Dendrimers fractured

This increase has two-fold implications. First, it implies that the fractured dendrimer is more flexible than the intact dendrimer and second, that the fractured dendrimer may expand due to an increase in positive charge at lower pH, a quantity that was described as essential for PEI mediated transfection. Indeed, when branched PEI was subjected to the same set of experiments, the same three-fold increase in viscosity was observed, lending support to the idea that PAMAM dendrimers act as proton sponges. Evidence of lysosomal buffering capability of PAMAM dendrimers was shown by Kukowska-Latallo et al. (1996) when they observed that the efficiency of G5-EDA dendrimers was enhanced by the addition of chloroquine, while the same molecule could not enhance transfection of G10-EDA dendrimers, which contain 40-fold more surface amine groups for proton absorption. 

S. I. Stupp reported studies on dendrimers for gel formation in bone fissures which have possible applications in the treatment of bone fractures [74]. 

Rudolph C, Lausier J, Naundorf S, Muller RH, Rosenecker J. In vivo gene delivery to the lung using polyethylenimine and fractured polyamidoamine dendrimers. J Gene Med 2000, 2, 269-278. 

Interestingly, one of the most well-known transfection reagents of genetic material into eukaryotic cells is SuperFect , which is based on amine-terminated PAMAM dendrimers. Moreover, it has been shown that more flexible fractured PAMAM dendrimers exhibited better DNA or RNA transfection properties compared with non-fractured dendrimers. To achieve higher transfection efficiencies, recent design studies have focused on dendrimer structures incorporating higher flexibility (e.g. softer dendrimers). ... 

The effect of 5th generation polyamidoamine (PAMAM G5) dendrimers on multilamellar dipalmitoylphosphocholine (DPPC) vesicles was investigated. PAMAM was added in 2 different concentrations to the lipids (10 and 10 dendrimer/lipid molar ratios). The thermal behavior of the evolved systems was characterized by DSC while the structure and the morphology were investigated with small- and wide-angle X-ray scattering (SWAXS), freeze-fracture electron microscopy (FFTEM) and P NMR spectroscopy, respectively. The obtained results show that the dendrimers added in 10 molar ratio to the lipids generate minor perturbations in the multilamellar structure and thermal character of... 

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