SAW Sensor System for Marker‐Free Molecular Interaction Analysis

A chip‐based biosensor system for marker‐free detection of affinity and molecular interaction kinetics was developed. It applies surface‐acoustic‐waves. Combined with a novel double‐frequency measurement‐mode, which assures reliable reference measurements, it allows a precise real‐time detection of mass loading and viscosity alteration. The system is equipped with five independently working channels, which enable it to simultaneously perform different, e.g., reference measurements. Exemplarily performed investigations of the association of thrombin and antithrombin antibodies demonstrated the applicability of the system to affinity and kinetic analyses. The system yielded a mean value for the equilibrium dissociation constant of K D=116±9 nM, which compares well with the supplier specification.