Nanotechnology Now

After reading the article Fantastic voyage: Tiny pharmacies propelled through the body could result from Cornell breakthrough in molecular motors [Cornell News Sept. 7, 1999], I became curious as to progress in this area. Accordingly, I emailed Dr. Bachand at Sandia National Labs, to find out more about the work that he and Carlo Montemagno performed while at Cornell.

I'd be happy to give you an overview on the progress of our work with the ATPase biological motors. The news release that you referred to represented some of our early work with the F1-ATPase bio-motor. We initially were evaluating the potential for this motor to power nanomechanical devices. We attached polystyrene microspheres to the rotor (gamma subunit of F1-ATPase) and determined some of the biophysical attributes of rotation during ATPase hydrolysis. Using this data, we were able to engineer a proof-of-principle system, and successfully demonstrate that these ATPase motors could power simple nanomechanical devices in synthetic systems. That work was published in Science (see references below), with a follow-up paper in Biomedical Microdevices that discusses the engineering issues that were addressed in constructing this device. We also published a paper detailing precision attachment of F1-ATPase motors on nanofabricated substrates.

I left Prof. Montemagno's group in January 2001 for a position at Sandia National Labs. I am still working with biological motors; different motors in a slightly different context. We are interested in using biological motors and other associated active biomolecules to engineer materials that have selected properties that mimic those found in living systems (e.g., dynamic reconfiguration of nanoscale materials).

When I left Prof. Montemagno's group, the ATPase research was addressing two important aspects to further developing this technology. First, we were engineering a biochemical mechanism for controlling the motor's activity (i.e., an on/off switch for the motor). The details of this work are currently being reviewed for publication in Science. The second aspect involved developing a system to recycle ATP using light energy. In order to continuously provide fuel for ATPase-powered devices, we incorporated bacteriorhodopsin and FoF1-ATPase molecules into liposomes and demonstrated the ability to use light to produce ATP (i.e., ADP + Pi to ATP). Prof. Montemagno left Cornell for UCLA in October 2001, and in the Mechanical and Aerospace Engineering Department.

And here are his answers to my followup questions:

We are interested in mimicking Nature's ability to actively assemble, reconfigure, and disassemble nanoscale materials and structures. As an example, we are interested in mimicking the mechanism by which organisms such as chameleons change color. This involves rearrangement of pigmented nanoparticles by linear translation using biological motors.

Nanoscale features and structures currently are fabricated by lithographic or passive, self-assembly processes. In contrast, living organisms utilize active, non-equilibrium processes to assemble, reconfigure, and disassemble structures. These processes are the driving forces behind cellular functions such as cell division, chromosomal segregation, replication, self-healing, etc. Our overall goal is developing new materials that would possess some of the processes and functions.

We currently have isolated a robust kinesin motor from a thermophilic fungus, and are working toward characterizing the biochemical and biophysical properties of the enzyme. These enzymes function as Nature's solution to the limitations associated with diffusion (i.e., kinesin motors active transport molecular cargo within cells). We are also working toward engineering control mechanisms into the system that will permit use to turn the motor on/off and regulate cargo loading/unloading in integrated nanosystems.

The most difficult technical challenge centers on the interface between biological and non-biological components. Integration of active biomolecules with micro-fluidic and mechanical systems requires the ability to successfully interface the different components without affecting the structure or function of each component. Therefore a major effort concerns exploring the interfacial properties of the components, and engineering the components based on these properties.

The practical applications of this work are very speculative and futuristic at this time. However, it is easy to imagine that engineering materials that have the ability to reconfigure, self-repair, or function as "smart materials" will have a wide variety of applications in many different contexts.

Our work involves much more than a single motor; rather it involves a number of active biomolecules and associated micro- and nanoscale synthetic components. I think that the time frame for any type of commercialization would be at least 25 years in the future. However, the concepts and principles that we are addressing may have short-range impacts in commercial production of materials.

BIO:

George D. Bachand is a staff member in the Biomolecular Materials and Interfaces Division at Sandia National Laboratories. Prior to coming to Sandia, he was a research faculty member in the Department of Agricultural and Biological Engineering at Cornell University. At Cornell, he was responsible for coordinating and conducting research on the integration of biological motors as nanoscale actuators in synthetic, engineered systems. His primary research interest involves the synthesis, genetic engineering, manipulation, and integration of biomolecules as structural and function components of nanomaterials. Current research activities include genetic engineering of protein coding sequences, development of integration mechanisms for biomolecules at synthetic interfaces, and integration of active, bio-sensitive films with microfluidic detection and separation devices. George received his Ph.D. in Environmental and Forest Biology from the State University of New York, Syracuse in 1997.

Publications:

• 1.) Bachand GD, Montemagno CD. 2000. Constructing organic/inorganic NEMS devices powered by biomolecular motors. Biomedical Microdevices 2:179-184.
• 2.) Bachand GD, Soong RK, Neves HP, Olkhovets A, Craighead HG, Montemagno CD. 2001. Precision attachment of individual F1-ATPase biomolecular motors on nanofabricated substrates. Nano Letters 1(1):42-44.
• 3.) Montemagno CD, Bachand GD. 1999. Constructing nanomechanical devices powered by biomolecular motors. Nanotechnology 10:225-331.
• 4.) Soong RK, Bachand GD, Neves HP, Olkhovets AG, Craighead HG, Montemagno CD. 2000. Powering an inorganic nanodevice with a biomolecular motor. Science 290(5496):1555-1558.
• 5.) Soong RK, Neves HP, Schmidt J, Bachand GD, Montemagno CD. 2001. Engineering issues in the fabrication of a hybrid nano-propeller system powered by F1-ATPase. Biomedical Microdevices 3(1):71-73.

Dr. Bachand's contribution reprinted with permission. Copyright George Bachand, Sandia National Laboratories, and Nanotechnology Now.