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Raman microscopy has emerged as a powerful technique to characterize anisotropic materials with sub micro meter resolution. The use of polarized light allows one to obtain precise information about the local organization of the relevant molecular groups through the determination of the most probable distribution function. Such polarization analysis can be conducted under a confocal microscope, but caution must be exercised because of the use of objectives of high numerical value. The molecular orientation can be effectively correlated with the topography of the sample when atomic force microscopy experiments are conducted on the same object. In the present review paper, we present Raman imaging results that have been conducted on mesostructured polymer surfaces and on a single isolated semiconductor nanowire. [ABSTRACT FROM AUTHOR]

In this report, three kinds of scanning probe microscopy techniques, atomic force microscopy (AFM), confocal microscopy (CM), and scanning electrochemical microscopy (SECM), were used to study live cells in the physiological environment. Two model cell lines, CV-1 and COS-7, were studied. Time-lapse images were obtained with both contact and tapping mode AFM techniques. Cells were more easily scratched or moved by contact mode AFM than by tapping mode AFM. Detailed surface structures such as filamentous structures on the cell membrane can be obtained and easily discerned with tapping mode AFM. The toxicity of ferrocenemethanol (Fc) on live cells was studied by CM in reflection mode by recording the time-lapse images of controlled live cells and live cells with different Fc concentrations. No significant change in the morphology of cells was caused by Fc. Cells were imaged by SECM with Fc as the mediator at a biased potential of 0.35 V (vs. Ag/AgCl with a saturated KCl solution). Cells did not change visibly within 1 h, which indicated that SECM was a noninvasive technique and thus has a unique advantage for the study of soft cells, since the electrode scanned above the cells instead of in contact with them. Reactive oxygen species (ROS) generated by the cells were detected and images based on these chemical species were obtained. It is demonstrated that SECM can provide not only the topographical images but also the images related to the chemical or biochemical species released by the live cells. [ABSTRACT FROM AUTHOR]