Authors: S. Pabba, B.H. Fasciotto, M.M. Yazdanapanah, V.V. Dobrokhotov, R.W. Cohn
Affilation: University of Louisville, United States
Pages: 673 - 676
Keywords: actin, fibrin, biopolymerization, nanofibers, three dimensional patterning
Many proteins polymerize in vivo to form nanometer diameter fibers, including actin and fibrin. In this study we consider the application of filament-forming proteins to nanostructure fabrication. Specifically, protein fibers are induced to polymerize and form nanometer diameter air-bridges that span tens of microns in length. The orientation of the fibers in three dimensions is driven by a type of directed self-assembly. A protein precursor in buffer solution on the edge of a microscope cover slip is gently brushed by hand over a micromachined array of vertical pillars that are micron diameter. The macroscopic brushing dynamics and the shape of the pillar array direct the assembly of buffered protein solutions into nanostructures. Surface tension, fluid transport, evaporation and polymerization drive the membrane to break up into parallel arrays of fibers connected between two pillars. Arrays of fibrin nanofibers 300 nm diameter and four-point suspended membranes of the appearance of trampolines were formed by brushing a solution of fibrinogen over a pillar array that had been primed with the enzyme thrombin that converts fibrinogen monomers to fibrin monomers which induces polymerization. Air-bridges as narrow as 22 nm and 16 nm were made from fibrin and actin monomer (polymerized by ATP), respectively.