Prof. Mitchell Winnik, University of Toronto

Metal-chelating polymers and polymernanoparticles designed for use in bioassays

We are interested in bioassays based upon inductively coupled plasma mass spectrometry [ICP-MS], a technique widely used in mining and metallurgy for its ability to measure quantitatively, with high sensitivity, the presence of different metals in a sample. In analogy with fluorescence based bioassays, where one uses quantum dots or fluorescent dyes as labels, we use lanthanide (Ln) metal ions as labels. For example, by labeling antibodies with metal-chelating polymers and different Ln ions, we have been able to carry out highly multiplexed assays for phenotyping human leukemia cells. I will briefly describe the new technique of mass cytometry, which allows us to quantify 20 biomarkers on a cell-by-cell basis. Then I will describe polystyrene nanoparticles carrying ca 2000 Ln ions and their use in assays of cell adhesion. Then I will present the synthesis of core-shell polymer nanogels containing much higher amounts of metal ions in the form of doped LaF3 nanoparticles. These can be taken up by a variety of cells by non-specific endocytosis. They become incorporated into endosomes, where they appear not to have any effect on cell activity. The long term goal this nanoparticle project is to be able to label cells such as stem cells in order to monitor their differentiation.

For more information contact Prof. L. Andrew Lyon (404-894-4090).