DYNAMIC FORCE SPECTROSCOPY
POLYMER APPROACH
Dynamic force spectroscopy can probe the free energy landscape of interacting bonds, but interpretations polymer-mineral interactions are challenged by the complex mechanical behavior of polymers. We recently restated the difficulties inherent to applying DFS to polymer-linked adhesion and present an approach to gain quantitative insight into
polymer-mineral binding.
Our formulation of a DFSpolymer approach applies to both the equilibrium and nonequilibrium regimes and it should be adapted to describe the bond behavior and binding mechanisms of elastic (bio)polymers.
Our approach add to the applicability of the DFS method to complex biopolymers and has a range of implications including bioinspired approaches to materials design and synthesis utilized such interactions to advance medical and technological applications, such as nanoparticles for ingestion, bone implants, and responsive materials.
METHOD IN SHORT:
DFSpolymer approach in short: a) A biomolecule is covalently attached to an AFM tip and brought into contact with a surface. b) By varying the ret raction velocities, we obtain 2 regimes: i) a near-equilibrium regime, where the retraction velocity is slow enough to record events of the bond formation and breaking, and where an equilibrium force can be extracted (feq). ii) a kinetic regime, where the rupture force depends asymptotically on the retraction rate from where the kinetic off-rate and distance to the transition state can be extracted. c)The technique requires 10,000s of force curves. Through a polymer extension analysis of the last rupture event of each force curve and by fitting the resulting dynamic force spectra, the mechanistic bond parameters can be extracted and insight into the energy landscape is obtained. Data from Sand et al.
