DNA Hybridization: Electronic Control
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Nature has created a multitude of biological molecules that perform tasks with remarkable efficiency, accuracy, and precision. Increasingly these systems are being viewed more and more as machines because of the complexity of their function. In an effort to harness the engineering of Nature, many scientists and engineers are going beyond characterizing biological systems by investigating methods for direct manipulation. This effort has been promoted by the enormous progress in understanding the complex mechanisms and structures of biological systems. This knowledge, largely fueled by the advances in biological and biochemical tools and characterization techniques such as X-ray crystallography and NMR, has reached a point where one can describe the structure and mechanisms of large biological molecules in molecular detail. Consequently, direct manipulation of biomolecular activity is an attractive avenue for the development of new types of systems that utilize the engineering of Nature. Deoxyribonucleic acid (DNA) hybridization is a simple process that has been investigated as an interface for control, assembly, and computation. The ideal method for controlling hybridization in many of these applications would display a high degree of specificity (to control target DNA strands and leave others unaffected) and reversibility, and allow for control in vivo. Many novel methods of controlling hybridization have been developed, such as by electric field direction of DNA hybridization on a chip and optical triggering, yet each of them has limitations concerning these criterion. Here we describe a form of electronic control that directly interfaces to a DNA molecule in solution. The DNA is covalently linked to a metal nanoparticle, which can be inductively heated by a radiofrequency magnetic field (RFMF). The nanoparticle transfers heat to the DNA, denaturing it and thus switching on or off its activity. Heat dissipation into solution is rapid so once the field is turned off, the DNA can renature. This technique has been demonstrated to be both reversible and specific.