of companies domestically and internationally.
EFFECTS OF GLOBAL PERPESTIVE ON
INDUSTRALIZATION OF BIOMATERIALS
According
to Olumurejiwa A. Fatunde, Sujita K. Bhatia (2012, pg17) reviewed equipments
donated from one industrialized nation such as the United State will have a
dual effect of ensuring that all imported or donated equipments meets a certain
standards of excellence (including appropriateness for the giving context
especially in rural areas) and promoting local generation of alternative.
APPLICATION OF GLOBAL PERSPECTIVE ON
INDUSTRIES
Biomaterials
have wide spread application in Orthopedic implants, which are usually used in
Orthopedic procedures, such as Orthobiologics, bioresorbable tissue fixation
products, joint replacement, etc. Industries have been widely increased
basically on the various application areas in terms of consumption plastic
surgery application is primed imposed the fastest similar period CAGR of 22.3%
and reached a projected 10.5 billon US dollar by 2023. This boost can be seen
based on the material types and major application area.
BIOMETRIC BIOMATERIALS AND TISSUE
ENGINEERING AND ITS GLOBAL PERSPECTIVE
The
fields of biometric biomaterials and tissue engineering has played a crucial
role in the advancement of health care, it has also not only repaired injured
tissues or organs but rejuvenated and regenerated them.
CLINICAL TRANSLATION OF BIOMATERIALS
In
the inter-disciplinary field of biomaterials, the phenomenological interaction
of a biological cell on a material substrate under normal culture condition is
broadly known and many approaches have been taken either the tailored substrate
modulus or surface ability in effort to enhance cell material interaction. In
recent researches, it has been discovered that biomaterials are translated
involving or using the combination of external physical cues and instructive
materials to guide tissue repair and regeneration.
KEY FACTORS CONSIDERED IN CLINICAL
TRANSLATION PROCESS
In order to improve the
industrialization and commercial areas, there are steps needed to be taken to
enhance clinical translation in biomaterials:
i.
Selecting translational projects
ii.
Accessing the unmet medical needs
iii.
Transforming basic knowledge into ideas.
iv.
Cutting age technologies from innovative
fundamental ideas.
EFFECTS OF BIOMATERIALS ON CLINICAL
TRANSLATION PROCESS
Biomaterials
may act as physical support at times providing a space in which biological
systems manifest their inherent characteristics. Biomaterials have become an
integral part of several industrial process and products, it is their medical
use in the body that facilitates recuperation. According to Wozney et al. (1988), some beneficial outcomes
might be possible because biomaterials when developed in the right way have the
potential to domesticate the nature i.e to prevent its detrimental aspect from
taking over an injury while enabling native processes to undertake activity.
IMPORTANCE OF CLINICAL TRANSLATION
PROCESSES
a. Regulatory
and high-valued enhancement.
b. Quality
assurance and control.
c. Increase
in product and industrialization.
d. Domestication
of the nature.
e. The
necessarily help to give accuracy in the implementation processes.
f. Helps
reduce health risk and patient fatality.
g. Boost
or accelerate the growth of pharmaceutical industries.
COMPUTER AIDED DESIGN IN MODELING OF
BIOMATERIALS
Most
research into new biomaterials is based on an experimental trial and error
approach that limits the possibility of making many variation to a single
material and studying its interaction with its surroundings. Instead computer
simulation applied to tissue engineering can offer a more exhaustive approach
to test and screen out materials. It is observed that study of finite element
in tissue engineering is additional to its finite modeling which shows the
usefulness of computer simulation in determining the mechanical environment of
cells which seeded into a scaffold and the proper design of the geometry and
stiffness of the scaffold.
ADVANTAGES AND DISADVANTAGES OF
MODELING PROCESSES
The
advantages includes:
i.
Extensive instrumentation is not required.
ii.
Complex larger problems can be split into
smaller problems.
iii.
It is completely non-invasive procedures.
iv.
3-dimensional models can be generated.
v.
Actual physical properties can be simulated
and external environment also simulated.
vi.
The operator can repeat the study as many
times as possible.
The
disadvantages includes:
i.
This rigidity in the elemental nodal complex
can result in errors.
ii.
To simulate physical environment, certain
assumptions are made which can result to errors.
iii.
The properties assigned for calculations are
not satisfactory.
CONTRIBUTIONS TO THE INDUSTRIAL SECTOR
From
2009 to 2013, the VIT’s industrialization of biomaterials have developed
technologies, utilizing basic skills in different perspective like
biotechnology, process technology, material science, modeling and analytics.
The technologies developed through the program held between 2009 to 2013 has
stirred to generate value chains stretching from forest biomass to selected
high volume consumers product without disputing the fragile value chain of the
food sector. This has also played a big role industrially by integrating the
new value chain into existing bio-refineries (popmils, bio-fuels producers,
breweries, and cereals side streams).
ECONOMIC IMPORTANCE OF COMPUTER AIDED
MODELING PROCESS IN HUMAN LIVES
In recent years, advances in computer
aided designs and computer aided manufacturing has provided new possibilities
in dental practices, however before 3D printing can be implanted, its accuracy
and reproducibility should be evaluated, the human health have been in serious
danger when there was no introduction of the computer aided modeling process in
biomaterials, but their introduction has helped saved lives trough implantation
of useful biomaterials.
CONCLUSION
Biomaterials play an immense role in
tissue engineering, human lives and are generally prepared from various
available natural/synthetic polymers or from inorganic sources. The question of
cyto-compactibility, bio availability, bio degradability, and stability in
terms of mechanical and thermal has not been satisfied by any of the biomaterials
available till date. Each biomaterial has its own drawbacks and bringing the
high value and functionality to the material to satisfy the current need of
tissue engineering is a challenging risk.
The stability of biomaterials is
achieved with the use of stabilizing/cross linking agent in the case of natural
polymers glutaraldehyde which has been generally employed.
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B. Park, Biomaterials Science and Engineering, Plenum Press, New York, 1984.
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Stark and G. Agarwal (eds.), Biomaterials, Planum Press, New York, 1969.
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G. Webster (ed.) Encyclopedia of Medical Devices and Instrumentation, J Wiley
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F. Williams and R. Roaf, Implants in Surgery, W. B. Saunders Co., Philadelphia,
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The
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