envelope to allow increased chances of interaction with host genome and, hence,
increased success of gene integration.
– NPs are relatively easier to make, less expensive and more stable during longterm storage. Furthermore, they can be tested for the absence of endotoxins and
other harmful ingredients and, therefore, are safe to use.
– Because NPs can be synthesized chemically, free of animal-derived
components, they are ideal for use when absence of animal-derived components
is a priority, for example, in biopharmaceutical applications. Absence of animalderived components may also facilitate regulatory compliance.
– The absence of lipids in non-lipid-based NPs makes them suitable in lipid or
signal transduction research.
– In the field of transgenesis, NP-mediated gene delivery might be useful in
species for which conventional methods of gene delivery are not effective
(e.g. chicken).
3 Types of NPs Used for In Vitro Gene Delivery into Cells
3.1 Inorganic NPs
3.1.1 Metal and Metal-Based NPs
Gold (Au) and silver (Ag) NPs are the two most frequently commercialized NPs
for variety of uses. Of the two, AuNPs have been at the forefront of metal NP
research investigating gene delivery applications, owing to their well-established
surface chemistry and physico-chemical properties. AuNPs are biocompatible,
nontoxic and are relatively easy to synthesize in a range of sizes by simple, cheap
and reliable methods. DNA loading and release from AuNPs are governed, for the
most part, by hydrogen bonding and Au-thiol chemistry [9–11]. Consequently,
gene delivery using AuNPs has been well demonstrated by several researchers
[12, 13]. AgNPs were, however, found to have cytotoxic and genotoxic potential
in mammalian cells such as human mesenchymal stem cells (MSCs) [14] and,
hence, are not normally used.
Several authors have also functionalized AuNPs for controlling the manner, place
and timing of DNA release. When AuNPs were functionalized with polyethyleneglycol–orthopyridyl-disulfide (PEG–OPSS), the loaded DNA could be released from
the AuNPs by laser irradiation at a power density value of 80 mJ/pulse without any
fragmentation of DNA [15]. Chen et al. [16] attached thiol-modified DNA to the
surface of Au nanorods through Au–S bonds. When femtosecond NIR irradiation
was applied to the Au nanorod–DNA conjugates, a change of shape from rod to
sphere was observed, which induced the release of DNA. A similar phenomenon
was described by Takahashi et al. [17]. Wijaya et al. [18] further showed that Au
nanorods can be used to selectively release multiple DNA. Electroporation is yet
56
P. Pushp et al.
increased success of gene integration.
– NPs are relatively easier to make, less expensive and more stable during longterm storage. Furthermore, they can be tested for the absence of endotoxins and
other harmful ingredients and, therefore, are safe to use.
– Because NPs can be synthesized chemically, free of animal-derived
components, they are ideal for use when absence of animal-derived components
is a priority, for example, in biopharmaceutical applications. Absence of animalderived components may also facilitate regulatory compliance.
– The absence of lipids in non-lipid-based NPs makes them suitable in lipid or
signal transduction research.
– In the field of transgenesis, NP-mediated gene delivery might be useful in
species for which conventional methods of gene delivery are not effective
(e.g. chicken).
3 Types of NPs Used for In Vitro Gene Delivery into Cells
3.1 Inorganic NPs
3.1.1 Metal and Metal-Based NPs
Gold (Au) and silver (Ag) NPs are the two most frequently commercialized NPs
for variety of uses. Of the two, AuNPs have been at the forefront of metal NP
research investigating gene delivery applications, owing to their well-established
surface chemistry and physico-chemical properties. AuNPs are biocompatible,
nontoxic and are relatively easy to synthesize in a range of sizes by simple, cheap
and reliable methods. DNA loading and release from AuNPs are governed, for the
most part, by hydrogen bonding and Au-thiol chemistry [9–11]. Consequently,
gene delivery using AuNPs has been well demonstrated by several researchers
[12, 13]. AgNPs were, however, found to have cytotoxic and genotoxic potential
in mammalian cells such as human mesenchymal stem cells (MSCs) [14] and,
hence, are not normally used.
Several authors have also functionalized AuNPs for controlling the manner, place
and timing of DNA release. When AuNPs were functionalized with polyethyleneglycol–orthopyridyl-disulfide (PEG–OPSS), the loaded DNA could be released from
the AuNPs by laser irradiation at a power density value of 80 mJ/pulse without any
fragmentation of DNA [15]. Chen et al. [16] attached thiol-modified DNA to the
surface of Au nanorods through Au–S bonds. When femtosecond NIR irradiation
was applied to the Au nanorod–DNA conjugates, a change of shape from rod to
sphere was observed, which induced the release of DNA. A similar phenomenon
was described by Takahashi et al. [17]. Wijaya et al. [18] further showed that Au
nanorods can be used to selectively release multiple DNA. Electroporation is yet
56
P. Pushp et al.