Publisher's Synopsis
Dispersion injection methods for determining biomolecular interaction parameters in label-free biosensing systems are provided. The methods generally relate to the use of a single analyte injection that generates a smoothly-varying concentration gradient via dispersion en route to a sensing region possessing an immobilized binding partner. The present method incorporates the use of an internal standard which provides a reference as to the dispersion conditions present which can then be used to calculate an effective diffusion coefficient for the analyte of interest based on a universal calibration function. The effective diffusion coefficient can then be incorporated into the appropriate dispersion model to provide a calibrated dispersion model. The calibrated dispersion model can then be incorporated into the desired interaction model to provide a reliable representation of the analyte concentration at the sensing region at any time during the injection. The use of the internal standard and universal calibration function permit use of a wide range of injection conditions which may not otherwise be consistent with a particular dispersion model. Thus, the present methods allow for higher flow rates and lower sample volumes thereby increasing assay speed and decreasing sample consumption.