We report a means of directly controlling DNA dehybridization by radio frequency magnetic field coupling to a nanometer scale antenna covalently linked to the DNA. The method of control relies on induction heating of an Au nanocrystal, which raises the temperature of a biomolecule to which it is covalently bound, while leaving surrounding molecules relatively unaffected. Because heat dissipation in biomolecules in solution is rapid(<50 picoseconds) this switching is reversible. This technique is specific, reversible, and non-optical. Since it can be used in solution, it has the potential to be extended to systems in vivo. The ability to differentially control local temperature forms the basis of control of properties such as hybridization and enzyme activity, and has the potential of controlling many biological processes.