Biomedical Engineering Reference
In-Depth Information
8
The Use of Magnetic Particles in Tissue Engineering
Sarah H. Cartmell and Jon Dobson
8.1
Introduction
Magnetic microparticles and nanoparticles, primarily iron oxides, have been used
in biomedical applications such as tissue engineering [1], cell separation/immu-
noassay, drug targeting and delivery, gene delivery and transfection, and as mag-
netic resonance imaging (MRI) contrast agents [2-4]. These particles often consist
of a magnetic iron oxide core coated with a biocompatible polymer that can be
functionalized in order to attach binding molecules such as antibodies, peptides,
and other functional groups [5, 6].
More recently, magnetic nanoparticles have been used increasingly for tissue
engineering applications. Tissue engineering has been described as “... an inter-
disciplinary fi eld that applies the principles of engineering and life sciences toward
the development of biological substitutes that restore, maintain, or improve tissue
function or a whole organ” [7]. In many cases, the objective is to seed a patient's
own cells onto a porous, biodegradable scaffold, and then to coax the cells to
produce the required tissue matrix as the scaffold decays. Ultimately, all that
remains is the new tissue construct ready for implantation into the site of the
defect. By using the patient's own cells, the problem of immunorejection is over-
come, although in practice this is proving diffi cult to achieve. By utilizing the
benefi ts of magnetic particles as “mechanotransducers”, it is possible to control
cellular behavior in a remote fashion, to infl uence the three - dimensional ( 3 - D )
structure, and aid in the formation of functional tissue constructs [8]. In this
chapter, we will review the progress of these approaches in tissue engineering as
applied to various tissue types.
8.1.1
Mechanotransduction
By attaching magnetic nanoparticles to functional sites, both on the cell membrane
and on internal cellular components, the particles can act as transducers of applied
