Polyelectrolyte multilayer-mediated gene delivery for semaphorin signaling pathway control.

The capability of multilayered polyelectrolyte films (MPFs) to control the sequential expression of two genes encoding cell receptors involved in a common cell signalling activity is shown, while achieving a fully functional signal transduction. As a functional model system representative of a cell signalling process that proceeds in a top-down manner, cell collapse induced by semaphorin 3A (Sema3A) was chosen as the target. Polyelectrolyte multilayers were sequentially functionalized with two plasmids encoding Neuropilin-1 (NRP-1) and Plexin-A1 (Plx-A1), respectively, acting as co-receptors for Sema3A.

Sustained delivery of siRNAs targeting viral infection by cell-degradable multilayered polyelectrolyte films.

Gene silencing by RNA interference (RNAi) has been shown to represent a recently discovered approach for the treatment of human diseases, including viral infection. A major limitation for the success of therapeutic strategies based on RNAi has been the delivery and shortlasting action of synthetic RNA. Multilayered polyelectrolyte films (MPFs), consisting of alternate layer-by-layer deposition of polycations and polyanions, have been shown to represent an original approach for the efficient delivery of DNA and proteins to target cells.

Filamentous condensation of DNA induced by pegylated poly-L-lysine and transfection efficiency.

In this paper we propose a detailed analysis of structural and morphological properties of two poly-L-lysine (PLL)-based transfection formulations, PLL/DNA and pegylated PLL (PLL-g-PEG)/DNA, by means of atomic force microscopy (AFM) and transmission electron microscopy (TEM). Comparing PLL-g-PEG/DNA with PLL/DNA polyplexes, we demonstrate that, due to the presence of PEG, the particles differ not only in size, shape, and crystalline structure, but also in transfection efficiency. While PLL condensates DNA in large agglomerates, PLL grafted with polyethylene glycol 2000 can condensate DNA in long filaments with diameters of some nanometers (6-20 nm).