Ammonium Gemini Surfactants Form Complexes with Model Oligomers of siRNA and dsDNA

Abstract

Dimeric cationic surfactants (gemini-type) are a group of amphiphilic compounds with potential use in gene therapy as effective carriers for nucleic acid transfection (i.e., siRNA, DNA, and plasmid DNA). Our studies have shown the formation of lipoplexes composed of alkanediyl-α,ω-bis[(oxymethyl)dimethyldodecylammonium] chlorides and selected 21-base-pair nucleic acid (dsDNA and siRNA) oligomers. To examine the structure and physicochemical properties of these systems, optical microscopy, circular dichroism spectroscopy (CD), small-angle X-ray scattering of synchrotron radiation (SR-SAXS), and agarose gel electrophoresis (AGE) were used. The lengths of spacer groups of the studied surfactants had a significant influence on the surfactants’ complexing properties. The lowest charge ratio (p/n) at which stable lipoplexes were observed was 1.5 and the most frequently occurring microstructure of these lipoplexes were cubic and micellar phases for dsDNA and siRNA, respectively. The cytotoxicity tests on HeLa cells indicated the non-toxic concentration of surfactants to be at approximately 10 µM. The dicationic gemini surfactants studied form complexes with siRNA and dsDNA oligomers; however, the complexation process is more effective towards siRNA. Therefore these systems could be applied as transfection systems for therapeutic nucleic acids.

The Process of Binding and Releasing of Genetic Material from Lipoplexes Based on Trimeric Surfactants and Phospholipids

“…The downside of polymeric surfactants is increased toxic effects. Trimeric surfactants studied in this work are characterized by higher cytotoxicity than dimeric surfactants of similar composition already described in [ 15 , 17 ]. The EC 50 value (the concentration at which 50% of the cells died) for TRI_N surfactant was assessed as 15 ± 3 μM whereas its dimeric analogue was characterized by almost three times higher value (42.2 ± 0.2 μM) [ 15 ].…”

“…Trimeric surfactants studied in this work are characterized by higher cytotoxicity than dimeric surfactants of similar composition already described in [ 15 , 17 ]. The EC 50 value (the concentration at which 50% of the cells died) for TRI_N surfactant was assessed as 15 ± 3 μM whereas its dimeric analogue was characterized by almost three times higher value (42.2 ± 0.2 μM) [ 15 ]. For TRI_IMI surfactant EC 50 = 24 ± 6 μM, and for its closest dimeric counterpart, this parameter was determined as 42.02 μM [ 17 ].…”

“…In our research to date, we have focused mainly on the use of dicationic surfactants to create stable and nontoxic lipoplexes with nucleic acids, both siRNA oligomers and long and short DNA fragments [ 12 , 15 , 16 ], also including surfactants with amino acids molecules (glycine) as counter ions [ 17 ].…”

Lactose-based surfactants complexable with oligonucleic acids as gene delivery agents

“…The dsDNA sequence was chosen to be identical to the sequence of siRNA. We had already successfully used these two sequences for testing the carriers of nucleic acids based on gemini surfactants [16][17][18][19][20]. The short sequence of single-stranded DNA (23 nucleotides) was designed as a reference for potential studies on transfection efficiency [21,22].…”

Tetraethylenepentamine-Coated β Cyclodextrin Nanoparticles for Dual DNA and siRNA Delivery

“…Cationic polysaccharides can bind with siRNAs to form complexes, thereby protecting siRNA from degradation and neutralizing their negative charges [ 19 ]. Nanoparticles formed with cationic BCD and siRNA demonstrated efficacy not only in knocking down genes of interest in mice [ 20 ], but were able to inhibit tumor growth in a mouse model of metastatic Ewing’s sarcoma [ 21 ].…”