Nanofluidic devices, e.g. based on nanochannels or nanopores, are networks of fluid-filled structures on a chip with dimensions ~1-100 nm.  These dimensions are on order of molecular length scales, giving rise to the ability to directly analyze, manipulate and confine single biomolecules.  In this talk I will focus on two different projects involving the interplay of new nanofluidic fabrication techniques/device concepts, application goals and physics questions related to confined/constrained polymers.  Firstly, in collaboration with nanopore start-up Nooma Bio, we have developed a dual nanopore device that features feedback-driven dynamic control over single translocating dsDNA.  In this device active control logic “catches molecules in the act” of translocating between two closely separated pores.  The molecules are then halted a “tug-of-war” configuration whereby a molecule experiences competing electrophoretic forces generated at the two pores.    The control logic then dynamically adjusts the opposing forces to scan the DNA molecule back and forth (“DNA flossing”).  We demonstrate the ability to perform 100’s of multi-scan cycles of a DNA molecule labeled with sequence specific tags.  Secondly, we use pneumatic control over confinement to trap DNA molecules in a nano-size compartment with varying anisotropy (“DNA in a box”).  This system enables us to explore how multiple interacting DNA molecules in a confined anisotropic cavity can give rise to new forms of static and dynamic organization.  Our findings are reminiscent of behavior observed in experiments in live bacteria.