Auburn University
Auburn University
 

Auburn University > COSAM > Academic Departments > Chemistry & Biochemistry > Faculty >

Christopher J. Easley Christopher J. Easley
Assistant Professor

Vanderbilt University Medical Center, NIH Postdoctoral Fellow, 2006-2008
University of Virginia, Ph.D., 2006
Mississippi State University, B.S., 2002

Phone: (334) 844-4043
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Bioanalytical Chemistry:  Microfluidics, Fluorescence Microscopy, Electrophoresis, Molecular Biology, Aptamers, Intercellular Communication, Diabetes, Quorum Sensing

Zinc Secretion from Pancreatic Islet     Research in the Easley Laboratory is focused on the combination of several key techniques—microfluidics, quantitative fluorescence microscopy, electrophoresis, and molecular biology—to ultimately study fundamental chemical and biophysical mechanisms involved in cell-to-cell communication. Of central importance to these studies is the development and implementation of innovative chemical analysis systems that allow my group to perform unique experiments on biological systems; thus, microanalytical technology is emphasized throughout our research as a general tool to enhance analytical bandwidth. We are making improvements upon well-established analytical and biological techniques, but we are also striving to discover new approaches for nanoliter-scale fluidic control as well as fluorescent and chemical sensing, providing us with a set of tools that are unique to our laboratory.

    -The unifying theme of our research is to combine nanoliter-scale fluid control strategies, capillary electrophoresis, nucleic acid sensors, and engineered fluorescent proteins to enhance our understanding of cell-to-cell communication in both bacterial (quorum sensing) and mammalian (glucose metabolism, diabetes) systems.

Droplet Fluidics Fluid control strategies for collection, storage, and analysis of cellular secretions. The microfluidic platform provides unique capabilities to precisely control the cellular microenvironment. Our group is capable of designing and fabricating microfluidic devices to trap or culture cells and sample their secretions using droplet (digital) fluidics. Secretions are confined into picoliter-volume droplets, providing high resolution temporal preservation of chemical information from secretory events. We are particularly interested in testing for the presence of paracrine communication between live islets of Langerhans isolated from the pancreatic tissue of mice. We are also interested in studying the secretory events involved in quorum sensing among bacterial colonies of Pseudomonas aeruginosa.

Development of fluorescent nucleic acid sensors. DNA or RNA aptamers are oligonucleotide fragments that have been selected for high affinity and specificity of their tertiary structure to targets ranging from small molecules to proteins. The in vitro method for aptamer selection, systematic evolution of ligands by exponential enrichment (SELEX), is based on multiple cycles of binding to an immobilized target (protein, small molecule) followed by sequence amplification by the polymerase chain reaction (PCR). We are using a modified version of SELEX that uses capillary electrophoresis, referred to as CE-SELEX (Mendosa and Bowser, JACS, 2004, 126, 20-21.) to select aptamers against secretory proteins and hormones from mammalian and bacterial cells. These high affinity aptamers will be used as blocking agents or stimuli of intercellular communication, providing our group with novel, customized control mechanisms to aid in our understanding of these processes.

Engineering proteins for imaging and rapid electrophoretic quantitation of gene expression. We are interested in developing fluorescent protein constructs indicative of the expression of proteins involved in the quorum sensing circuits of P. aeruginosa (lasR/lasI and rhlR/rhlI). Capillary or microchip electrophoresis is used to quantify this gene expression through fluorescence detection. We hope to correlate the expression of these proteins with secretions of autoinducers (N-acyl-homoserine lactones) with high temporal resolution. This way, we can correlate bacterial behavior, gene expression, and secretions in different microenvironments defined by our microfluidic devices.

 

Selected Publications:

Mao, S.; Benninger, R. K. P.; Jackson, D.; Yan, Y.; Petchprayoon, C.; Jackson, D. K.; Easley, C. J.; Piston, D. W.; Marriott, G. “Optical lock-in detection of fluorescence resonance energy transfer using synthetic and genetically-encoded optical switches.” Biophys. J. (published online Feb. 15, 2008).

Easley, C. J.; Humphrey, J. A. C.; Landers, J. P. “Thermal isolation of microchip reaction chambers for rapid non-contact DNA amplification.” J. Micromech. Microeng., 2007, 17, 1758-1766.

Easley, C. J.; Karlinsey, J. M.; Bienvenue, J. P.; Legendre, L. A.; Roper, M. G.; Feldman, S. H.; Hughes, M. A.; Hewlett, E. L.; Merkel, T. J.; Ferrance, J. P.; Landers, J. P. “A fully-integrated microfluidic genetic analysis system with sample in-answer out capability.” Proc. Natl. Acad. Sci. USA, 2006, 103, 19272-19277.

Easley, C. J.; Karlinsey, J. M.; Landers, J. P. “On-chip pressure injection for integration of infrared-mediated DNA amplification with electrophoretic separation.” Lab Chip, 2006, 6, 601-610. [COVER ARTICLE]

Easley, C. J.; Legendre, L. A.; Roper, M. G.; Wavering, T. A.; Ferrance, J. P.; Landers, J. P. “Extrinsic Fabry-Perot interferometry for non-contact temperature control of nanoliter volume enzymatic reactions in glass microchips.” Anal. Chem., 2005, 77, 1038-1045.

Easley, C. J.; Jin, L. J.; Presto-Elgstoen, K. B.; Jellum, E.; Landers, J. P.; Ferrance, J. P. “Capillary electrophoresis with laser-induced fluorescence detection for laboratory diagnosis of galactosemia.” J. Chrom. A, 2003, 1004, 29-37.