Temperature-Controlled Confocal Raman Microscopy to Detect Phase Transitions in Phospholipid Vesicles
Authors: Fox, Christopher B.1; Myers, Grant A.2; Harris, Joel M.3
Source: Applied Spectroscopy, Volume 61, Issue 5, Pages 94A-102A and 459-569 (May 2007) , pp. 465-469(5)
Publisher: Society for Applied Spectroscopy
Abstract:
Optical-trapping confocal Raman microscopy enhances the capabilities of traditional Raman spectroscopy for the analysis of small particles by significantly reducing the sampling volume and minimizing background signal from the particle surroundings. Chemical composition and structural information can be obtained from optically trapped particles in aqueous solution without the need for labeling or extensive sample preparation. In this work, the challenges of measuring temperature dependent changes in suspended particles are addressed with the development of a small-volume, thermally conductive sample cell attached to a temperature-controlled microscope stage. To demonstrate its function, the gel to liquid-crystalline phase transitions of optically trapped lipid vesicles, composed of pure 1,2-ditridecanoyl-sn-glycero-3-phosphocholine (DTPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), were detected by changes in Raman spectra of the lipid bilayer. The Raman scattering data were found to correlate well with differential scanning calorimetry (DSC) results.Keywords: CONFOCAL RAMAN MICROSCOPY; CRM; TEMPERATURE CONTROL; PHOSPHOLIPID VESICLES
Document Type: Research article
DOI: 10.1366/000370207780807786
Affiliations: 1: Department of Bioengineering, University of Utah, 50 South Central Campus Drive, Salt Lake City, Utah 84112-9202 2: Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850 3: Department of Bioengineering, University of Utah, 50 South Central Campus Drive, Salt Lake City, Utah 84112-9202; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850

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