Raman membrane systems application

Conventionally, wide-field Raman microprobes are applied for such mappings, but, recently, confocal microscope systems have also been used (Bridges et al., 2004 Puppels et al., 1990, 1991 Schliicker et al., 2003). Confocal microscopy originated from biological applications with the goal of analysis of the insides of cells without destruction of the cell membrane. Confocal microscopy selectively rejects any information from planes closer or further from the focal plane. Confocal microscopy is a... 

The application of Raman spectroscopy to naturally occurring membranes is hindered by problems such as background luminescence, or the sheer complexity of the system. However, several groups have been able to obtain Raman spectra from natural membranes. The most extensively studied system is the membrane from human erythrocytes, commonly known as red blood cells [75-77]. Lippert et al. [75] examined the membranes from human red blood cells, which had been repeatedly washed to remove traces of fluorescent material. The Raman signatures of both protein and lipid components were observed and from the amide / (in D2O) and... 

Attention is focused on carotenoids and polyenes, which are known to be chemically very unstable as isolated entities but to acquire great stability when they are suitably surrounded by a protein cage and become the active elements in the mechanism of vision and photosynthesis. The CL dependence of the in situ Raman spectra of the carotenoids as naturally occurring pigments in bird feathers was studied by Veronelli et al. [65]. Later attention was focused on the bacterial membrane protein bacteriorhodopsin (bR). a small protein (—26,000 daltons) whose potential application in optical and electro-optical devices has been explored by many authors. The justification of such interest lies in the fact that bR contains all-/rfl/ .v retinal, which acts as a lightabsorbing center and makes bR a naturally reversible photochromic system. All-optical switching can be achieved by proper illumination of bR with yellow or blue light. 

Infrared spectroscopy has been a late addition to the spectroscopic inventory of the membrane biophysicist. The reason has been the presence of water. Biological membranes not only encompass a range of widely different molecular structures, but like most biological structures require an aqueous environment whereby water is not only the solvent of choice, but often part of the molecular structure itself. Water which does not impair spectroscopic measurements using the NMR, ESR, UV or Raman techniques is a strong infrared absorber, a fact which has precluded or severely limited the application of conventional infrared spectroscopy to the study of biological systems. 

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