Biomedical Engineering Reference
In-Depth Information
6.1 WHAT IS TISSUE ENGINEERING?
Tissue engineering is a biomedical engineering discipline integrating biology with
engineering to create tissues or cellular products outside the body (
)ortousethe
gained knowledge to better manage the repair of tissues within the body (
ex vivo
). This
discipline requires understanding of diverse biological fields, including cell and molecu-
lar biology, physiology and systems integration, stem cell proliferation and differentia-
tion, extracellular matrix chemistry and compounds, and endocrinology. It also requires
knowledge of many engineering fields, including biochemical and mechanical engineer-
ing, polymer sciences, bioreactor design and application, mass transfer analysis of gas
and liquid metabolites, and biomaterials. Translation of tissue engineering constructs to
clinical applications will involve yet other scientific disciplines so novel engineered tis-
sues will be easily accepted and used by clinicians. The combination of these sciences
has spawned the field of
in vivo
which is closely aligned with tissue engi-
neering but has a focus on strategies that use the body's natural regeneration mechanisms
to repair damaged tissues. Two of the main goals of these fields are cell therapies for the
repair of damaged tissues, involving injection or engraftment of cells or cellular suspen-
sions, sometimes in combination with scaffolding material, or establishing tissue ex vivo
for use as grafts or extracorporeal organs to assist or supplement ailing in vivo organs.
Clinical trials with cell therapies or extracorporeally created tissues have begun to be
undertaken in the area of skin, cartilage, bone, heart, neural, and liver tissues, and the first
tissue-engineered products have become available in the last decade. In addition, tissue
engineering strategies are being employed to develop improved in vitro diagnostic and
screening techniques, as well as creating improved tissue models to study disease. Both
scientific and economic issues will define the success of these and future therapeutic
modalities.
regenerative medicine,
6.1.1 The Challenges Facing the Tissue Engineer
Some of the fundamental challenges that face the tissue engineer “in the implementation
of cell therapies or creation of grafts and bioartificial organs” are shown in Figure 6.1.
In particular, the following issues will impact the field as it progresses toward larger-scale
clinical application:
1.
Reconstitution of physical (mass transfer) and biological (soluble and insoluble signals)
microenvironments for the development and control of tissue function.
2.
Overcoming scale-up challenges in order to generate cellular microenvironments on a
clinically and commercially meaningful scale.
3.
Systems automation to provide appropriate process and quality control on clinically
and commercially meaningful scales.
4.
Implementation of tissue engineering technologies in clinical settings, including
appropriate cell handling and preservation procedures that are required for cell
therapies and the transplantation of viable tissues.
