Optical tweezers (OTs) exploit highly focused laser beams to create optical traps, able to manipulate the matter at the micro- and nanoscale. OTs have been increasingly used in biophysics to investigate aspects of biomolecules which are inaccessible to bulk assay, also contributing to bridge the gap between physics and biology. With the instruments available in our laboratories, we perform force spectroscopy experiments at the single molecule level, manipulating one molecule at a time and using force as a denaturant agent. Individual molecules are tethered between micrometric spheres and actuated at will to study the desired molecular process.