title: A High-Throughput Automated Microfluidic Platform for Calcium Imaging of Taste Sensing.
abstract: The human enteroendocrine L cell line NCI-H716, expressing taste receptors and taste signaling elements, constitutes a unique model for the studies of cellular responses to glucose, appetite regulation, gastrointestinal motility, and insulin secretion. Targeting these gut taste receptors may provide novel treatments for diabetes and obesity. However, NCI-H716 cells are cultured in suspension and tend to form multicellular aggregates, preventing high-throughput calcium imaging due to interferences caused by laborious immobilization and stimulus delivery procedures. Here, we have developed an automated microfluidic platform that is capable of trapping more than 500 single cells into microwells with a loading efficiency of 77% within two minutes, delivering multiple chemical stimuli and performing calcium imaging with enhanced spatial and temporal resolutions when compared to bath perfusion systems. Results revealed the presence of heterogeneity in cellular responses to the type, concentration, and order of applied sweet and bitter stimuli. Sucralose and denatonium benzoate elicited robust increases in the intracellular Ca(2+) concentration. However, glucose evoked a rapid elevation of intracellular Ca(2+) followed by reduced responses to subsequent glucose stimulation. Using Gymnema sylvestre as a blocking agent for the sweet taste receptor confirmed that different taste receptors were utilized for sweet and bitter tastes. This automated microfluidic platform is cost-effective, easy to fabricate and operate, and may be generally applicable for high-throughput and high-content single-cell analysis and drug screening.
authors.affiliation: Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan. s102035802@gmail.com.|Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli 35053, Taiwan. s102035802@gmail.com.
authors.forename: Yi-Hsing
authors.initials: YH
authors.lastname: Hsiao
authors.affiliation: Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan. chsu@nhri.org.tw.|Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli 35053, Taiwan. chsu@nhri.org.tw.
authors.forename: Chia-Hsien
authors.initials: CH
authors.lastname: Hsu
authors.affiliation: Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan. chihchen@mx.nthu.edu.tw.|Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan. chihchen@mx.nthu.edu.tw.
authors.forename: Chihchen
authors.initials: C
authors.lastname: Chen
mesh_terms: D002118:Calcium / Q000819:agonists / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002460:Cell Line; D019858:Enteroendocrine Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000037:antagonists & inhibitors / Q000494:pharmacology; D031104:Gymnema sylvestre / Q000737:chemistry; D057166:High-Throughput Screening Assays / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D056656:Lab-On-A-Chip Devices; D008954:Models, Biological; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D059010:Single-Cell Analysis / Q000295:instrumentation / Q000379:methods*; D013395:Sucrose / Q000031:analogs & derivatives / Q000494:pharmacology; D013649:Taste / Q000187:drug effects / Q000502:physiology; D055697:Taste Perception / Q000187:drug effects* / Q000502:physiology; D059008:Time-Lapse Imaging / Q000295:instrumentation / Q000379:methods*
chemical_list: D002118:Calcium; D005947:Glucose; D010936:Plant Extracts; D000644:Quaternary Ammonium Compounds; D043562:Receptors, G-Protein-Coupled; D013395:Sucrose; C431926:taste receptors, type 1; C026285:trichlorosucrose; C043414:denatonium
keywords: automated system; calcium imaging; denatonium benzoate; enteroendocrine cell; glucose; high throughput; microfluidic; single cell; sucralose; taste cell