The applications of affinity biosensors: IAsys biosensor and quartz crystal microbalance to the study on interaction between Paeoniae radix 801 and endothelin-1

Paeoniae radix 801 is one of the active ingredients of the blood-activating and stasis-eliminating traditional Chinese medicine (TCM). In order to find out its action mechanism, an interaction assay system (IAsys) biosensor and a quartz crystal microbalance (QCM) were employed for the study on the specific interaction between P. radix 801 and endothelin-1 (ET-1). In the experiments, ET-1 was immobilized on the surfaces of the IAsys biosensor cuvettes and the QCM substrates by surface modification techniques, and then P. radix 801 was added to the cuvette and the substrate, separately. Then, the binding and interaction process between P. radix 801 and ET-1 was monitored. The results showed that P. radix 801 bound ET-1 specifically and the average binding masses were 1.28 ng mm−2 on the IAsys biosensor and 135 ng cm−2 (=1.35 ng mm−2) on the QCM sensor, respectively. Therefore, P. radix 801 generates bioactivity by binding and restraining the activity of ET-1. Both the IAsys biosensor and the QCM measurement techniques had high reproducibility and reliability and were found to be reliable tools to study the interaction of P. radix 801 and ET-1. This finding offers a new and effective way to study the action mechanism of P. radix 801.