We are developing microfluidic devices that can deliver reagents to islets of Langerhans in complex temporal patterns to investigate how islets respond to these dynamic stimulations.
Mukhitov, N.; Adablah, J. E.; Roper, M. G. "Gene expression patterns in synchronized islet populations" Islets2019,11, 21-32.PDF
Adablah, J. E.; Vinson, R.; Roper, M. G.; Bertram, R. "Synchronization of pancreatic islets by periodic or non-periodic muscarinic agonist pulse trains" PLoS One2019, 14, e0211832.PDF
McKenna, J. P.; Dhumpa, R.; Mukhitov, N.; Roper, M. G.; Bertram, R. “Glucose oscillations can activate an endogenous oscillator in pancreatic islets” PLoS Computational Biology2016, 12, e1005143. PDF
Dhumpa, R.; Truong, T. M.; Wang, X.; Roper, M. G. "Measurement of the entrainment window of islets of Langerhans by microfluidic delivery of a chirped glucose waveform" Integrative Biology2015, 7, 1061-1067. PDF
Yi, L.; Wang, X.; Dhumpa, R.; Schrell, A. M.; Mukhitov, N.; Roper, M. G. "Integrated perfusion and separation systems for entrainment of insulin secretion from islets of Langerhans" Lab on a Chip2015, 15, 823-832. PDF
The fabrication of these devices can be tricky, especially when attempting to make extremely shallow channels. Follow this link to a protocol that we have found to have good success at making glass microfluidic chips. This protocol has been published and should be cited if used:
Baker, C. A.; Roper, M. G. “Continuous-flow, microchip electrophoresis fraction collector” Journal of Chromatography A 2010, 1217, 4743-4748.
Fabrication of Glass Microfluidic Devices
We utilize fast analytical systems for high speed monitoring of cellular secretion. We also use multi-color laser-induced fluorescence detection for achieving spectral resolution in cases where spatial resolution is limited.
Adams, A. G.; Bulusu, R. K. M.; Mukhitov, N.; Mendoza-Cortes, J. L.; Roper, M. G. "Online measurement of glucose consumption from HepG2 cells using an integrated bioreactor and enzymatic assay" Analytical Chemistry2019, 91, 5184-5190.PDF
Evans, K.; Wang, X.; Roper, M. G. "Chiral micellar electrokinetic chromatographic separation for determination of L- and D-primary amines released from murine islets of Langerhans" Analytical Methods, 2019, 11, 1276-1283.PDF
Bandak, B.; Yi, L.; Roper, M. G. “Microfluidic-enabled quantitative measurements of insulin release dynamics from single islets of Langerhans in response to 5-palmitic acid hydroxy stearic acid” Lab on a Chip2018, 18, 2873-2882. PDF
Wang, X.; Yi, L.; Roper, M. G. “Microfluidic device for the measurement of amino acid secretion dynamics from murine and human islets of Langerhans” Analytical Chemistry2016, 88, 3369-3375. PDF
Yi, L.; Wang, X.; Bethge, L.; Klussmann, S.; Roper, M. G. “Noncompetitive affinity assays of glucagon and amylin using mirror-image aptamers as affinity probes” Analyst2016, 141, 1939-1946. PDF
Islets of Langerhans Dynamics
At Florida state university
Measurement of Cellular Secretion
Microfluidic devices are ideal systems to automate various aspects of sample preparation. We have developed several devices that are being used to derivatize, stimulate, and collect from biological samples.
Filla, R. T.; Schrell, A. M.; Coulton, J. B.; Edwards, J. L.; Roper, M. G. “Frequency-modulated continuous flow analysis electrospray ionization mass spectrometry (FM-CFA-ESI-MS) for sample multiplexing” Analytical Chemistry2018, 90, 2414-2419. PDF
Mukhitov, N.; Spear, J. M.; Stagg, S. M.; Roper, M. G. “Interfacing microfluidics with negative stain transmission electron microscopy” Analytical Chemistry2016, 88, 629-634. PDF
Baker, C. A.; Roper, M. G. “Online coupling of digital microfluidic devices with mass spectrometry detection using an eductor with electrospray ionization” Analytical Chemistry 2012, 84, 2955-2960. PDF
Yu, Y.; Li, B.; Baker, C. A.; Zhang, X.; Roper, M. G. “Quantitative polymerase chain reaction using infrared heating on a microfluidic chip” Analytical Chemistry 2012, 84, 2825-2829. PDF