Electric-Field-Enhanced Self-Assembly of .alpha.-helical polypeptides

Electrolyte-Dependent Multiparticle Motion near Electrodes in Oscillating Electric Fields

“…Electrolytes, prepared using ultrapure water (Barnstead, 18.2 MΩ), contained type I collagen monomers (final concentration 0.07 -0.30 mg/mL from 3 mg/mL Vitrogen stock solution, Inamed Biomaterials) and sufficient NaOH and HCl solutions (EMD chemicals, ACS reagent grade) to adjust the pH to the desired value (4)(5)(6)(7)(8)(9)(10)(11). Stainless steel sheet electrodes provided an electric field of 5-10 V over 1.0-2.5 cm, yielding a current density of -0.7 to -1.2 mA/cm 2 .…”

A Helical Molecule That Exhibits Two Lengths in Response to an Applied Potential

“…Because both helix types display a large dipole moment along the helical axis, [22] it is expected that the polarity of the applied voltage between the STM tip and the gold substrate influences the STM image of the peptides. [23,24] BL12S was observed by STM under application of the positive sample bias as described above. When the sample bias was inverted from positive to negative, the bright spots of BL12S disappeared within a few scans, but they reappeared with a return to the positive bias (Figure 4 a).…”

Electrochemically Controlled Growth and Positioning of Suspended Collagen Membranes

“…2 However, many in vitro collagen films are substrate supported 2-5 which limits their use as membranes. Our results demonstrate that two independently recognized in vitro polymer aggregation variables, electric field [6][7][8][9][10] and pH, 1,11,12 can be used in concert to form suspended collagen network films, without the presence of a supporting substrate. This approach could benefit lab-on-a-chip technologies 13 for rational placement of ion separation membranes in microfluidic devices.…”