Biomedical Engineering Reference
In-Depth Information
not only be biocompatible but also provide mechanical support for tissue regeneration and thus
polymeric scaffolds need to be further developed and assessed. Presently there are no real solutions
for long-term replacements for some connective tissues, small diameter blood vessels, and nerve
grafts. The clinical need for whole organs is high, and tissue engineering is one emerging fi eld in
regenerative medicine. There still exists need for three-dimensional tissue engineered matrices that
are able to integrate with biological tissues, thereby necessitating the development of more intel-
ligent scaffolds. Controlled and targeted drug delivery is becoming extremely important and there
has been a certain amount of success with many of the technical hurdles to protein delivery being
overcome, particularly as new drugs are developed in tune with delivery systems. The next chal-
lenge is gene delivery, which presents an entirely new set of scientifi c and technical issues, particu-
larly when delivery is to be targeted to a single tissue or cell type in the body and long-term stable
expression is desired. Current gene therapy approaches continue to face problems of immunological
reaction to and low specifi city of viral vectors; thus, synthetic polymer conjugates are exciting alter-
natives. Another important aspect is to establish the immune response to polymer debris. Although
it has been speculated that biodegradable polymers induce infl ammatory reactions because of an
immune response to degradation products and nonreacted monomer compounds, basic mechanisms
need to be further explored. In addition, the advent of the use of nanoparticulate materials and the
effect of such particles from an immunological standpoint needs thorough investigation.
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