title: Antigen-antibody biorecognition events as discriminated by noise analysis of force spectroscopy curves.
abstract: Atomic force spectroscopy is able to extract kinetic and thermodynamic parameters of biomolecular complexes provided that the registered unbinding force curves could be reliably attributed to the rupture of the specific complex interactions. To this aim, a commonly used strategy is based on the analysis of the stretching features of polymeric linkers which are suitably introduced in the biomolecule-substrate immobilization procedure. Alternatively, we present a method to select force curves corresponding to specific biorecognition events, which relies on a careful analysis of the force fluctuations of the biomolecule-functionalized cantilever tip during its approach to the partner molecules immobilized on a substrate. In the low frequency region, a characteristic 1/f (α) noise with α equal to one (flickering noise) is found to replace white noise in the cantilever fluctuation power spectrum when, and only when, a specific biorecognition process between the partners occurs. The method, which has been validated on a well-characterized antigen-antibody complex, represents a fast, yet reliable alternative to the use of linkers which may involve additional surface chemistry and reproducibility concerns.
authors: Biophysics and Nanoscience Centre, DEB, Università della Tuscia, Largo dell'Università, I-01100 Viterbo, Italy.
authors: Anna Rita
authors: AR
authors: Bizzarri
authors: Salvatore
authors: S
authors: Cannistraro
mesh_terms: D000936:Antigen-Antibody Complex / Q000737:chemistry*; D000937:Antigen-Antibody Reactions; D008962:Models, Theoretical; D036103:Nanotechnology; D015203:Reproducibility of Results; D013057:Spectrum Analysis / Q000379:methods*; D013816:Thermodynamics
chemical_list: D000936:Antigen-Antibody Complex