Biomedical Engineering Reference
In-Depth Information
14
Bone tissue engineering
M. Santin, University of Brighton, UK
Abstract
: in the last three decades, tissue engineering has emerged as a
new discipline with the aim of addressing serious clinical cases where the
spontaneous repair of damaged tissue is impaired. Bone tissue engineering
is one of the most investigated areas of application and a large body of
data is now available that sheds light on the ideal features of a bone tissue
engineering construct. Materials scientists are now able to synthesise
biomimetic and bioresponsive biomaterials that fulfil the main requirements
for tissue formation
in vitro
or
in vivo
. Biodegradable/bioresorbable
polymers, ceramics and composites have been developed which can act as
substrates for the adhesion of cells and for the deposition of the calcium
phosphate mineral phase of the bony tissues. When engineered into three-
dimensional (3D) scaffolds able to host cells (progenitor or differentiated)
and bioactive molecules (growth factors, genes and drugs), these
biomaterials can constitute an ideal environment to foster the formation
of new tissue and to integrate it into the host environment. although
preliminary clinical studies have shown the great potential of bone tissue
engineering, the constructs employed still lack an integrated approach
where clinical needs are met by a careful design of the construct in all its
components and growing conditions. These unmet clinical needs require a
coordinated response by scientists, industrialists and policy makers.
Key words
: biomaterial engineering, biomaterial scaffolds, bone diseases,
bone repair, bone trauma, cell seeding, tissue engineering.
14.1 Introduction
the long clinical history of biomedical implants clearly shows that, while
reducing patients' mortality and improving their life quality, they are not
able to completely restore the physiology of the damaged tissue. Based on
polymeric, metallic and ceramic biomaterials, these implants exert their role,
either by replacing the structure and biomechanics of the damaged tissue
or by providing a scaffold for its regrowth. in the case of non-degradable
biomaterials, the best clinical performance is achieved when good tissue
integration is reached. However, the non-degradable biomaterials which are
usually employed for the manufacture of permanent devices do not allow the
implant to participate in the later remodelling that characterises any tissue.
Conversely, bioresorbable/biodegradable biomaterials offer the opportunity of
achieving complete tissue repair, their gradual degradation being accompanied
by formation of new tissue. However, unless growth factors or drugs are added
to their formulation, this class of biomaterials supports new tissue formation
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