Biomedical Engineering Reference
In-Depth Information
5
Magnetic Nanomaterials for
In Vivo
and
In Vitro
Cancer Diagnostics
Kelly Y. Kim
5.1
Introduction
Magnetic nanoparticles were fi rst introduced as magnetic resonance imaging
(MRI) contrast agents during the late 1980s. Since that time, contrast agents such
as GastroMARK® (ferumoxsil), an oral MRI agent used for gastrointestinal tract
imaging, and Feridex® (ferumoxide), which is also known as ferumoxide, an MRI
agent for the detection of liver lesions, have become commercially available, while
superparamagnetic iron oxides (SPIOs) as MRI contrast agents have also paved
the way for the application of magnetic nanoparticles in current clinical practice.
The surge of interest in nanotechnology during the recent years has signifi cantly
expanded the breadth of research on magnetic nanoparticles. This has led not only
to their utility being optimized for
in vivo
cancer diagnostics, but also to explora-
tions of their application as multifunctional agents, where they serve simultane-
ously as carriers for targeted chemotherapy delivery and as MRI contrast agents
for real-time monitoring of drug distribution to target sites. In addition, they may
be used to follow the effects of therapy on the progression of a disease.
The use of magnetic nanoparticles for
in vivo
diagnostics - that is, for
imaging - has been well established (as noted in Chapter 4); consequently, in this
chapter we will describe the advantages imparted by nanoparticles as compared to
gadolinium (Gd) chelates, which currently are the most widely used MRI contrast
agents. More importantly, multifunctional magnetic nanoparticles are actively
being developed for the monitoring of treatment responses via
in vivo
imaging,
and some of these state-of-the-art advances are described in this chapter.
Today, tremendous progress is also being made on new strategies for incorporat-
ing magnetic nanoparticles into
in vitro
molecular diagnostics. The major goals
for
in vitro
diagnostics are to exploit the unique properties of magnetic nanopar-
ticles to develop assays that are rapid, simple to perform, and cost- effective; and
then to fabricate these assay platforms into devices with nanoscale components
that are portable. From the perspective of point- of - care diagnostics, there is
great interest in developing miniaturized “ lab - on - a - chip ” devices that combine
