title: Quantitative and temporal control of oxygen microenvironment at the single islet level.
abstract: Simultaneous oxygenation and monitoring of glucose stimulus-secretion coupling factors in a single technique is critical for modeling pathophysiological states of islet hypoxia, especially in transplant environments. Standard hypoxic chamber techniques cannot modulate both stimulations at the same time nor provide real-time monitoring of glucose stimulus-secretion coupling factors. To address these difficulties, we applied a multilayered microfluidic technique to integrate both aqueous and gas phase modulations via a diffusion membrane. This creates a stimulation sandwich around the microscaled islets within the transparent polydimethylsiloxane (PDMS) device, enabling monitoring of the aforementioned coupling factors via fluorescence microscopy. Additionally, the gas input is controlled by a pair of microdispensers, providing quantitative, sub-minute modulations of oxygen between 0-21%. This intermittent hypoxia is applied to investigate a new phenomenon of islet preconditioning. Moreover, armed with multimodal microscopy, we were able to look at detailed calcium and KATP channel dynamics during these hypoxic events. We envision microfluidic hypoxia, especially this simultaneous dual phase technique, as a valuable tool in studying islets as well as many ex vivo tissues.
authors.affiliation: Department of Mechanical Engineering, University of Michigan-Dearborn.
authors.forename: Joe Fu-Jiou
authors.initials: JF
authors.lastname: Lo
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Zidong
authors.initials: Z
authors.lastname: Li
authors.forename: Zhengtuo
authors.initials: Z
authors.lastname: Zhao
authors.forename: Di
authors.initials: D
authors.lastname: Hu
authors.forename: David T
authors.initials: DT
authors.lastname: Eddington
authors.forename: Jose
authors.initials: J
authors.lastname: Oberholzer
mesh_terms: D000818:Animals; D015687:Cell Hypoxia / Q000502:physiology; D005947:Glucose / Q000008:administration & dosage; D007515:Islets of Langerhans / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D008856:Microscopy, Fluorescence; D010100:Oxygen / Q000008:administration & dosage*; D059010:Single-Cell Analysis / Q000295:instrumentation / Q000379:methods
chemical_list: D005947:Glucose; D010100:Oxygen