Biomedical Engineering Reference
In-Depth Information
biomolecules via proper conjugation chemistry, which provides a
surpassing edge in developing new nanocarriers for gene therapy.
Among several types of metallic NPs, gold NPs (AuNPs) have been
widely adopted as a nucleic acid delivery system due to their low
toxicity and the ease of modification of surface properties such
as charge and hydrophobicity.
55, 56
Several functional ligands
and biomolecules can be attached onto the surfaces of the AuNPs
through strong chemisorption of thiol groups, and furthermore
these biomolecules can be released from the particles through the
reductive intracellular environment.
57
Quantum dots (QDs) are semiconductor NPs and have
significant advantages over the traditional organic dyes, including
enhanced stability and minimal photobleaching.
24
These QDs,
therefore, have been utilized in biological applications such as
imaging, labeling, detection
58-62
and also have been used as add-ons
to the other nanocarrier systems due to their relatively small sizes,
typically between 2 to 12 nm.
63, 64
However, the surface of QDs can
be modified with several functional components, including nucleic
acid via conjugation, and such features allow QDs to be useful as
nanocarriers for gene delivery.
Magnetic NPs (MNPs) have also been used in nucleic acid
delivery because of their unique magnetic properties that allow
them to be utilized as a diagnostic tool (primarily in magnetic
resonance imaging, MRI) and as targetable nanocarriers for gene
therapy. This combination of imaging and targeted therapy is known
as “theranostics.”
65
Among several other materials, including cobalt
or nickel, iron oxide has been widely used for a NP core because of
its low toxicity profile. The iron oxide core is usually coated with
biocompatible materials (e.g., polysaccharide, synthetic polymer,
lipid, protein, etc.) to provide stability in physiological conditions
and the opportunity for further modification with macromolecular
biotherapeutics. Although the adoption of MNPs in drug delivery
system is a relatively new approach, there have been several studies
that reported successful delivery of siRNA to cancer cells in mice
with an improved plasma pharmacokinetic profile and therapeutic
effects.66,
66, 67
Silica has been investigated as a potential candidate for
nanocarriers of nucleic acid because of its natural biocompatibility
and low toxicity and its ease of modification and functionalization
onto the silanol surface of NPs.
68-70
In particular, mesoporous silica
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