A sperm-cell-based biosensor using a fluorescence probe for responsive signal readout toward bitter flavor detection

Bitter flavor detection has attracted extensive attention in industry and basic research due to pharmacological and food safety issues. Opportunities exist to extend the conventional methods of bitter flavor evaluation in performance and operation. This study proposes a novel sperm-cell-based biosensor (SCB) that utilizes living mouse spermatids as the primary sensing element, employs Fluo 4-AM as a transducer and works in conjunction with flow cytometry to realize the rapid quantitative detection of bitter compounds. The preparation conditions of the SCB were optimized with different quinine concentrations, and quinine and two other bitter compounds were employed to verify the sensing properties. Furthermore, the responses of the SCB to five basic flavor types were characterized to evaluate the sensor specificity. The SCB enabled preliminary classification of three bitter substances by using principal component analysis (PCA). The results revealed that the SCB is convenient, inexpensive and easy to use and can respond to bitter compounds in a dose-dependent manner with high sensitivity, high specificity and a low limit of detection, providing a novel and efficient approach for comprehensive evaluation of bitter substances in many fields, such as the pharmaceutical and food industries and in biosafety.