Authors: Jonathan G Shackman Kendra R Reid Colleen E Dugan Robert T Kennedy
Publish Date: 2012/01/30
Volume: 402, Issue: 9, Pages: 2797-2803
Abstract
A rapid microfluidic based capillary electrophoresis immunoassay CEIA was developed for online monitoring of glucagon secretion from pancreatic islets of Langerhans In the device a cell chamber containing living islets was perfused with buffers containing either high or low glucose concentration Perfusate was continuously sampled by electroosmosis through a separate channel on the chip The perfusate was mixed online with fluorescein isothiocyanatelabeled glucagon FITCglucagon and monoclonal antiglucagon antibody To minimize sample dilution the onchip mixing ratio of sampled perfusate to reagents was maximized by allowing reagents to only be added by diffusion Every 6 s the reaction mixture was injected onto a 15cm separation channel where free FITCglucagon and the FITCglucagon–antibody complex were separated under an electric field of 700 V cm−1 The immunoassay had a detection limit of 1 nM Groups of islets were quantitatively monitored for changes in glucagon secretion as the glucose concentration was decreased from 15 to 1 mM in the perfusate revealing a pulse of glucagon secretion during a step change The highly automated system should be enable studies of the regulation of glucagon and its potential role in diabetes and obesity The method also further demonstrates the potential of rapid CEIA on microfluidic systems for monitoring cellular functionThis work was supported by National Institutes of Health grant R37 DK46960 JGS was supported by an Eli Lilly Co fellowship in association with the University of Michigan KRR was partially supported by a US Dept of Education Graduate Assistance in Areas of National Need fellowship
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