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

Recent Advances in Bitterness-Sensing Systems

Bitterness is one of the basic tastes, and sensing bitterness plays a significant role in mammals recognizing toxic substances. The bitter taste of food and oral medicines may decrease consumer compliance. As a result, many efforts have been made to mask or decrease the bitterness in food and oral pharmaceutical products. The detection of bitterness is critical to evaluate how successful the taste-masking technology is, and many novel taste-sensing systems have been developed on the basis of various interaction mechanisms. In this review, we summarize the progress of bitterness response mechanisms and the development of novel sensors in detecting bitterness ranging from commercial electronic devices based on modified electrodes to micro-type sensors functionalized with taste cells, polymeric membranes, and other materials in the last two decades. The challenges and potential solutions to improve the taste sensor quality are also discussed.

Progress in the Development of Detection Strategies Based on Olfactory and Gustatory Biomimetic Biosensors

The biomimetic olfactory and gustatory biosensing devices have broad applications in many fields, such as industry, security, and biomedicine. The development of these biosensors was inspired by the organization of biological olfactory and gustatory systems. In this review, we summarized the most recent advances in the development of detection strategies for chemical sensing based on olfactory and gustatory biomimetic biosensors. First, sensing mechanisms and principles of olfaction and gustation are briefly introduced. Then, different biomimetic sensing detection strategies are outlined based on different sensing devices functionalized with various molecular and cellular components originating from natural olfactory and gustatory systems. Thereafter, various biomimetic olfactory and gustatory biosensors are introduced in detail by classifying and summarizing the detection strategies based on different sensing devices. Finally, the future directions and challenges of biomimetic biosensing development are proposed and discussed.

Hybrid Integrated Cardiomyocyte Biosensors for Bitter Detection and Cardiotoxicity Assessment

Among basic taste sensations, bitter taste is vital to the survival of mammals due to its indispensable role in toxin prediction or identification, so the identification of bitter compounds is of great value in the pharmaceutical and food industry. Recently, bitter taste receptor (T2Rs)-based biosensors have been developed for specific bitter detection. However, the taste biosensors based on taste cells/tissues suffer from simple function, low sensitivity, low content, and limited parameters. Here, to establish a high-content, highly sensitive, and multifunctional taste biosensor, we developed a multifunctional hybrid integrated cardiomyocyte biosensor (HICB) for bitter detection. Due to the expression of bitter taste receptors in cardiomyocytes, the HICB can recognize the specific bitter agonists by synchronously recording the extracellular field potential (EFP) and mechanical beating (MB) signals from the cultured cardiomyocytes in vitro. Multiple feature parameters were defined and extracted from the electromechanical signals of cardiomyocytes to analyze the specific responses to four typical bitter compounds. The radar map, heat map, and principal component analysis (PCA) were used to visualize and classify the specific responses. Moreover, bitter-induced cardiotoxicity also was chronically evaluated, and these bitter compounds presented an inhibition effect on the electrophysiological and contractile activities of cardiomyocytes. This high-content HICB offers an alternative platform for both bitter detection and cardiotoxicity assessment, showing promising applications in the fields of taste detection and toxicity screening.

Tofacitinib suppresses mast cell degranulation and attenuates experimental allergic conjunctivitis

BACKGROUND

Allergic conjunctivitis (AC), a common eye inflammation that affects patients' health and quality of life, is still a therapeutic challenge for ophthalmologists. Tofacitinib, a new Janus kinase (JAK) inhibitor, has been successfully used in the treatment of several disorders. Nonetheless, its effect in AC and the potential anti-allergic mechanisms are still unclear. The objective of the current study was to explore the roles of tofacitinib in preventing AC and elucidate the potential underlying mechanisms.

METHODS

Tofacitinib was used topically in BALB/c mice with experimental allergic conjunctivitis (EAC). Ocular allergic symptoms and biological modifications were examined. To assess the anti-allergic mechanisms of tofacitinib, RBL-2H3 cells and HUVECs were cultured in vitro. The inhibitory effects and mechanisms of tofacitinib were studied and measured by real-time quantitative PCR, ELISA, western blot analysis, and flow cytometry.

RESULTS

Topical administration of tofacitinib reduced the clinical symptoms of OVA-induced EAC, with a substantial mitigation in inflammatory cell infiltration, histamine release, and TNF-α mRNA as well as IL-4 mRNA expression. In vitro, tofacitinib repressed the degranulation and cytokine production in RBL-2H3 cells and reduced histamine-induced vascular hyperpermeability. The underlying mechanism might involve the downregulation of phosphorylation of JAK3/STATs signaling molecules in RBL-2H3 cells and HUVECs.

CONCLUSIONS

Our findings provide evidence that tofacitinib prevented EAC by targeting the JAK3/STATs pathway. We recommend the use of tofacitinib as an innovative approach for the treatment of AC.