Surface Passivation of Norland Optical Adhesive Improves the Guiding Efficiency of Gliding Microtubules in Microfluidic Devices

The microtubule-kinesin biomolecular motor system, which is vital for cellular function, holds significant promise for nanotechnological applications. <i>In vitro</i> gliding assays have demonstrated the ability to transport microcargo by propelling microtubules across kinesin-coated surfaces. However, the uncontrolled directional motion of microtubules has posed significant challenges, limiting the system's application for precise cargo delivery. Microfluidic devices provide a means to direct microtubule movement through their geometric features. Norland Optical Adhesive (NOA) is valued for its mold-free application in microfluidic device fabrication; however, microtubules often climb up channel walls, limiting controlled movement. In this study, a surface passivation method for NOA is introduced, using polyethylene glycol via a thiol-ene click reaction. This technique significantly improved the directional control and concentration of microtubules within NOA microchannels. This approach presents new possibilities for the precise application of biomolecular motors in nanotechnology, enabling advancements in the design of microfluidic systems for complex biomolecular manipulations.