Biomedical Engineering Reference
In-Depth Information
Stainless steel was i rst used successfully as an implant material in the sur-
gical i eld; this success was accomplished when aseptic surgery was estab-
lished. h en, vitallium, a Co-based growing alloy, was put into practical
use. Titanium is the newest metallic biomaterial among the three main
metallic biomaterials and these remain the most popular of the metallic
alloys. Titanium and its alloys have excellent biocompatibility, light weight,
excellent balance of mechanical properties, excellent corrosion resistance,
etc. [58, 59]. Nowadays, large number of metallic biomaterials composed
of nontoxic and allergy-free elements are being developed [60, 61].
2.5.4
Ceramic Materials for Biomedical Devices
Bioceramics are special compositions of ceramic materials in the form
of powders, coatings, or bulk devices, used widely to repair, augment or
replace diseased or damaged tissues, usually bones, joints or teeth. Clinical
use of bioceramics is rapidly expanding because of the increasing rate of
failure of metallic or polymeric devices (also called prostheses or implants).
Although many compositions of ceramics have been tested for medical
use, very few compositions are used clinically. A1
2
O
3
and ZrO
2
, have been
used primarily in total joint replacement. Calcium-phosphates are used as
coatings on metal alloys or as particles or porous shapes for bone repair.
Bioactive glasses and glass-ceramics are employed in the replacement of
ear bones, teeth or vertebrae or as powders to repair bone [62, 63].
2.5.5
Sol-gel Materials for Biomaterials Devices
Sol-gel technology is a wonderful advancement in science and requires a
multidisciplinary approach for its various applications. It has been used for
the fabrication of optical i bers, optical coatings, electro-optic materials,
nanocrystalline semiconductor-doped xerogels, colloidal silica powders
for chromatographic stationary phase and as catalytic support [64, 65].
Applications utilizing sol-gel as a porous material to encapsulate sensor
molecules, enzymes and many other compounds are most common; how-
ever, some potential applications of sol-gel-derived materials in biomedical
applications are fast emerging. Biomedical applications require the design
of new biomaterials and this can be achieved by merging sol-gel chemis-
try and biochemistry. Gel-derived materials are excellent model systems
for studying and controlling biochemical interactions within constrained
matrices with enhanced bioactivity because of their residual hydroxyl ions,
micro-pores and large specii c surface [66].
