Abstract:Lipid-based nanoparticles, also called vesicles or liposomes, can be used as carriers for drugs or many types of biological macromolecules, including DNA and proteins. Efficiency and speed of cargo delivery are especially high for carrier vesicles that fuse with the cellular plasma membrane. This occurs for lipid mixture containing equal amounts of the cationic lipid DOTAP and a neutral lipid with an additional few percents of an aromatic substance. The fusion ability of such particles depends on lipid composi… Show more
“…Applying this method, NA/NR complexes served as cargo and FLs as delivery vehicles. As already clearly shown for FLs in the absence of NR molecules and NAs [34,55], parallel experiments on NA/NR/FL complexes also proved fusion-based transfer and high biocompatibility [38]. Underlying liposomes (there named Fuse-It-mRNA) had the identical composition as characterized here as optimum (DOPE/DOTAP/DiR 1/1/0.1) and were unaffected in effectiveness by various endosomal uptake blockers while keeping natural cell functions of various cell types completely unaffected.…”
Highly efficient, biocompatible, and fast nucleic acid delivery methods are essential for biomedical applications and research. At present, two main strategies are used to this end. In non-viral transfection liposome- or polymer-based formulations are used to transfer cargo into cells via endocytosis, whereas viral carriers enable direct nucleic acid delivery into the cell cytoplasm. Here, we introduce a new generation of liposomes for nucleic acid delivery, which immediately fuse with the cellular plasma membrane upon contact to transfer the functional nucleic acid directly into the cell cytoplasm. For maximum fusion efficiency combined with high cargo transfer, nucleic acids had to be complexed and partially neutralized before incorporation into fusogenic liposomes. Among the various neutralization agents tested, small, linear, and positively charged polymers yielded the best complex properties. Systematic variation of liposomal composition and nucleic acid complexation identified surface charge as well as particle size as essential parameters for cargo-liposome interaction and subsequent fusion induction. Optimized protocols were tested for the efficient transfer of different kinds of nucleic acids like plasmid DNA, messenger RNA, and short-interfering RNA into various mammalian cells in culture and into primary tissues.
“…Applying this method, NA/NR complexes served as cargo and FLs as delivery vehicles. As already clearly shown for FLs in the absence of NR molecules and NAs [34,55], parallel experiments on NA/NR/FL complexes also proved fusion-based transfer and high biocompatibility [38]. Underlying liposomes (there named Fuse-It-mRNA) had the identical composition as characterized here as optimum (DOPE/DOTAP/DiR 1/1/0.1) and were unaffected in effectiveness by various endosomal uptake blockers while keeping natural cell functions of various cell types completely unaffected.…”
Highly efficient, biocompatible, and fast nucleic acid delivery methods are essential for biomedical applications and research. At present, two main strategies are used to this end. In non-viral transfection liposome- or polymer-based formulations are used to transfer cargo into cells via endocytosis, whereas viral carriers enable direct nucleic acid delivery into the cell cytoplasm. Here, we introduce a new generation of liposomes for nucleic acid delivery, which immediately fuse with the cellular plasma membrane upon contact to transfer the functional nucleic acid directly into the cell cytoplasm. For maximum fusion efficiency combined with high cargo transfer, nucleic acids had to be complexed and partially neutralized before incorporation into fusogenic liposomes. Among the various neutralization agents tested, small, linear, and positively charged polymers yielded the best complex properties. Systematic variation of liposomal composition and nucleic acid complexation identified surface charge as well as particle size as essential parameters for cargo-liposome interaction and subsequent fusion induction. Optimized protocols were tested for the efficient transfer of different kinds of nucleic acids like plasmid DNA, messenger RNA, and short-interfering RNA into various mammalian cells in culture and into primary tissues.
“…When CLs surf onto the surface of the cell membrane, cellular uptake may occur through endocytosis or membrane fusion ( Figure 3 ). In contrast, membrane fusion occurs almost exclusively in fusogenic CLs, 95 , 96 which directly translocate their cargo into the cytoplasm, 97 , 98 resulting in efficient drug delivery to the cytoplasm without endosomal entrapment and metabolic degradation. 99 Figure 3 Schematic Diagram of Lipoplexes Entering and Trafficking Within Cells: Entry Pathways and Intracellular Barriers Lipoplexes enter into cells via endocytosis or membrane fusion.…”
Section: Main Textmentioning
confidence: 99%
“… 18 , 146 , 147 , 148 , 149 Kolašinac et al. 95 reported that an inverted conical shape and an aromatic molecule in cationic lipid are indispensable to the fusion induction. Bruininks et al.…”
Section: Main Textmentioning
confidence: 99%
“…Fusogenic lipid, DOPE, is a neutral helper lipid that is commonly added to cationic liposomal formulation for promoting membrane fusion-mediated endosomal escape. 95 , 150 , 151 , 152 , 153 , 154 Meanwhile, as mentioned above, lipoplexes could also enter into the cells via membrane fusion-mediated internalization, which favors the phosphoethanolamine (PE) lipid-enriched lipoplexes. 95 However, the amount of DOPE added to the liposome is controversial and most likely related to the structure and σ M of the cationic lipids.…”
Cationic liposomes (CLs) have been regarded as the most promising gene delivery vectors for decades with the advantages of excellent biodegradability, biocompatibility, and high nucleic acid encapsulation efficiency. However, the clinical use of CLs in cancer gene therapy is limited because of many uncertain factors
in vivo
. Extracellular barriers such as opsonization, rapid clearance by the reticuloendothelial system and poor tumor penetration, and intracellular barriers, including endosomal/lysosomal entrapped network and restricted diffusion to the nucleus, make CLs not the ideal vector for transferring extrinsic genes in the body. However, the obstacles in achieving productive therapeutic effects of nucleic acids can be addressed by tailoring the properties of CLs, which are influenced by lipid compositions and surface modification. This review focuses on the physiological barriers of CLs against cancer gene therapy and the effects of lipid compositions on governing transfection efficiency, and it briefly discusses the impacts of particle size, membrane charge density, and surface modification on the fate of CLs
in vivo
, which may provide guidance for their preclinical studies.
“…For example, in Chinese hamster ovary cells, Kolašinac et al showed that cationic fusogenic liposomes could reach a fusion efficiency ranging from 1 to 92% depending on the cationic lipid composition of the synthetic vesicles [ 52 ]. It is also illustrated that environmental conditions (ionic concentration, pH or buffer osmolality) impact the liposome fusion process which remains very low in physiological conditions [ 53 ]. Although this strategy has shown promise [ 54 ], lack of control over how the molecule is packaged into the vesicle and possible low entrapment of larger cargo may limit its wider applicability.…”
Section: Re-engineering Of the Parental Cellmentioning
Extracellular vesicles (EVs) are emerging as promising nanoscale therapeutics due to their intrinsic role as mediators of intercellular communication, regulating tissue development and homeostasis. The low immunogenicity and natural cell-targeting capabilities of EVs has led to extensive research investigating their potential as novel acellular tools for tissue regeneration or for the diagnosis of pathological conditions. However, the clinical use of EVs has been hindered by issues with yield and heterogeneity. From the modification of parental cells and naturally-derived vesicles to the development of artificial biomimetic nanoparticles or the functionalisation of biomaterials, a multitude of techniques have been employed to augment EVs therapeutic efficacy. This review will explore various engineering strategies that could promote EVs scalability and therapeutic effectiveness beyond their native utility. Herein, we highlight the current state-of-the-art EV-engineering techniques with discussion of opportunities and obstacles for each. This is synthesised into a guide for selecting a suitable strategy to maximise the potential efficacy of EVs as nanoscale therapeutics.
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