Search

A series of ionic complexes with a comb-like architecture and a nearly stoichiometric composition were prepared from bacterial poly(gamma,dl-glutamic acid) (PGGA) and alkyltrimethyl phosphonium bromides (nATMP·Br) bearing long linear alkyl chains with even numbers of carbon atoms (n) ranging from 12 to 22. The nATMP·PGGA complexes were non-water soluble but readily soluble in organic solvents, and they displayed a high thermal stability. Combined DSC and XRD studies revealed that these complexes adopted an amphiphilic layered structure with the polypeptide chain and the alkyl chain separated in two differentiated phases with a nanoperiodicity that increased steadily with the length of the alkyl chain. The paraffinic phase was found to be partially crystallized in an extent that decreased with n, so that complexes with n = 12 and 14 did not show any sign of crystallinity whereas those with n from 16 to 22 showed crystalline melting in the ~30–70 °C range. The structural transitions taking place by temperature effects were characterized by simultaneous SAXS/WAXS using synchrotron radiation at real time. In all cases, a shortening of the layer periodicity occurred upon heating with recovering of the initial structure after cooling. nATMP·PGGA with n = 16 showed strong antimicrobial activity against both E. coli and S. aureus, a property that could be related to the weak dissociation of the complexes happening upon incubation in water. The structure and properties of these complexes where comparatively discussed taking as reference their analog complexes made from PGGA and alkyltrimethylammonium bromides already studied by us.

Various specially designed poly(N-isopropylacrylamide-co-acrylic acid) (NIPA-co-AAc) nanogels (NGs) with different NIPA/AAc molar composition were synthesized by precipitation/dispersion polymerization and evaluated as carriers for drug delivery systems (DDSs) of doxorubicin hydrochloride (DOXOHCl) for cancer therapies. The NGs presented excellent dispersability in physiological environments (pH 7.4 and 5 at 37 C), as shown by dynamic light scattering (DLS). Moreover, the NGs exhibited high drug loading capacity and efficiency due to the ionic interaction of the cationic drug with the anionic NGs. NGDOXO HCl formulation presented excellent dispersability in water and minimal leakageof the cargo at plasma simulated medium (pH 7.4 and 0.14 M NaCl) at 37 C and a triggered release at lysosomal simulated medium (pH 5 and 0.14 M NaCl). This release behavior together with their size and the low cytotoxicity determined by the MTT assay converts these NGs in great candidates for their application as carriers in cancer therapies based on the enhanced permeability and retention effect (EPR) with drug pH-triggered release after endocytosis in tumor cells. Fil: Cuggino, Julio César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Molina, Maria. Freie Universität Berlin. Institut für Chemie und Biochemie; Alemania Fil: Wedepohl, Stefanie. Freie Universität Berlin. Institut für Chemie und Biochemie; Alemania Fil: Alvarez Igarzabal, Cecilia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Calderon, Marcelo. Freie Universität Berlin. Institut für Chemie und Biochemie; Alemania Fil: Gugliotta, Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina

The ionic Pd(II)-complexes of 2 (ammonium-[1-(2-hydroxyethyl)-3-methylimidazolium] bis[3-(diphenylphosphino)benzenesulfonate]-dichloropalladium(II) ([(NH4)(Hemim)][PdCl2(TPPMS)2])) and 3 (bis[1-n-butyl-3-methylimidazolium] bis[3-(diphenylphosphino)benzenesulfonate]-dichloropalladium(II) ([Bmim]2[PdCl2(TPPMS)2])) were synthesized and fully characterized. The single crystal X-ray diffraction analyses show that 2 and 3 are composed of the imidazolium-based cations and [PdCl2(TPPMS)2]2 − anions. The properties of such imidazolium-based Pd-complexes of 2 and 3, in terms of the aqueous solubilities and the catalytic behaviors in water, could be dramatically varied. When 2 and 3 were applied as the precatalysts for the Sonogashira coupling of iodobenzene with phenylacetylene under aerobic and CuI-free conditions, the much higher yields of 1,2-diphenylethyne were obtained due to their amphiphilicity. The wide generality of 2 was available for aqueous–organic biphasic Sonogashira reactions.