Fabrication of High Aspect Ratio Nanoconfined Environments for Single-Molecule Experiments

High aspect ratio (width to height) nanoconfined environments create a slit-like environment that can be used to mimic interfaces, making them valuable tools for investigating the physics of single polymeric molecules. In this study we demonstrate the fabrication of optically transparent nanofluidic devices using borosilicate glass substrates. We use photolithography and wet etching to pattern multiple nanochannels with aspect ratios between 20 and 100× onto a single, standard size glass wafer. We characterize all etched nanochannels with optical profilometry, providing detailed statistics about channel dimensions and roughness. We use a combination of ammonium hydroxide activated, low temperature bonding and high temperature thermal annealing to add glass covers to nanochannels without causing channel collapse. We laser cut inlet/outlet ports into glass covers to produce fully functional fluidic devices, and finally dice multiple nanofluidic devices out of a single glass wafer, allowing for the processing of multiple nanoconfined environments in parallel. These optically transparent nanofluidic devices enable measurements of dynamic confined polymer behavior using single-molecule fluorescence microscopy.