title: Passively operated microfluidic device for stimulation and secretion sampling of single pancreatic islets.
abstract: A passively operated polydimethylsiloxane (PDMS) microfluidic device was designed for sampling of hormone secretions from eight individual murine pancreatic islets in parallel. Flow control was achieved using a single hand-held syringe and by exploiting inherent fluidic resistances of the microchannels (R(sampling) = 700 ± 20 kPa s mm(-3) at 37 °C). Basal (3 mM) or stimulatory (11 mM) glucose levels were applied to islets, with stimulation timing (t(stim)) minimized to 15 ± 2 s using modified reservoirs. Using enzyme-linked immunosorbent assays (ELISA) for postsampling analyses, we measured statistically equal levels of 1 h insulin secretion (1.26 ± 0.26 and 6.55 ± 1.00 pg islet(-1) min(-1), basal and stimulated; 62 islets) compared to standard, bulk sampling methods (1.01 ± 0.224 and 6.04 ± 1.53 pg islet(-1) min(-1), basal and stimulated; 200 islets). Importantly, the microfluidic platform revealed novel information on single-islet variability. Islet volume measurements with confocal reflectance microscopy revealed that insulin secretion had only limited correlation to islet volume, suggesting a more significant role for cellular architecture and paracrine signaling within the tissue. Compared to other methods using syringe pumps or electroosmotic flow control, this approach provides significant advantages in ease-of-use and device disposability, easing the burden on nonexperts.
authors.affiliation: Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States.
authors.forename: Leah A
authors.initials: LA
authors.lastname: Godwin
authors.forename: Meagan E
authors.initials: ME
authors.lastname: Pilkerton
authors.forename: Kennon S
authors.initials: KS
authors.lastname: Deal
authors.forename: Desiree
authors.initials: D
authors.lastname: Wanders
authors.forename: Robert L
authors.initials: RL
authors.lastname: Judd
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Easley
mesh_terms: D000818:Animals; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005947:Glucose / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D018613:Microscopy, Confocal / Q000379:methods; D046509:Tissue Culture Techniques / Q000379:methods
chemical_list: D004129:Dimethylpolysiloxanes; D007328:Insulin; C013830:baysilon; D005947:Glucose