Biomedical Engineering Reference
In-Depth Information
The efficiency of liposomes, as non-viral gene delivery vectors, has been in-
creased through surface ligand targeting via monoclonal antibodies, to specific
receptors upregulated on cancer cell surfaces. A biopolymeric gene deliv-
ery nanoparticle has recently been shown to be effective in vivo, in delaying
tumor growth. This polymeric nanoparticle-based non-viral gene delivery
vector is a cationic albumin-conjugated pegylated nanoparticle, in which
a plasmid, encoding the proapoptotic Apo2 ligand/tumor necrosis factor-
related apoptosis-inducing ligand (Apo2L/TRAIL), is incorporated. After
intravenous injection of plasmid-loaded nanoparticles, plasmid DNA was
incorporated and inhibited tumor growth [89]. Additionally allied tech-
nologies, such as atomization and pressurization, have come in to play to
facilitate the preparation of nanotechnological carriers. One such comprises
a novel method of atomization, namely electrohydrodynamic atomization
used in an electrospraying method. Pressurization techniques such as high
hydrostatic pressure technology for encapsulation of genes into polymeric
nanomaterials have recently been studied for their efficacy in delivering the
biologically active compounds. These novel technologies offer advantages by
eliminating the usage of toxic cationic polymers and chemical tethers, fur-
ther replacing them by simple yet effective hydrogen bonding.
4.3 Nanomedicine and toxicity
Nanotoxicology evaluates the interactions of NPs with biological systems
and the relationship between the physical and chemical properties of NPs
with the induction of toxic biological responses. Currently, a complete evalu-
ation of the size, shape, composition and aggregation-dependent interactions
of NPs with biological systems is lacking, and thus it is unclear whether the
exposure of humans, animals, and plants to engineered nanostructures could
produce harmful biological responses. NPs constitute a part of particulate
matter, and human exposure to NPs has been increased in the past century
because of the industrial revolution. The same characteristics which make
NPs so attractive in medicine, may contribute to the toxicological profile of
NPs in biological systems. NPs own electronic, optical, and magnetic prop-
erties that are related to their physical dimensions, and their breakdown
could lead to a unique toxic effect that is difficult to predict. NPs surfaces
also, are involved in many catalytic and oxidative processes which may be
potentially cytotoxic. Some NPs contain metals or compounds with known
toxicity, and thus the breakdown of these materials could elicit similar toxic
responses to the components themselves. Many people can be exposed to
nanostructures in a variety of methods such as researchers manufacturing
nanostructures, patients injected with nanostructures, or people using prod-
ucts containing nanostructures. Most of the recent studies in this area have
focused on the absorption of the nanostructures via inhalation or dermal
exposure. In the respiratory system NPs activate different transcription fac-
tors with up-regulation of pro-inflammatory protein synthesis. Interestingly,
