A challenge for nanotechnology is the dynamic control of nanomachines from the outside world. We are pursuing a biomimetic solution, where activating molecules are delivered to a user-defined target. Specifically, we aim to deliver ATP, which activates the kinesin motor proteins powering our "molecular shuttle" transport system [1,2], with high spatial and temporal resolution.
Previously , we demonstrated temporal control of kinesin motor activation by photolysing "caged ATP" using pulses of UV light, which results in the release of ATP. Rapid sequestration of the released ATP by an additional ATP consuming enzyme led to the stepwise movement of the molecular shuttles.
Here we present the extension of this control strategy to the spatial domain, aiming at the controlled activation of individual shuttles. By combining patterned illumination with carefully designed enzymatic ATP sequestration, we create plumes of ATP in the vicinity of the biomolecular motors. The boundaries of these ATP plumes are defined by steep gradients in space and time, overcoming the challenges posed by the rapid diffusion of ATP.
Enzymatic networks, such as the combination of a motor enzyme using ATP as fuel with an ATP-sequestering enzyme, are a natural solution to the controlled activation of nanodevices, and our work represents a first application in nanobiotechnology.
Figure caption: A molecular shuttle system is envisioned to load, transport, sort, and assemble nanoscale building blocks (top). A hybrid design approach, combining synthetic environments and biomolecular motors, utilizes surface-bound kinesin motor proteins to transport functionalized microtubules along fabricated tracks. Reproduced with permission from Nano Letters 2003, 3, 1651-1655. Copyright 2003 Am. Chem. Soc..
1. Hess H, Vogel V: Molecular shuttles based on motor proteins: Active transport in synthetic environments. Reviews in Molecular Biotechnology 2001, 82:67-85.
2. Hess H, Bachand GD, Vogel V: Powering Nanodevices with Biomolecular Motors. Chemistry - A European Journal 2004, 10:2110-2116.
3. Hess H, Clemmens J, Qin D, Howard J, Vogel V: Light-Controlled Molecular Shuttles Made from Motor Proteins Carrying Cargo on Engineered Surfaces. Nano Letters 2001, 1:235-239.