Microfluidic analytical systems for assaying dynamic cellular secretions

Description:
Islets of Langerhans are the endocrine portion of the pancreas and are composed of several cell types that release peptide hormones into the bloodstream for regulating glucose levels. Proper control of blood glucose is dependent on the amounts and dynamics of hormones released from these cells. Because the dynamic profiles of hormone secretion are essential to proper glucose control, examining secretion from single or small groups of islets are essential, necessitating analytical tools with high sensitivity. Microfluidic systems are an ideal platform to interrogate islets as they reduce dilution and can be used to deliver complex glucose profiles like those observed in vivo. We have developed a number of analytical approaches that use microfluidic systems to measure hormone and small molecule secretions from single or small groups of islets. Initially, microfluidic electrophoretic assays were used; however, while highly sensitive, the microfluidic systems were difficult to use due to the shallow channels required to limit Joule heating. As such, a homogeneous fluorescence anisotropy assay was developed which allowed for larger channels. To increase the throughput of the assay and make it more amenable to screening applications, a fluorescence anisotropy imaging system was employed for measurement of insulin secretion from 12 groups of islets in parallel with minimal fluidic inputs. To automate the system further and allow for smooth operation, approaches to integrate microfluidic valves and other microfluidic elements will be discussed. Finally, the application of antibody-free assays providing multi-analyte monitoring will be described. The use of microfluidic systems to hold islets and couple with liquid chromatography or solid phase extraction and mass spectrometry detection will be described. These systems offer the potential for combining the benefits of microfluidics with high information content detection.

Speaker: Michael Roper - Florida State University
Michael Roper obtained his PhD from the University of Florida in 2003 and then performed postdoctoral research at the University of Virginia. Since joining the Department of Chemistry and Biochemistry and the Program in Molecular Biophysics at Florida State University in 2006, the Roper research group has developed powerful analytical systems for the quantitative measurement of small molecules and peptides secreted from cellular tissues with high temporal resolution. In particular, his group examines the dynamic secretion profiles of glucose-regulating hormones from the endocrine portion of the pancreas, islets of Langerhans. Dr. Roper has received the 2013 American Chemical Society Division of Analytical Chemistry’s Young Investigator Award in Separation Science and the 2018 Mid-Career Award by the American Electrophoresis Society.