Optimized dextran–polyethylenimine conjugates are efficient non-viral vectors with reduced cytotoxicity when used in serum containing environments

Abstract

Polyethylenimine (PEI) is a cationic polymer that is an efficient transfection reagent marred by high toxicity and a susceptibility to aggregate in the presence of serum. Dextran is a biodegradable natural polysaccharide that can be used to reduce the toxicity of PEI and increase its stability in the presence of serum. In this study, small branched PEI units (800/2000 Da) were attached to dextran (Dex; 15/100–200 kDa) to form dextran-polyethylenimine (Dex-PEI) conjugates. The Dex-PEI conjugates were then tested as a gene carrier in the model HEK293 cell line. Dex-PEI conjugates displayed significantly lower cytotoxicity than PEI (25k). Both Dex-PEI and PEI efficiently delivered firefly luciferase encoded plasmid DNA (pDNA) to the HEK293 cells. Dex-PEI resulted in moderately lower transfection efficiencies than PEI 25k when the transfection was carried out in media without serum for 4 h. However, in the presence of serum, which more accurately predicts the anticipated environment of non-viral vectors in vivo, Dex-PEI and unmodified PEI generated similar transfection efficiencies when incubated with the cells for 4 h. When the incubation time of the vectors was increased to 48 h, significantly higher transfection efficiencies were generated by Dex-PEI in comparison to PEI. Turbidity measurements showed that complexes formed between plasmid DNA and unmodified PEI were more susceptible to aggregation in serum-containing media than complexes formed from pDNA and Dex-PEI. Dex-PEI conjugates are therefore believed to have greater potential for translational applications because of lower cytotoxicity characteristics and improved stability in serum containing environments.

Spermine-modified Antheraea pernyi silk fibroin as a gene delivery carrier

“…High molecular weight PEI is relatively cytotoxic because of the high density of its cationic groups and its nondegradability. [57][58][59] In this study, CASF/pDNA complexes had a low density of positive charges. The zeta potential of the CASF/pDNA complexes was only approximately +3.0 mV to +3.2 mV, much lower than the +18.0 mV zeta potential of the PEI/pDNA complexes.…”

Micelle-templated dendritic gold nanoparticles for enhanced cellular delivery of siRNA

“…The reduced transfection efficiency of PEI in the presence of serum has been previously reported. [35][36][37] It is conceivable that the unique dendritic structure of Au@MC-2 may play a role in protecting siRNA and stabilizing its complex with Au@MC-2 in the presence of serum, resulting in Cytotoxicity of Au@MC and Au@MC/siRNA. The comparative cytotoxicity of Au@MCs and bPEI 25K was evaluated using the MTT assay.…”

Bone-targeted Novel Cytotoxic Polybisphosphonate Conjugate in Castration-resistant Prostate Cancer: A Multicenter Phase 1 Study

“…with a carbohydrate backbone (dextran). It is well known that conjugation with dextran of potentially toxic compounds decreases toxicity in vivo and increases the therapeutic window (22)(23)(24).…”