Materials Science & Engineering

Biography

Biography: Mercedes Pérez Méndez

Abstract

Cholesteric Liquid Crystal Polymers (ChLCP), synthetized in our laboratory through a stereoselective polycondensation reaction, as multifunctional optically active materials, have been extensively characterized by NMR, Raman spectroscopy, steady-state fluorescence, molecular modeling, and SAXS/WAXS. These ChLCP behave both as thermotropic and lyotropic, confering interesting macromolecular properties indicative of potential application on the biomedical and engineering field. The amphiphilic nature of their monomers makes them polymerize along helical chains, being able to entrap smaller molecules inside, such as Lycopene. They have shown to be biocompatible against macrophages and fibroblasts cellular lines, and able to interact with biomacromolecules such as lipids (both neutral and cationic) and nucleic acids, the structures of the complexes being identified by synchrotron radiation source. Cationic liposomial/surfactant systems based on our CLCP were developed which entrapped DNA plasmids, acting as non viral cationic vectors for gene therapy, which successfully transfected in several tumor cell lines. Cationic functionalized ChLCP have been synthesized, dispersed in TAE and directly complexed with commercial DNA of increasing complexity: [Poly-A]; [Poly-C]; [Poly-G]; [PolydT]; [PolyC-PolyG]; [PolyAC-PolydT]; commercial calf thymus DNA and plasmid. Three different proportions ChLCP:DNA were prepared: (1:2), (1:1), and (2:1) respectively by mixing and digesting for 12h in a swinging shaker. The structure of the cationic complexes has been studied by SAXS at the BM16 beamline at ESRF, at room temperature . Neutron scattering experiments, had shown sufficient contrast (scattering length density difference) between new cholesteric PTOBEE-Ammonium (1.5 to 1.9x1010/cm2) and polynucleotide [PolyC-PolyG] (3.32x1010/cm2) for contrast variation SANS experiments. This experiment was successfully performed at NIST.