Mercedes Perez Mendez - SAXS and SANS investigation of synthetic cholesteric liquid-crystal polymers for biomedical applications

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  Publication Details (including relevant citation   information):


   Journal of Materials Science   and Engineering B 3 (2) (2013)   104-115, M Pérez Méndez and B    Hammouda.



  Multifunctional   cholesteric liquid-crystal polymer, designated   [PTOBEE]10-NH2, has been synthesized, from   precursor PTOBEE   [C26H20O8]n  previously reported, by functionalization with amine groups.   Cholesteric PTOBEE has been shown to be able to entrap DNA, being   tested as non-viral vector in gene therapy, including cationic   monomeric surfactants in their formulation. The direct   interaction between cationic cholesteric liquid-crystal polymer   PTOBEE-NH2, with anionic commercial [Poly-C-Poly-G], is proposed   as new formulation for biomedical applications. The interaction   mechanism is studied in three different volume ratios: (1:2),   (1:1) and (2:1), respectively. Their structures, studied by SAXS   at ESRF, provide information about the complexes size and shape.   Based on preliminary neutron scattering experiments, showing   sufficient contrast (scattering length density difference)   between cholesterol PTOBEE-NH2 (1.5 to1.9 x E+10 /cm2) and   polynucleotide [PolyC-PolyG] (3.32 x E+10/cm2), contrast   variation SANS experiments were performed at NIST, with a   wavelength of λ = 8Å, using different H2O:D2O mixtures (i.e.,   contrasts) to match the cholesterol polymer (44.5%:55.5%), the   polynucleotide (65% or 70%):(35% or 30%) or the whole complex   (30%:70%), being able to “observe separately” both component   structures within the complexes. SANS results agree and   complement the information obtained by SAXS. Different TWO SHELL   molecular models are proposed for the interaction by using a   combination of model-fitting (FISH).

  Address (URL): _j_mat_sci_engin_b.pdf