A whole animal-based biosensor for fast detection of bitter compounds using extracellular potentials in rat gustatory cortex

Bitterness detection has attracted increasing attention in science and industry. However, existing methods often suffer from drawbacks such as long detection time and low specificity. Mammalian gustatory systems have been acknowledged as valid chemosensing systems, and thus the potential of utilizing intact rat gustatory system is investigated in bitterness detection and screening. Rat's gustatory cortex (GC) functions as the central processor of gustation, and GC neurons are coupled with microelectrode array under anesthesia to reduce moving artifacts. By recording extracellular potentials in GC, response patterns evoked by bitterness are widely discovered in both single neuron and neural network activities. As a result, signals are observed to carry abundant information about taste qualities within the first 4 s after bitterness delivery, and the purpose of fast detection is achieved. Based on support vector machine, this biosensor can detect and recognize bitterness with an accuracy of 94.05%. Moreover, the high specificity to bitter compounds is guaranteed by single bitter responsive neuron which can generate highly specific firing patterns in spite of the existence of interference. Quantitative study also reveals that this in vivo system is sensitive enough for further applications. In conclusion, this whole animal-based biosensor is able to detect bitterness especially with strict constrains in time and provides new platform for bitterness screening with high specificity.