A light-addressable microfluidic device for label-free functional assays of bioengineered taste receptor cells via extracellular recording

The functional assay of chemical sensitive cells is of great importance for the preparation of sensitive elements towards the development of cell-based biosensors for chemical sensing. In this study, a novel light-addressable microfluidic device was developed by the integration of a light-addressable potentiometric sensor (LAPS) with a microfluidic chip for label-free functional assays of bioengineered taste receptor cells via extracellular recording. Extracellular potential changes of single bioengineered cells were recorded by LAPS. Microfluidic chip was capable of providing stable microenvironments for cell measurements with a well-defined concentration stimulus. Bioengineered taste receptor cells were utilized as a model of chemical sensitive cells and functional assayed by this light-addressable microfluidic device using bitter stimulation. The results indicate that this microfluidic device can efficiently monitor the membrane potential changes originated from bioengineered taste receptor cells in response to specific bitter stimulation. The bioengineered cells with responsive functions can be easily identified via the analysis on the firing rates of extracellular recording data. The expression of bitter receptors in the bioengineered taste receptor cells was further validated by the immunofluorescent staining results, which proved that the expression of specific bitter receptor was the main contribution to the responsive function of bioengineered cells. This microfluidic device can not only be used for the functional assays of chemical sensitive cells towards chemical sensing, but also suitable to be applied for the research on the chemical signal transduction mechanisms.