Comparison of the QCM and the SPR method for surface studies and immunological applications

A comparison between the quartz-crystal microbalance (QCM) and surface plasmon resonance (SPR) using an especially designed flow-through cell for simultaneous measurements and flow-injection analysis (FIA) is presented. We compare the effects due to unspecific binding of bovine serum albumin (BSA) to gold surfaces, specific binding between BSA and monoclonal antibodies, regeneration experiments, serum experiments with HIV antigens and the influence of the bulk properties of liquid samples. The basic theory and its consequences on measurement signals and experimental methods are discussed. The fundamental problem of the comparability of different measurement principles is considered. We suggest guide parameters, which allow an objective judgement of the performance. We do not find any advantage of one particular system concerning sensitivity and cross sensitivity.