NDSU Calendar

Thursday, January 31, 2013
Department of Chemistry and Biochemistry with co-sponsor, Center for Life Sciences (Conference/Workshop/Seminar)

Kenneth A. Christensen, Department of Chemistry, Clemson University, Clemson, South Carolina, will present a seminar entitled, "Spectroscopic Probes and Sensors for Analysis of Live Cells".
Everyone is welcome!
Conjugated polymer nanoparticles (CPNs) are a promising class of luminescent nanoparticles that have substantially brighter emission than both traditional organic fluorophores and quantum dots. We have investigated the interactions of these nanoparticles with cells and evaluated their use as both targeted and fluid-phase labels in cell biology applications. Upon CPN uptake, no upregulation of inflammatory markers or changes in cell proliferation are observed, suggesting that these nanoparticles are largely biologically innocuous. Methods for functionalizing CPN surfaces were developed and tested; functionalized nanoparticles show enhanced colloidal stability in both physiological buffers and media and affect uptake and localization in cells. Intracellular sensing using functionalized CPNs has been achieved in cells and is demonstrated experimentally using a ratiometric oxygen sensor composed of CPNs doped with platinum porphyrin and encapsulated within a PEG-lipid layer. This ratiometric CPN sensor shows both sensitivity and specificity to oxygen in live cells.

In addition, our laboratory applies traditional organic dyes in innovative ways to achieve intracellular sensing. Two examples will be described. The first is the use of a dye pair to quantify intracellular water transport across the membranes of subcellular organelles in live mammalian cells. Using this methodology, we observe changes in water permeability over the course of macropinosome maturation, and identify a pH-dependence in observed membrane water permeability in macropinosomes. These measurements are the first step in understanding the processes of water transport within the cell. Finally, we utilize a targeting peptide-fluorescein construct to deliver a ratiometric pH sensor to the glycosomes of the eukaryotic parasite Trypanosoma brucei. Glycosome function is essential to parasite survival, and is responsive to external stimuli. We report results of studies that quantify the microenvironment inside the glycosome. Information gained from these studies show how external cues affect glycosomal function, as the groundwork for trypanocidal therapies that target this unique organelle.
More information...
Location: Ladd 107
Price: Free
Host: Department of Chemistry and Biochemistry and Center for Life Sciences, co-sponsor
Contact: Wendy J. Leach
E-Mail: wendy.leach@ndsu.edu


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