Dynamic nuclear polarization in liquids

Dynamic nuclear polarization (DNP) of nuclei coupled to paramagnetic centers has been used since the early years of magnetic resonance to obtain information about molecular motion and electron-nuclear spin relaxation. In the past few years, this technique has experienced a renaissance as it was recognized that it provides a means to overcome the sensitivity limits in solution and solid state NMR which is particularly important for the studies of macromolecular complexes. In this chapter, we summarize the physical and instrumental aspects of DNP in solution and we discuss the most recent experimental designs that open up the door to applications in very different fields.