Long term kinetic measurements revealing precision and general performance of surface plasmon resonance biosensors

- Major error sources: surface phenomena and regeneration, and dilution steps.
- High precision can be achieved, e.g. approx. 3-6% RSD% for dissociation constants KD.
- Control charts contribute to an overall better system performance.

This work presents an extensive parameter list that facilitates a survey of biosensor performance using Biacore instruments for kinetic binding studies. Six long term measurements were performed using a strongly interacting antigen-antibody (β2 microglobulin) system. Both Single Cycle Kinetic (SCK) and Multi Cycle Kinetic (MCK) were executed each with five different analyte concentrations. The overall comparison of the long term monitored parameters, like the dissociation constant (KD with approximately 3-6% relative percental standard deviation), the association and dissociation rate constants (ka, kd), the analyte binding capacity (Rmax), chi2 and the sum of the absolute values of the residuals, revealed the delicate factors that make the system performance vulnerable. The main influential factors on kinetic performance were the regeneration conditions, the quality of the sensor surface, the usage time and alteration of the sensor surface, the dilution series and the number of run cycles (about 250-600 per chip). Moreover the direct comparison of MCK and SCK uncovered distinct differences in the accuracy of the KD values. The study of sensor chips from two manufacturers showed distinct differences in the precision of the data. Using control charts for the surveillance of these parameters contributes to an overall better system performance.