ANYL 231 |
| Many chemical materials and processes depend on suspensions of fine particles in water, for chemical processing and delivery of organic materials while avoiding volatile organic solvents. Polymer colloids are used in time-released drug delivery and biological particles (cells, vesicles, viruses) are critical structures for biological function. To understand these structures, there is a need for spectroscopic methods that can determine the chemistry of micron and sub-micron particles and report variability in composition on a single-particle basis. Optical-trapping methods combined with confocal Raman microscopy are well suited to the challenge of single-particle spectrochemical chemical analysis. Sub-micron sized particles can be trapped with modest optical powers and observed for hours, which allows changes in chemical structure to be followed over time. We have investigated the sensitivity and spatial selectivity of optical-trapping confocal-Raman microscopy for the analysis of sub-micron particles. Applications of this methodology to monitoring of solid-phase synthesis steps, measuring photopolymerization rates of individual emulsion particles, determining the temperature-dependent structure of phospholipid bilayers in single lipid vesicles, and the accumulation of molecules in liposome carriers will be presented. |
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Honoring Mary Wirth, Recipient of the Spectrochemical Analysis Award
1:30 PM-5:00 PM, Tuesday, 12 September 2006 Moscone Center -- Room 123, Oral
Division of Analytical Chemistry |