Novel polymeric materials via reactive polymers

Abstract

Novel synthetic strategies for fabrication of reactive polymers, multifunctional hydrogels and bio-functionalizable micro-patterned hydrogels are described. A set of highly efficient chemical reactions referred as ‘click’ reactions are utilized. In conjunction with novel crosslinking strategies, various lithographic techniques during the fabrication enable the creation of micro-patterned hydrogels. In the first study, a novel N-hydroxy succinimide based carbonate monomer is designed to yield amine-reactive polymers that provide stable, yet hydrolysable carbamate-based conjugations. As the second study, novel functionalizable crosslinked hydrogels are obtained utilizing thiol-epoxy chemistry. Gelation of epoxide terminated telechelic polymers via thiol-epoxy reaction yields nearly well-defined functionalizable hydrogels. As an alternative, hydrogels were fabricated via photo-polymerization using PEG-based triblock copolymers containing glycidyl and PEG-methacrylate side chains in their outer blocks. These hydrogels can be further functionalized using epoxide ring-opening reactions. In the third project, thiol-reactive patterned polymeric platforms are obtained via nanoimprint lithography. Sub-micron patterned reactive materials that are stable through non-covalent crosslinking are fabricated. The thiol-reactive micro-patterned surfaces enable successful immobilization of dyes, peptides as well as cells. The fourth project describes fabrication of thiol-reactive maleimide-containing hydrogels using thiol-ene crosslinking. Furan-protected maleimide-containing triblock copolymers along with dithiol-based crosslinkers provide hydrogels via the radical thiol-ene reaction. Thermal activation of residual masked maleimides provides hydrogels that are functionalized with thiol-containing dyes and ligands that enable protein immobilization. In the last study, photo-dimerization of maleimide units in the side chains of copolymers is utilized for the synthesis of hydrogels without employing cross-linkers and photo-initiators. Residual maleimides are efficiently functionalized using the Michael conjugation or Diels-Alder. In summary, multifunctional polymeric platforms in soluble forms, as well as bulk and micro-patterned crosslinked hydrogels are designed. Efficient multi-funtionalization of these materials could be achieved using the reactive handles installed during the fabrication of polymeric materials.