Biomedical Engineering Reference
In-Depth Information
Similarly, platelet-derived growth factor releasing nanospheres immobilized on a phase-separated
nanofibrous scaffold have been shown to promote angiogenesis
[33]
. The temporally and spatially
controlled drug-delivering PLGA nanospheres on the nanofibrous scaffolds can be beneficially
applied to dental and craniofacial tissue regeneration.
24.2.7
Treatment of oral cancer using nanoparticulate drug delivery system
Dendrimer nanoparticles will facilitate drug delivery in the treatment of oral cancer. A single
dendrimer can carry an anticancer drug molecule that recognizes cancer cells, a therapeutic agent
to kill those cells. Dendrimer nanoparticles have shown promise as drug delivery vehicles capable
of targeting tumors with large doses of anticancer drugs. Nanoshells have a core of silica and a
metallic outer layer. By manipulating the thickness of the layer, scientists can design beads to
absorb near infrared light, creating an intense heat that is lethal to cancer cells. The physical
selectivity to cancer lesion site occurs through a phenomenon called enhanced permeation reten-
tion
[25]
. Christoph et al.
[34]
have reported magnetic nanoparticles carrying mitoxantrone for
the treatment of loco-regional cancer treatment in the oral cavity. Bhirde et al.
[35]
have shown
the killing of the cancer cells in vivo and in vitro using epidermal growth factor (EGF) directed
carbon nanotube-based drug delivery; they used anticancer agent cisplatin and EGF which were
attached to single-walled carbon nanotubes (SWCNTs) to specifically target squamous cancer,
and the nontargeted control was SWCNT
cisplatin without EGF. They have proposed the appli-
cation of this approach in oral cancer.
24.3
Toxicity of nanoparticles
In general the toxicity of the nanoparticle drug delivery system can be caused by the drug itself,
the nanoparticles or both. Other terms used for the toxicity of the drug itself are side effects or
adverse drug reactions. The focus of this section is on the toxicity of nanoparticle drug delivery
systems, i.e., the nanoparticles themselves. Four broad mechanisms for the toxicity of nanoparticles
are
[36]
:
1.
Cytotoxicity of one or more of the nanoparticle constituents which is an inherent property of
the chemical compound
2.
Cytotoxicity of one or more of the degradation products of the nanoparticle constituents
3.
Endocytosed nanoparticle-mediated apoptosis (cell death)
4.
Nanoparticle-mediated cell membrane lysis
The nanoparticles are toxic to the cells by mediating cell lysis and/or apoptosis. One important
mechanism for cytotoxicity is oxidative stress mediated by the nanoparticles.
The largest literature for the toxicity of nanoparticles comes from the inhalation toxicity of par-
ticles with a mass of a mean diameter of 10
m
[37]
. Therefore, there is a lot of literature on the
nanoparticle-mediated pulmonary inflammation and tumors in animal models such as rats. Even
though the focus of this chapter section is on the toxicity of nanoparticles from oral drug delivery
μ
