Vibrational spectroscopy has advanced enormously over the past decade. The spectroscopic approaches discussed above have offered exciting opportunities to investigate membrane structure and dynamics in increasingly complex systems. One key challenge is achieving spatial resolution, and the ability to map the nanometer-scale heterogeneity for lipid organization. Nano-IR microscopy, which uses an AFM tip to localize electric fields, and thereby achieve spatial resolution, could be coupled with time-domain techniques to directly probe membrane structure and dynamics from single bonds to micron-scale length (139-142).