Environmental Engineering Reference
In-Depth Information
Anionic liposomes (AL) complexes with folate (F-AL-Ad5) significantly
improve the gene transduction ability of adenovirus vector Ad5 in airway epithelial
cells which finds importance in delivering therapeutic genes to the airway epithelia
and is promising in clinical medicine. Folate complexation makes F-AL-Ad5 more
potent in gene transduction efficiency than naked AL-Ad5 [
8
]. The spherically
constructed AL into chitosan/DNA (CS/DNA) complexes, AL/CS/DNA
nanoparticles were shown to deliver the anti-caries DNA vaccine pGJA-P/VAX
into nasal mucosa. The pH-dependant surface charge of the AL/CS/DNA enabled
the intracellular release of loaded DNA with higher transfection efficiency and
longer residence time at nasal mucosal surface. An AL/CS/DNA unique structural
feature helps to significantly induce higher level of secretory IgA imposing a long
term mucosal immunity and minimal cytotoxicity thereby enabling efficient elici-
tation of mucosal immunity mediated by improved DNA vaccine packaging and
delivery nanoliposomes [
2
,
9
].
Liposomes can fuse with hydrophilic particles thereby generating simple vectors
of nanomedicine. Anionic silica particle fused with a cationic lipid (DOTAP) on a
loading anionic fluorescent dye (calcein) could be efficiently taken up and released
by Chinese hamster ovary cells under reduced pH condition [
10
].
Removal of salt has been reported to increase the efficiency of liposomes. Salt-
free cationic and anionic (catanionic) lamellar vesicles made of tetra-decyl-
trimethyl ammonium hydroxide and lauric acid reveal a much higher saturation
binding with DNA thus implying high transfection efficiency while retaining its
native stretched state during the interaction process. These catanionic vesicles are
of great relevance in gene delivery of undisturbed and extended DNA molecules
into the target cells [
11
].
pH sensitization of liposomes generates efficient liposomes as compared to
pH insensitive liposomes. pH-sensitive liposomes composed of cholesteryl
hemisuccinate (CHEMS) and DOPE revealed greater transfection efficiency of
the pDNA as compared to pH insensitive ones [
12
].
Cationic lipid-based liposomes (CLP) can easily complex with negatively
charged nucleic acids by electrostatic interactions, resulting in nanocarriers with
biocompatibility, low toxicity, and easy large-scale production required for in vivo
clinical trials. CLP-DNA complexes (lipoplexes) used for the delivery of plasmid
DNA was modulated with the use of targeting ligands like epidermal growth factor
and transferrin. They can target cancer cells over-expressing the receptors for these
ligands specially [
13
].
The characteristics of liposomes (i.e., encapsulation efficacy, zeta potential, size,
membrane fluidity, aggregation in serum, and uptake) with different surface poten-
tials vary based on the enhanced permeation and retention (EPR) effect [
14
].
Neutral liposomes (NLP) like DOX-loaded NLPs and polyethylene glycol
(PEG)-modified NLPs (NLP-PEG) preferentially localized in solid tumors whereas
CLP like PEGylated CLPs (CLP-PEG) has a propensity for localizing in newly
formed tumor vessels. In the presence of serum, cationic lipids help in liposome
