Biomedical Engineering Reference
In-Depth Information
capacity and stable structure but also possesses a convenient pH-controlled
loading and release property.
3.3 Functional Mesoporous Silica Nanoparticles with a
Core-Shell Structure for Controllable Drug Delivery
Mesoporous silica nanoparticles have been intensively studied as drug deliv-
ery carriers due to their unique structure and surface properties. However,
pure mesoporous silica suffers from some limitations in many applications
(He and Shi 2011). For example, pure mesoporous silica cannot realize the
targeted drug delivery, and cannot track or evaluate the efficiency of drug
release in disease diagnosis and therapy. Therefore, the combination with
mesoporous silica and functional materials to form the core-shell structure
is a smart strategy to solve the aforementioned limitations, especially to form
magnetic or luminescent mesoporous silica nanoparticles. Thus, these meso-
porous silica nanoparticles with a core-shell structure can be used as multi-
functional platforms for simultaneous targeted drug delivery, fast diagnosis,
and efficient therapy. In this part, we will introduce magnetic, luminescent,
and other multifunctional mesoporous silica nanoparticles with a core-shell
structure for controllable drug delivery.
3.3.1 Magnetic Mesoporous Silica Nanoparticles
for Controllable Drug Delivery
Currently, magnetic nanoparticles, an important class of inorganic materials,
are especially attractive for targeted drug delivery and hyperthermia appli-
cation (Kumar and Mohammad 2011; Laurent et al. 2011). Magnetic targeting
provides the ability to guide the drug delivery systems to the desired location
by means of an external magnetic field and keep them until the therapy is
complete, which will facilitate the therapeutic efficiency and reduce the side
effect of the toxic drugs before targeting the desired positions (Laurent et al.
2011). On the other hand, hyperthermia using superparamagnetic nanopar-
ticles under alternating magnetic fields has been an efficient strategy in can-
cer therapy due to the heating ability of superparamagnetic nanoparticles,
as a result of Brownian rotation and Néel relaxation mechanisms (Kumar
and Mohammad 2011). Among magnetic materials, γ-Fe
2
O
3
and Fe
3
O
4
have
been most intensively studied. However, pure iron oxide is prone to aggre-
gation because of anisotropic dipolar attraction and rapid biodegradation
when they are exposed to biological systems directly (Ruíz-Hernández et al.
2007; Zhou et al. 2007). Furthermore, pure iron oxide nanoparticles as drug
carriers have difficulty anchoring drug molecules and possess relative lower
Search WWH ::
Custom Search