The Role of Formamidine Groups in Dextran Based Nonviral Vectors for Gene Delivery on Their Physicochemical and Biological Characteristics

Abstract

Dextran‐formamidine esters (dextran‐N‐[(dimethylamino)methylene]‐β‐alanine ester) with different degrees of substitution (0.45–0.92) are synthesized in an one‐pot reaction. Dextran (Mw 60 000 g mol−1) is allowed to react with unprotected beta‐alanine and iminium chloride and investigated regarding the potential as gene delivery system for the transfer of plasmid DNA. With degrees of substitution ≥ 0.63 improved DNA binding with formation of enzymatically stable complexes of about 130–160 nm with negative surface charges are obtained. These physicochemical characteristics correlated with increasing transfection rates in CHO‐K1 cells determined by a luciferase reporter gene assay in dependency of the number of formamidine residues, N/P ratios and amount of DNA. The role of the number of formamidine groups is also highlighted by in vitro cyto‐ and hemotoxicity tests under the chosen conditions. These results indicate that dextran‐formamidine esters are a very promising material for the safe and efficient gene delivery.

Dually Modified Cellulose as a Non-Viral Vector for the Delivery and Uptake of HDAC3 siRNA

“…Compared to other cationic-modified polysaccharides [ 50 , 51 ], the obtained polymer shows stronger effects on the cell viability and a lower IC 50 value. In order to address concerns regarding biocompatibility, the corresponding N/P ratios were, therefore, also tested for their effect on the endothelial barrier.…”

“…After HMEC-1 reached a steady-state resistance (Figure 9B), the cells were stimulated with free HDAC3 siRNA, polymer, or polyplexes of the displayed N/P ratios (Figure 9), and the measurement was continued for 72 h. Compared to other cationic-modified polysaccharides [50,51], the obtained polymer shows stronger effects on the cell viability and a lower IC 50 value. In order to address concerns regarding biocompatibility, the corresponding N/P ratios were, therefore, also tested for their effect on the endothelial barrier.…”

A synthesis of [14C]formamidine acetate

“…In the morning, the collected product crystals were filtered and washed with 3 Â 20 ml portions of cold diethyl ether. The solid was then dried under high vacuum, affording 0.819 g (7.87 mmol, 426.3 mCi, 71% radiochemical yield) of [ 14 C] formamidine acetate (3). The specific activity of 3 was measured gravimetrically to be 54.2 mCi/mmol, and it was found to be 98% radiochemically pure by TLC (Avicel ® developed with butanol-acetic acid-water [60:15:20], R f 0.45) and co-chromatographed with authentic formamidine acetate (Sigma-Aldrich F15803).…”

“…As a functional group, formamidine has also been a critical structural feature in substances as diverse as insecticides 2 and pharmaceuticals. 3 When labeled with carbon-14, formamidine has served as a valuable precursor to obtain more complicated radiolabeled compounds, 4 and we now disclose a convenient synthesis of it.…”