Microtubules, which are polymers of a protein called tubulin, are a key component of the cellular cytoskeleton. In vitro, microtubules readily polymerize from tubulin subunits to lengths of 5-20 microns, and are easily functionalized and imaged. These properties make microtubules ideal tools for engineering self-assembling nano-scale systems.
The ability to form self-assembling physical networks on the micro-scale has potential applications in signal transduction. Functionalizing microtubules with metallic particles can potentially create pathways capable of conducting electromagnetic signals.
We use microtubules to form a self-assembling microscale network, using microspheres as nodes, and microtubules as linkers. To achieve this, streptavidin-coated beads were mixed with biotinylated microtubules in a flow cell. The microtubules linked beads up to 30 microns apart (4 times the bead’s radius) and gave rise to networks. A conductive bead-microtubule network provides unique advantages over a static, prefabricated model since the microtubule-bead system can dynamically reorganize in response to stimuli.