Chemical transfection reagents

In this volume, we have brought together articles from various experts in the chemical transfection reagent field. Topics covered include descriptions of the chemistry of chemical transfection compounds and details of the fundamental parameters that influence transfection efficiencies. 

Several authors describe distinct classes of chemical transfection reagents. Fischer et al. summarize synthesis methods, features, and applications of hyper-branched polyamines as carriers for nucleic acids. 

Fig. 1 (a) Synthesis of dextran-spermine conjugates, (b) Fluorescence micrographs of dextran-spermine compared to common transfection reagents in HEK293 and NIH3T3 cells. Adapted with permission from [38]. 2002 American Chemical Society... 

While several reviews collected in this volume describe the basic chemical composition of transfection reagent classes, Salcher and Wagner focus on the modification and functionalization of polymeric gene carriers to improve their transfection efficiencies for DNA or siRNA. Such modifications include the introduction of cell-specific ligands or pH-sensitive lytic residues. 

Both mechanical means and transfection reagents, among others, have been used to facilitate the cellular uptake of oligonucleotides. The application of intraluminal pressure enhances the uptake of particular oligonucleotides in vascular tissues such as carotid arteries or venous bypass grafts [14, 15]. Other approaches use chemical modifications in order to secondarily modify the nucleic acid backbone [16, 17]. In general, these modifications increase uptake through the cell membrane based on the classical receptor-mediated endocytosis pathway. However, once inside the cell, most nucleic acid compounds taken up by endocytosis are ultimately trapped in the lysosomal compartment... 

Besides nonspecihc cellular effects due to the RNAi compounds themselves, there are additional sources for potential nonspecihc effects these include the vehicles for, and methods of, delivery of RNAi compounds to cells and tissues. For example, viral vectors, as well as other components such as transfection reagents [136], chemical modihcations to RNAi compounds, or chemical substances used to facilitate the delivery of RNAi compounds, might produce unwanted immune and other cellular responses [137]. These responses should be considered as additional possible sources for nonspecihc effects in therapeutic applications of RNAi. 

Currently, a linear ultrapure PEI (molecular mass 22 g/mol) is commercially available as a transfection reagent. However, at least in our hands, such a preparation was not superior to the branched bulk PEI ordered from a standard supplier of chemicals (25 g/mol PEI from Aldrich Chemical Company Inc., Milwaukee, USA). 

A polyamidoamine dendrimer-capped mesoporous silica nanosphere-based gene transfection reagent. Journal of the American Chemical Society, 126(41), 13215-17. 

Chemical methods include a variety of popular DNA/RNA delivery techniques. DNA mixed with DEAE-dextran which is a polycationic derivative of dextran, a carbohydrate polymer that associates readily with the negatively charged nucleic acids, was one of the first reagents to be used for transient transfection. An excess of positive charge, contributed by the polymer allows the complex to come into closer association with the plasma membrane (8). This method is simple and inexpensive, but is low in efficiency, in part due to... 

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