Biomedical Engineering Reference
In-Depth Information
13.1 OVERVIEW
The currently available approaches for the treatment of organ and tissue loss
include organ transplantation, surgical reconstruction, and implantation of syn-
thetic devices that can perform the functions of the damaged organs. Shortcom-
ings of the aforementioned methods such as donor site morbidity, limited tissue
availability, and immune rejection have led to the development of alternate strat-
egies such as tissue engineering. Tissue engineering strategies generally involve
the use of biodegradable scaffolds as a transient extracellular matrix (ECM), cells
and growth factors to create functional tissue replacements. Biomimetics of the
extracellular matrix involve the development of fi bers that have diameters in the
micrometer to nanometer range to match the collagen fi bers, and glycosamino-
glycans/proteoglycans present in the natural milieu of tissue. Of the various tech-
niques used for the synthesis of micro/nanofi brous scaffolds, electrospinning has
emerged as a simple and robust method. This chapter discusses the different tech-
niques used for the synthesis of electrospun nanofi bers, polymeric materials that
have been used to synthesize nanofi bers using electrospinning, as well as their
applications as scaffolds in musculo-skeletal tissue engineering.
13.2 INTRODUCTION
13.2.1 Rationale for Tissue Engineering
The human body is robust and elegant machinery whose maintenance is a con-
tinuous effort primarily in the form of repair processes. With ageing, the repair
processes reduce and thereby lead to gradual wear of tissue. However, tissue
loss/damage mostly occurs due to other reasons, such as trauma and disease.
Current treatment options for tissue loss include drug therapy, artifi cial implants,
and organ transplantation. Drugs can relieve patients from pain and can poten-
tially help in the healing process. However, the drug treatment is often symptom-
atic and hence temporary, and at best can be used to enhance damaged tissue
repair when tissue loss is not signifi cant. In the event that tissue loss is substantial,
treatment turns to tissue replacement strategies. The current approaches for
organ or tissue replacement include tissue grafting from one site of the patient's
body to another (autograft); from a donor of the same species (allograft), or;
from donor of another species (xenograft) [1,2]. Although these therapeutic
modalities can potentially improve the quality of human life, they are still limited
by certain complications and shortcomings. For example, use of autografts is asso-
ciated with donor site morbidity and limited tissue availability, whereas allografts
pose the risk of disease transfer. Xenografts, though available in suffi cient quanti-
ties, are associated with problems of humoral rejection and transfer of diseases of
animal origin, specifi cally animal viruses [2]. Other strategies involving artifi cial
implants have several shortcomings, such as the potential to evoke adverse
immune response, structural failure over a period of time, and compromised
Search WWH ::
Custom Search