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

The\nmicrotubule-kinesin biomolecular motor system, which is vital\nfor cellular function, holds significant promise for nanotechnological\napplications. <i>In vitro</i> gliding assays have demonstrated\nthe ability to transport microcargo by propelling microtubules across\nkinesin-coated surfaces. However, the uncontrolled directional motion\nof microtubules has posed significant challenges, limiting the system’s\napplication for precise cargo delivery. Microfluidic devices provide\na means to direct microtubule movement through their geometric features.\nNorland Optical Adhesive (NOA) is valued for its mold-free application\nin microfluidic device fabrication; however, microtubules often climb\nup channel walls, limiting controlled movement. In this study, a surface\npassivation method for NOA is introduced, using polyethylene glycol\nvia a thiol–ene click reaction. This technique significantly\nimproved the directional control and concentration of microtubules\nwithin NOA microchannels. This approach presents new possibilities\nfor the precise application of biomolecular motors in nanotechnology,\nenabling advancements in the design of microfluidic systems for complex\nbiomolecular manipulations.