Approaches for hybrid biological and synthetic system integration

Eukaryotic cells use cytoskeletal tracks known as microtubules and motor proteins such as kinesin for transporting intracellular cargo and for positioning organelles. Kinesin motors move unidirectionally along microtubules using the energy from hydrolysis of adenosine triphosphate (ATP). Studies have shown that the forces generated by the kinesin motors are sufficient to mobilize synthetic devices. A critical component in realizing useful work from the directional motion of biomolecular motor protein systems involves patterning kinesin motors in pre-defined areas and aligning microtubules on various surfaces. In order to reduce another degree of freedom in such systems both kinesin and microtubules need to be patterned simultaneously. Traditional device fabrication processes such as lithography, however, are not considered compatible with the biological proteins. Accordingly in previous studies devices were fabricated first and functional proteins immobilized on them subsequently. To create hybrid biological and synthetic systems it may be necessary to integrate biological entities such as proteins with device fabrication processes. Toward this end, a series of experiments were conducted to investigate the compatibility of neutravidin and biotinylated kinesin with acetone, remover of electron beam resist poly methyl methacrylate (PMMA). It is found that neutravidin and biotinylated kinesin retain their functionality after acetone exposure. It is also found that exposure to PMMA does not defunctionalize. These studies open up a new approach for the micro and nanoscale patterning of biological molecular motors.