Single molecule studies are increasingly important in biophysics. The Perkins group focuses on developing precision single-molecule techniques and applying them to answer a variety of biological questions, such as: how motor proteins transduce chemical energy into physical motion? And, how does the structure and dynamics of membrane proteins affect their functions? We developed a single-molecule optical-trapping assay with Ångström-scale stability and resolution in all three dimensions (3D). We are applying these techniques to study DNA-based molecular motors, the folding/unfolding kinetics of RNA structures, DNA overstretching and biologically derived force standards. We also developed an atomic force microscope that is a 100-fold more stable than current state of the art as well as improving the force stabilty and force precision of bio-AFM. We are currently pursuing applications of focus-ion-beam modified cantilevers to protein folding studies.