Interaction of polynucleotides with cultured mammalian cells. II. Cell surface charge density and RNA uptake

Ionic liquids: prospects for nucleic acid handling and delivery

Operations with nucleic acids are among the main means of studying the mechanisms of gene function and developing novel methods of molecular medicine and gene therapy. These endeavours usually imply the necessity of nucleic acid storage and delivery into eukaryotic cells. In spite of diversity of the existing dedicated techniques, all of them have their limitations. Thus, a recent notion of using ionic liquids in manipulations of nucleic acids has been attracting significant attention lately. Due to their unique physicochemical properties, in particular, their micro-structuring impact and tunability, ionic liquids are currently applied as solvents and stabilizing media in chemical synthesis, electrochemistry, biotechnology, and other areas. Here, we review the current knowledge on interactions between nucleic acids and ionic liquids and discuss potential advantages of applying the latter in delivery of the former into eukaryotic cells.

Complex Size and Surface Charge Determine Nucleic Acid Transfer by Fusogenic Liposomes

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.

Dual loading miR-218 mimics and Temozolomide using AuCOOH@FA-CS drug delivery system: promising targeted anti-tumor drug delivery system with sequential release functions

Background

Dual loading drug delivery system with tumor targeting efficacy and sequential release function provides a promising platform for anticancer drug delivery. Herein, we established a novel AuCOOH@FACS nanogel system for co-delivery miR-218 mimics (as bio-drug) and Temozolomide(as chemo-drug).

Methods

DLS and TEM were employed to determine the characteristics of particles and nanogels. The cell viability was calculated for study synergistic effect of both drugs coadministration and in nanogel forms. The amounts of Au uptake were measured by ICP-MS in cell and tumors to quantify the targeting drug delivery efficacy. Tumor weight and mice weight were investigated to study the targeting antitumor efficacy of nanogel system.

Results

The results revealed that using AuCOOH@FACS nanogel as delivery vehicles, drugs could be targeting delivery to tumor site, the intracellular uptake is enhanced to a greater extent, and significant antitumor efficacy is fold increase compared with free drug administration group, without noticeable system cytotoxicity.

Conclusions

This system offers an efficient approach to cancer therapy and holds significant potential to improve the treatment of cancer in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0216-8) contains supplementary material, which is available to authorized users.

Thermodynamic studies and binding mechanisms of cell-penetrating peptides with lipids and glycosaminoglycans

Cell-penetrating peptides (CPPs) traverse the membrane of biological cells at low micromolar concentrations and are able to take various cargo molecules along with. Despite large differences in their chemical structure, CPPs share the structural similarity of a high cationic charge density. This property confers to them the ability to bind electrostatically membrane constituents such as anionic lipids and glycosaminoglycans (GAGs). Controversies exist, however, about the biological response after the interaction of CPPs with such membrane constituents. Present review compares thermodynamic binding studies with conditions of the biological CPP uptake. It becomes evident that CPPs enter biological cells by different and probably competing mechanisms. For example, some amphipathic CPPs traverse pure lipid model membranes at low micromolar concentrations--at least in the absence of cargos. In contrast, no direct translocation at these conditions is observed for non-amphipathic CPPs. Finally, CPPs bind GAGs at low micromolar concentrations with potential consequences for endocytotic pathways.

[Studies on the cytotoxicity of poly-L-arginine, poly-L-lysine and DEAE-dextran in L-cells and mouse embryonic fibroblasts]

Cellular insulin uptake is influenced by poly-L-arginine, poly-L-lysine and DEAE-dextran. In this study it is asked for the mechanisms of these influences as well as for the cytotoxicity of different concentrations of these substances. The experiments aim to contribute to the knowledge on toxic concentrations of polycations.