Novel dextran–spermine conjugates as transfecting agents: comparing water-soluble and micellar polymers

Abstract

Recently, a novel cationic polymer, dextran-spermine (D-SPM) was developed for gene delivery. An efficient transfection was obtained using this polycation for a variety of genes and cell lines in serum-free or serum-poor medium. However, transfection using the water-soluble D-SPMbased polyplexes decreased with increasing serum concentration in cell culture in a concentration-dependent manner, reaching 95% inhibition at 50% serum in the cell growth medium. In order to overcome this obstacle, oleyl derivatives of D-SPM (which form micelles in aqueous phase) were synthesized at 1, 10, and 20 mol% of oleyl moiety to polymer e-NH 2 to form N-oleyl-D-SPM (ODS). Polyplexes based on ODS transfected well in medium containing 50% serum. Comparison with polyplexes based on well-established polymers (branched and linear polyethyleneimine) and with DOTAP/Cholesterol lipoplexes showed that regarding b-galactosidase transgene expression level and cytotoxicity in tissue culture, the D-SPM and ODS compare well with the above polyplexes and lipoplexes. Intracellular trafficking using FITC-labeled ODS and Rhodamine-labeled pGeneGrip plasmid cloned with hBMP2 monitored by confocal microscopy revealed that during the transfection process the fluorescent-labeled polymer concentrates in the Golgi apparatus and around the nucleus, while the cell cytoplasm was free of fluorescent particles, suggesting that the polyplexes move in the cell toward the nucleus by vesicular transport through the cytoplasm and not by a random diffusion. We found that the plasmids penetrate the cell nucleus without the polymer. Preliminary results in zebra fish and mice demonstrate the potential of ODS to serve as an efficient nonviral vector for in vivo transfection. Gene Therapy (2005) 12, 494-503.

RETRACTED ARTICLE: Engineered Polyallylamine Nanoparticles for Efficient In Vitro Transfection

“…In spite of having well spaced primary amino groups, the low proton affinity of PAA is well documented and the polymer is predicted to exist like micelles in aqueous solutions with separate hydrophobic and hydrophilic domains (31). Moreover, micelle forming lipoamines have been shown to be more efficacious in gene delivery (32). The properties of PAA can be well utilized for designing the transfection agents, as primary amino groups can be readily substituted chemically by various groups.…”

Characterization and in vivo performance of dextran–spermine polyplexes and DOTAP/cholesterol lipoplexes administered locally and systemically

“…However, until recently [18] no side by side comparison of polyplexes and lipoplexes was done. Such comparison is important for a better understanding of the transfection process, as these two systems differ extensively in many of their basic physicochemical properties, which (as shown in this study) are relevant for the efficacy of transfection.…”

“…This study was dedicated to meet this objective. We compared lipoplexes based on the mixture of the monocationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and the neutral helper lipid cholesterol [4], and our novel (but well characterized) polyplexes based on the cationic polymer dextran-spermine (D-SPM) [14][15][16][17][18]. Although these two systems have some similarities, such as being able to self-assemble with DNA and form large assemblies upon interaction with negatively charged serum proteins, they differ to a large extent in most of their other physicochemical properties.…”

Effects of CXCR4 siRNA/dextran-spermine nanoparticles on CXCR4 expression and serum LDH levels in a mouse model of colorectal cancer metastasis to the liver

“…They reported dextran-spermine being the least cytotoxic. 14,15 In this experiment, dextran-spermine was not toxic at 15 µg/mL by MTS and CXCR4 siRNAs at 3000 ng/mL. With respect to the low ratio of 1:5 and low doses of siRNAs used to make the nanoparticles, small size of nanoparticles 57.62 nm ± 2.51 with high zeta potential 39.8 mV ± 0.2.…”