Single-molecule biophysical analysis with double nanohole optical tweezers

For over a decade, our group has been trapping and analyzing single proteins using a double nanohole in a metal film. Our recent investigations have sought to improve the nanofabrication, including bottom-up mass-fabrication and a new fiber-based platform for microwell format investigation. We have also been developing approaches to modify the environment around a single trapped protein, for example, by integrating microfluidics and allowing for varying the background temperature. This allows for measuring properties like the optical size, hydrodynamic size, charge and thermophoretic properties a trapped protein. These new capabilities will be presented in this work.