Biotinylated Polythiophene Copolymer - A Novel Electroactive Biomaterial Utilizing the Biotin-Streptavidin Interaction

Abstract : A novel hierarchical biomaterial capable of incorporating any biotinylated biomolecule has been created. Our strategy is to biotinylate one- dimensional electroactive polymers and use a bridging streptavidin protein on Langmuir-Blodgett (LB) organized films. The following copolymeric system which enables functionalization of other molecules and formation of good monolayers was employed. Biotinvlated poly(3-methanolthiophene-co-3-undecylthiophene (B- PMUT) demonstrated a significantly better isotherm implying superior molecular packing compared to poly(3-methanol thiophene-co-3-undecyl thiophene) (PMUT) on the LB air-water surface. The isotherm showed significant area expansion when streptavidin was injected below the B-PMUT monolayer in 0.1 mM NaH2PO4/0-1 M NaCl buffer (ph 6.8) subphase. We then incorporated biotinylated phycoerythrin (B-PE) into this novel biomaterial by binding the unoccupied biotin binding sites on the bound streptavidin (4 sites total). The pressure-area isotherm of the protein injected monolayer showed area expansion. A characteristic fluorescent emission peak at 576 nm was detected from the monolayer transferred onto a solid substrate. These observations demonstrated the function of B-PMUT in hierarchical monolayer assembly of molecules incorporating the biotin/ streptavidin interaction. Langmuir-Blodgett, Electroactive polymers, Biotin, Streptavidin, Phycoerythrin.