Stimulus-responsive liposomes as smart nanoplatforms for drug delivery applications

Abstract

Liposomes are known to be promising nanoparticles (NPs) for drug delivery applications. Among different types of self-assembled NPs, liposomes stand out for their non-toxic nature, and their possession of dual hydrophilic-hydrophobic domains. Advantages of liposomes include the ability to solubilize hydrophobic drugs, the ability to incorporate different hydrophilic and lipophilic drugs at the same time, lessening the exposure of host organs to potentially toxic drugs and allowing modification of the surface by a variety of different chemical groups. This modification of the surface, or of the individual constituents, may be used to achieve two important goals. Firstly, ligands for active targeting can be attached that are recognized by cognate receptors over-expressed on the target cells of tissues. Secondly, modification can be used to impart a stimulus-responsive or "smart" character to the liposomes, whereby the cargo is released on demand only when certain internal stimuli (pH, reducing agents, specific enzymes) or external stimuli (light, magnetic field or ultrasound) are present. Here, we review the field of smart liposomes for drug delivery applications.

Liposomes and polymersomes: a comparative review towards cell mimicking

“…Liposomes and polymersomes can be chemically modified (functionalized) to tune their properties, which is particularly important for certain biomedical applications. 15,76,[120][121][122] An important application of small vesicles is drug delivery. 24 To be efficient, such vesicles must achieve two characteristics: delivery of the drugs at the desired site and release of the vesicle content only at that location.…”

“…1,12,19 (a) Biological or chemical stimuli-responsive vesicles pH-Sensitive LUVs and SUVs are the most studied release systems as one can make use of physiological pH-gradients. 122,128,129 Extracellularly, inflammatory tissues and tumors are more acidic than healthy tissues, or intracellularly endosomes and lysosomes also show acidic conditions (below pH 7), making pH change an ideal trigger for drug delivery. 125 pH-Sensitive liposomes are commonly generated using a small amount of anionic lipid derivatives such as N-succinyldioleoylphosphatidylethanolamine (COPE), 130 to an acidic environment, for example below 5.8 (pK a of CHEMS), 133 the negative moiety of these lipids gets protonated switching from vesicles to inverted micelle structures.…”

Exosomes and Exosome-Inspired Vesicles for Targeted Drug Delivery

“…Additionally multi-targeted liposomes have been constructed, which can target two of more receptors simultaneously, with the aim to increase their targeting efficiency [49]. Other approaches employ the use of physical methods as stimuli, to further increase the targeting efficiency of ligand-targeted-liposomes, such as magnetic or ultrasound enhanced targeting [50][51][52]. Nevertheless, in addition to other potential problems, the last multifunctional systems may be perhaps too complicated for translation into drug products, a factor that should also be seriously accounted for when searching for solutions in the problem to realize actively targeted liposomes, or any other type of nanoparticles (NPs).…”

Recent Developments in Graphene and Graphene Oxide: Properties, Synthesis, and Modifications: A Review

“…[6][7][8] When graphene is compared with its roll-shaped counterparts, carbon nanotubes (CNTs), it is worth mentioning that graphene has lower toxicity and superior biocompatibility, simpler methods for production and modification, lower cost, absence of toxic metal contaminants, and a higher specific surface area. [9][10][11][12][13][14][15] To follow up on our previously published review articles covering different areas of nanomaterials and Nanomedicine, [10,12,[16][17][18][19][20][21][22][23][24][25][26][27] the present review covers the structure of graphene and graphene oxide (GO), their properties and synthesis techniques. Different procedures used for modifying the surface properties of graphene and GO through covalent and non-covalent bonding are also discussed.…”