Receptomics: Tongue-on-a-chip with novel opportunities for food screening

Within the food and flavour industry it is considered a “holy grail” to measure the sensory aspects of taste and aroma quantitatively and independent from a taste panel. A microfluidic tongue- or nose-on-a-chip platform could be a system to emulate sensory perception into an instrument by monitoring the activation of specific taste and olfactory receptors in response to food samples. The complexity of food matrices, however, presents a large hurdle for the development and practical application of such systems. The issues are related to the frequent occurrence of (i) sample fluorescence, and (ii) non-specific host cell responses. In this paper we outline how we tackled these two issues with some practical examples; the sample fluorescence of coffee and the host cell response to bitter gourd and tomato juice. With the microfluidic receptor array developed in our lab, we were able to extract specific signals despite the sample fluorescence and host cell response effects. Reliable results could be obtained from these samples based on internal calibrations on-chip and sample controls. The fluidic measurement setup allows repeated exposures of the entire cell array to contrasting samples. With this strategy we could extract receptor-specific response trends to samples independent from generic host cell responses and sample fluorescence artefacts