Biological systems, microscopy studies

Prent, N., Cisek, R., Greenhalgh, C., Sparrow, R., Rohitlall, N., Milkereit, M. S., Green, C., and Barzda, V. 2005b. Application of nonlinear microscopy for studying the structure and dynamics in biological systems. Proc. SPIE 5971 5971061-68. 

We can rule out the possibility that the effect is due to the n-butylammonium ions. An electron micrograph of the supernatant fluid, taken under the same freeze-fracture conditions, was completely featureless. This is consistent with the thermodynamic behavior of simple n-butylammonium salt solutions their enthalpy of solution is nearly equal to zero [8] and their partial molar volumes are nearly independent of concentration [9], implying that there are no special ion-solvent effects in the system. The necessary conclusion is that the cooling rate used in our experiments, of the order of 103 K/sec, was too low to prevent a major reorganization of the microstructure. This could have serious repercussions for data taken from electron microscopy studies of biological systems, which are necessarily aqueous macroionic systems. 

The electrochemical systems studied by the fluorescence method are based upon the adsorption of lipid-hke compounds similar to the molecules that make up the cell membrane. The vast literature of methods and a variety of fluoro-phores are available for our use in the study of electrochemical systems. A brief review of the use of fluorescence microscopy in the study of biological systems is presented, because a number of the probes used for staining the biological structures are relevant for the electrochemical work presented. Moreover, the methods used in biological imaging to encourage fluorescence and to improve contrast are relevant for the work on electrode surfaces. 

ESR microscopy (at X-band) has been applied to a variety of materials including in situ studies of the oxidation of coals defects in diamonds radio-metric dosimeters polymer swelling and to the diffusion of oxygen in model biological systems. The resolution of ESR imaging depends on the field gradient and line width, and the best resolution to date from an X-band imager is 1 pm. 

In this chapter, an overview of recent advances in both Raman and CARS spectroscopy and microscopy techniques will be discussed. In addition, relevant applications of these methods to the study of various biological systems will be addressed. 

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