Membrane-induced Confinement of DNA in Pneumatically-actuated Nanofluidic Device

We present a pneumatically-actuated nanofluidic platform that has the capability of dynamically controlling the confinement environment of biomolecules in solution. Our approach, based on flexible nanoscale nitride membranes, provides a facile and economical means of actuated confinement using standard microfabrication techniques. DNA is loaded into nanofluidic slits and hydrodynamic flow is used to drive the molecules over embedded features such as cavities and concentric rings. The device is bonded with a membrane lid that can be deflected pneumatically to dynamically confine passing DNA. By carefully calibrating the pressure applied to the membrane, we can control membrane deflection to tune the deflection rate and degree of confinement. Using this approach, we study the trapping rate of DNA in embedded features as a function of deflection rate and feature geometry to obtain loading conditions that optimize molecular trapping. We also study the effect of non-equilibrium forcing, arising from confinement variation, on dynamical and conformational behavior of confined molecules.