Design,synthesis and evaluation of spermine-based pH-sensitive amphiphilic gene delivery systems: Multifunctional non-viral gene carriers

Design and development of efficient non-viral gene delivery systems is critical to overcome various barriers for effective intracellular gene delivery.Eight new spermine-based protonatable surfactants were designed,synthesized and evaluated as non-viral pH-sensitive gene carriers.These carriers formed stable complexes with plasmid DNA at an N/P ratio as low as 2.The sizes of the carrier/pDNA nanoparticles (N/P = 12) were in the range of 90–130 nm,smaller than that of Lipofectamine2000/pDNA nanoparticles.The...     

Kinetic and mechanistic studies of the thermal stabilization of polyacrylamide by metal ions

The kinetics of thermal decomposition of polyacrylamide under a nitrogen atmosphere are studied in the presence of adsorbed metal ions using rising temperature thermogravimetry. Results are analysed using the method of Coates and Redfern¹⁵ and indicate that all of the metal ions, except Tl(I), Hg(I) and Ni(II), stabilize the polymer against degradation. Attempts are made to correlate both initial and total activation energies for degradation with various parameters, including reciprocal ionic radii, ionization potentials, electronegativity and ligand field stabilization energy, to obtain a better understanding of the mechanism of stabilization. The best correlations are between the total activation energy and either reciprocal ionic radii, or the Kahwa-Mulokozi function involving covalent and ionic radii, and ionization potentials. It is suggested that both covalent and ionic interactions in the polymer-metal ion complexes may be important in the stabilization.