Ferroelectric-specific peptides as building blocks for bioinorganic devices

Summary form only given. Combinatorial phage display methods have been used to identify a circularly constrained heptapeptide sequence, ISLLHST, that strongly associates with a perovskite ferroelectric, lead zirconium titanate, Pb(Zr_xTi_1-x)O₃ (PZT). The affinity and selectively of binding to polycrystalline MOCVD deposited PZT thin films supported on Si/SiO₂/Pt substrates were determined by titering and immunofluorescence microscopy, and the peptide was shown to selectively bind PZT in the presence of Pt, Si, Au, and several different photoresists. Ferroelectric properties were determined by measurement of the P-E hysteresis loop on unmodified and phage bound PZT thin films, and no change in the coercive field, E_c , or the saturation polarization, P_s was observed after contacting the PZT with aqueous buffer or phage binding. Since this preliminary characterization indicates that the PZT is compatible with biological chemistry, work is currently underway to develop a gated nanofluidic device using this chemistry. This is being accomplished by using electron beam lithography to etch nanochannels (~100 nm in width) in photoresists deposited on these PZT substrates. The base of these channels can be modified using the PZT-specific peptide, and by incorporating metallic electrodes into this structure, the charge of the functionalized PZT can be manipulated, forming the basis for such a device