Unveiling the influence of device stiffness in single macromolecule unfolding

Single-molecule stretching experiments on DNA, RNA, and other biological macromolecules opened up the possibility of an impressive progress in many fields of Life and Medical sciences. The reliability of such experiments may be crucially limited by the possibility of determining the influence of the apparatus on the experimental outputs. Here we deduce an analytical model that we show to be coherent with previous numerical results and that quantitively reproduce AFM experimental tests on titin macromolecules and P-selectin AFM experiments with variable probe stiffnesses. We believe that the obtained analytical description can represent an important step forward in the interpretation of Single Molecule Force Spectroscopy experiments and intermolecular interactions phenomena.