Using Tunable Nanoscale Confinement to Image and Manipulate DNA

Using Tunable Nanoscale Confinement to Image and Manipulate DNA Daniel Berard, Jason S. Leith, Francois Michaud, Sabrina R. Leslie Department of Physics, McGill University, Canada [email protected] We present a modular microscopy device that transforms a basic inverted fluorescence microscope into a versatile single-molecule imaging and diagnostic system, with applications in the biomedical, biophysical and materials sciences. The device employs a recently developed and accessible imaging approach, Convex LensInduced Confinement (CLIC), delivering key advantages based on its tunable nanoscale imaging geometry: sensitive detection and enhanced background suppression; minimal required analyte volume (~L); direct visualization of molecular interactions and dynamics over extended time periods (seconds to minutes); and direct manipulation of molecular conformations [1]. The presented CLIC device loads the sample into a flow-cell using a microfluidics system and mechanically deforms the flow-cell, creating a tunable, nanoscale imaging chamber. A powerful feature of CLIC imaging is the ability to manipulate and visualize single molecules under a continuum of applied confinement, from the micrometer to nanometer scale. It overcomes a key challenge faced by existing nanofluidic technologies of delivering molecules from a microscale loading environment into a nanoscale imaging environment. We demonstrate the device’s ability to manipulate the conformations of DNA molecules in free-solution, providing a new approach to partitioning and probing their physical properties. Further, combining CLIC imaging with surface-lithography presents a powerful approach to controllably manipulating and trapping molecules over a wide range of imaging conditions. Fluorescence Microscopy (180.2520); 170.3880 Medical and biological imaging; 170.3890 Medical optics instrumentation. 1. Motivation for Improved Single-Molecule Fluorescence Microscopy