Single-DNA electron spin resonance spectroscopy in aqueous solutions

Magnetic resonance spectroscopy of single biomolecules under near-physiological conditions could substantially advance understanding of their biological function, but this approach remains very challenging. Here we used nitrogen-vacancy centers in diamonds to detect electron spin resonance spectra of individual, tethered DNA duplexes labeled with a nitroxide spin label in aqueous buffer solutions at ambient temperatures. This work paves the way for magnetic resonance studies on single biomolecules and their intermolecular interactions in native-like environments.