Thermo-and pH-sensitive Polymer with Pendant Spacer-linked Imidazole Cycles

By the reaction of poly(acryloyl chloride) with N-(3-aminopropyl)imidazole, poly(N-(3-(1H-imidazol-1-yl)propyl)acrylamide) was synthesized. The new polymer contains an imidazole ring removed from the main chain by a spacer of five bonds. The structure and purity, molecular weight, hydrodynamic and thermosensitive properties of the obtained sample were studied by1H-and13C-NMR, FTIR spectroscopy, acid-base titration, light scattering, turbidimetry and viscometry. The observed ability of the imidazole-containing polymer to form and destroy associates in water-salt solutions at pH 6.6-7.4 and temperatures of 29-48℃ indicates that these are promising candidates for designing complex biomedical systems. The new polymer is able to form complexes with oligo-DNA more actively than poly(1-vinylimidazole), which is of interest for gene delivery applications. The polymer cross-linked with epichlorohydrin gives micro-relief coatings on the plastic surface, and the modified surface is able to attach negatively charged objects. This thermo-and pH-sensitive polymer modification can be applied to create finely controlled surfaces for cell culturing.

Highly Sensitive Functionalized Conducting Copolypyrrole Film for DNA Sensing and Protein-resistant

In order to exploit the applications ofpolypyrrole （PPy） derivatives in biosensors and bioelectronics, the different immobilization mechanisms of biomolecules onto differently functionalized conducting PPy films are investigated. Pyrrole and pyrrole derivatives with carboxyl and amino groups were copolymerized with ω-（N-pyrrolyl）-octylthiol self-assembled on Au surface by the method of the chemical polymerization to form a layer of the copolymer film, i.e., poly[pyrrole-co-（N-pyrrolyl）-caproic acid] （poly（Py-co-PyCA）） and poly[pyrrole-co-（N-pyrrolyl）-hexylamine] （poly（Py-co-PyHA））, in which the carboxyl groups in poly（Py-co-PyCA） were activated to the ester groups. Based on the structure characteristics, the immobilization/hybridization of DNA molecules on PPy, poly（Py-co-PyCA） and poly（Py-co-PyHA） were surveyed by cyclic voltammograms measurements. For differently functionalized copolymers, the immobilization mechanisms of DNA are various. Besides the electrochemical properties of the composite electrodes of PPy and its copolymers being detected before and after bovine serum albumin （BSA） adsorption, the kinetic process of protein binding was determined by surface plasmon resonance of spectroscopy. Since few BSA molecules could anchor onto the PPy and its copolymers surfaces, it suggests this kind of conducting polymers can be applied as the protein-resistant material.