Rapid engineering of surface acoustic wave devices using cell-free expressed bitter receptors towards chemical sensing

The engineering of devices with various functional molecules in a high-efficient and convenient manner is crucial for biosensors towards biomedical applications. In this study, a multi-channel surface acoustic wave (SAW) device was rapid engineered with bitter receptors prepared from a cell-free protein expression system for the development of biomimetic biosensors for the detection of bitter substances. The novelty of this study mainly attributed to the utilization of DNA-directed immobilization (DDI) method to achieve high-efficient and controllable immobilization of bitter receptors onto sensitive area of SAW device. SAW device is employed as a transducer to monitor the specific interactions between bitter receptors and their ligands, which is a mass-sensitive device that can monitor tiny mass changes by recording the changes in the phase shift of SAW. The obtained results indicated that this biomimetic biosensor was able to respond to different bitter substances by generating various responsive signals, which show good stability. In addition, the distinct responsive patterns could be used to discriminating different bitter substances. It was successfully used to detect and discriminate 10 μM MgSO₄, 0.1 μM denatonium, 0.1 μM D-(−)-Salicin, and 0.1 μM quinine. This biomimetic biosensor has great potential to be used as a novel tool for chemical sensing as well as for the research of mechanisms of bitter receptor interacting with their ligands.