Introduction - Microsurgery: Advances, Simulations, and Applications - page 25

tissue engineering-based ( in vitro ) regeneration are introduced by
using representative examples. An artiicial organ is a man-made
structure that is implanted into, or integrated onto, human body to
replace in damaged organs a natural function or a group of related
functions. This enables the person receiving the artiicial organ to
stay alive or continue a normal life [69].
Materials for long-term implantable devices and their
applications were listed by David Williams [117], as well as some
of the generic host response to biomaterials. Titanium alloys are
used for dental implants, femoral stems, pacemaker cans, heart
valves, fracture plates, and spinal cages. Cobalt-chromium alloys
are used for bearing surfaces, heart valves, stents, and pacemaker
leads. Platinum group alloys are used for electrodes. Nitinol is used
for shape memory alloys applications. Stainless steel is used for
stents and orthopedic implants. Alumina and UHMW are used for
bearing surfaces. Calcium phosphates are used for bioactive surfaces
and bone substitutes. Carbon is used for heart valves. PEEK is used
for spinal cages. PMMA is used as bone cement and for intraocular
lenses. Silicones are used for tissue augmentation, lead insulation
and ophthalmological devices. Polyurethane is used for pacemaker
lead insulation. Expanded PTFE and polyester textile are used for
heart valves and vascular grafts. Poly(styrene-block-isobutylene-
block-styrene) is used for drug eluting stent coating. Some of the
responses listed by Williams are: protein absorption and desorption
characteristics, generalized cytotoxic effects, neutrophil activation,
macrophage activation, ibroblasts behavior, microvascular changes,
tissue or organ speciic cell response, activation of clotting cascade,
platelets adhesion, activation and aggregation, complement
activation, antibody production and immune cells responses,
acute hypersensitivity and anaphylaxis, mutagenetic response and
genotoxicity, reproductive toxicity, and tumor formation.
1.3.1 Artificial Organs
1.3.1.1 Artificial heart
Cardiac diseases are one of the three major causes of death. The main
purpose of artiicial heart is to replace the function of left ventricle.
From 1935, development of artiicial heart has been continued to
mimic real heart as much as possible. Initially, researchers made
exertion mainly on mimicking the shape of heart. However, the point