In Vitro Gene Delivery by Degraded Polyamidoamine Dendrimers

Abstract

Transfection of cultured cells has been reported using complexes between DNA and spherical cationic polyamidoamine polymers (Starburst dendrimers) that consist of primary amines on the surface and tertiary amines in the interior. The transfection activity of the dendrimers is dramatically enhanced (> 50-fold) by heat treatment in a variety of solvolytic solvents, e.g., water or butanol. Such treatment induces significant degradation of the dendrimer at the amide linkage, resulting in a heterodisperse population of compounds with molecular weights ranging from the very low (< 1500 Da) to several tens of kilodaltons. The compound facilitating transfection is the high molecular weight component of the degraded product and is denoted as a "fractured" dendrimer. Transfection activity is related both to the initial size of the dendrimer and its degree of degradation. Fractured dendrimers exhibit an increased apparent volume change as measured by an increase in the reduced viscosity upon protonation of the terminal amines as pH is reduced from 10.5 to 7.2 whereas intact dendrimers do not. Dendrimers with defective branching have been synthesized and also have improved transfection activity compared to that of the intact dendrimers. For a series of heat-treated dendrimers we observe a correlation between transfection activity and the degree of flexibility, computed with a random cleavage simulation of the degradation process. We suggest that the increased transfection after the heating process is principally due to the increase in flexibility that enables the fractured dendrimer to be compact when complexed with DNA and swell when released from DNA.

Transgene expression is increased by photochemically mediated transduction of polycation-complexed adenoviruses

“…The SuperFectt reagent consists of activated polyamidoamine dendrimers with a spherical architecture. 27 Charged amino groups at each branches radiating from the central core can interact with negatively charged molecules.…”

CL22 – a novel cationic peptide for efficient transfection of mammalian cells

“…Nonviral transfection agents reported in the literature include polydisperse cationic polymers such as polylysine, 4,5 defined length oligolysines, 6,7 polyarginine, 8 polyethyleneimine, [9][10][11][12] Starburst dendrimers 13,14 or cationic lipids. [15][16][17] Although many of ants that define some properties of the peptide that contribute to efficient transfection.…”

Highly efficient suicide gene expression in hepatocellular carcinoma cells by Epstein-Barr virus-based plasmid vectors combined with polyamidoamine dendrimer

“…With regard to the gene delivery vehicles, a number of methods have been devised, including those using liposomes, synthetic polymers, and physical means such as electroporation and a gene gun. [2][3][4][5][6] Despite the recent progress in these techniques, the transfection/expression efficiency of nonviral systems remains relatively poor as long as conventional plasmid vectors are used. Less effort has been made to improve plasmid vectors, although some novel promoter/enhancers are being actively investigated.…”