This NSF-funded research project is being performed within the UNC Nanoscale Science Research Group.

Summary: The growth of technology in our every day lives has been driven by the dramatic, exponential decrease in the size of computing circuitry over the last three decades. This has given rise to unimagined applications of microprocessors throughout almost every manufactured item around us. A similar revolution is beginning in systems that extend beyond electrical signals and include actuating components (MicroElectroMechanical Systems-MEMS) and chemical synthesis and analysis. It can be expected that the miniaturization of these complex systems will benefit widespread applications as well, perhaps including implantable components that incorporate sensing, synthesis and delivery of pharmacological agents, or smart materials that can alter their own chemistry and hence physical properties. In developing nanometer scale systems, we are inevitably faced with the problem of actuation and transport, as well as the need to power these functions and couple them to electronic circuitry. Nature has already provided remarkable solutions to parts of this problem, supplying us with molecular motors that would fit into a box 40 nm on a side and are powered chemically by individual ATP molecules. This project is studying the control over molecular motors with an engineering applications perspective, exploring ways in which these incredible machines can be used in designed systems.

This project aims to: 1) demonstrate controlled patterning of motor raceways as functioning tracks for the motion of motor proteins, 2) study the two of the main classes of proteins actin/myosin and microtubule/kinesin to understand their relative merits towards nanotechnology applications, 3) study the application of single motors and collections of motor proteins, 4) study the coupling of nanotubes to electrical circuitry through electro/dielectrokinesis at the nanometer scale, and 5) understand a processing methodology for incorporating nanometer scale ebeam lithography, nanotube placement/growth, patterned chemical functionalization and motor binding and motility. These capabilities and fundamental characterizations will be applied to new force sensing analyzing devices and multiplexing arrays. This research program will closely couple nanoscale engineering with the basic science of motor proteins.

Processing: Controlled Patterning of Biomotor Motion

• Pattern through nanometer-scale definition of surface chemistry (AFM or ebeam lithography)
  
• Pattern deposition of motors (myosin/kinesin) and filaments (actin/microtubules)
  
• Control deposition through patterning of electric potential (Electrochemistry/Dielectrophoresis)
  
• Attachment of motors/filaments to nanotubes of varying surface chemistry
  
• Chemically stabilize filaments for increased operational robustness/lifetime
  
• Define a processing strategy for integrated nanoscale metal, nanotube and biomotor patterning.

Control over Motor motion as Transportation Systems:

• Individual motors and collective properties of multiple motors
• Electrostatic control of motion (stalling, steering, reversing loads as carried by multiple motors)
• Local strain, temperature effects

Large Effects from Nanoscale systems: Biomotors/Nanotube Devices

• In-situ sensing of motor motion
• Integration in analyzing system and multiplexing/sorting array

This effort builds on the expertise of the UNC Nanoscale Science Research Group in nanometer scale devices and nanotubes, as well as experience in biological scanning probe microscopy imaging. We are creating nanometer scale devices from ebeam lithography and atomic force microscopy manipulation, including the incorporation of carbon nanotubes. The biomolecular motors are being incorporated into these devices through the patterned deposition of the substrates in registry with the electronic devices. Motility assay and measures of the control over motor function will use optical microscopy and optical tweezers, and a combination AFM/optical microscope system.

Education and training: This research effort is being peformed in collaboration with the UNC NIH Center for Computer-Integrated Systems for Microscopy and Manipulation, a highly interdisciplinary group of students, postdocs and professors from Computer Science, Physics, Chemistry, Library Science and Material Science meeting weekly. This proposal will bring biology students directly into the center of this community. This project is the first bio-nanotechnology project of this kind at UNC. Most important, it is beginning the development of new training for graduate students who go outside of traditional curricula to master their projects.