Single-molecule biophysics offers unique insight into the dynamics and mechanistics of biomolecules, unlimited by the inevitable averaging associated with ensemble measurements. Apart from established single-molecule characterization techniques based on optical and force spectroscopies, electronic sensors are emerging as a novel approach for single-molecule biophysics. These ultraminiature, point-functionalized circuits offer a powerful method to isolate and probe biomolecules, with the ability to detect tiny changes in charge or conformation over a uniquely wide range of time scales. In particular, we have demonstrated signal acquisition in fast time scales down to the microsecond range, combined with extended, multi-hour measurement times on the same molecule. In this presentation, I will present recent studies exploring the conformational dynamics of nucleic acids. I will demonstrate how nanoelectronic biosensors can detect, through quantized fluctuations in electrical conductance, successive hybridization and melting events in double-stranded DNA, as well as fluctuations between different folded states in single-stranded telomeric DNA and riboswitch RNA sequences. Electronic sensors open the way towards developing integrated genomic analyses, as well as investigating the mechanistic and dynamics landscape of a variety of biomolecules.