Microtubule Motors in Microfluidics

Kinesin motor proteins carry out a range of transport functions in eukaryotic cells including long-distance transport in neurons and the movement of chromosomes during cell division. Because emerging microfluidic devices utilize channel geometries similar to cellular scales and because these devices generally require transport through these channels, there is significant interest in incorporating biomotor-driven transport into microfluidic devices. Kinesin-driven transport has the advantage of being able to work against concentration gradients and bulk fluid flow, and microtubules can be functionalized to carry a range of cargo. This chapter describes the foundational methods for generating kinesin-driven transport in engineered microchannels. Protocols are described for expressing and purifying recombinant kinesin, purifying and fluorescently labeling bovine brain tubulin, and carrying out the microtubule gliding assay. General design considerations are presented for integrating kinesins and microtubules into microchannels, followed by a detailed description of a microfluidic device prototype that successfully integrates microtubule-based transport.