Mapping spatial

Many years have passed since the early days of AFM, when adhesion was seen as a hindrance, and it is now regarded as a useful parameter for identification of material as well as a key to understanding many important processes in biological function. In this area, the ability of AFM to map spatial variations of adhesion has not yet been fully exploited but in future could prove to be particularly useful. At present, the chemical nature and interaction area of the AFM probe are still rarely characterized to a desirable level. This may be improved dramatically by the use of nanotubes, carbon or otherwise, with functionalized end groups. However, reliance on other measurement techniques, such as transmission electron microscopy and field ion microscopy, will probably be essential in order to fully evaluate the tip-sample systems under investigation. 

Fig.5 Schematic presentation of the STM experiment. The tunneling current is utilized for distance control of an electrode above the sample surface and maps spatially resolved the geometric and electronic properties of surfaces...

The use of SECMID to map spatial variations in the adsorption/desorp-tion characteristics of a substrate has not yet been attempted. In principle, however, it should be possible to correlate adsorption/desorption kinetics with surface structural features, using the imaging capabilities of SECM. 

Dong, M., Xu, X., BaU, A. M., Makhotd, J. A., Lam, P. C. H., Pinon, D. I., etal. (2012). Mapping spatial approximations between the amino terminus of secretin and each of the extraceUular loops of its receptor using cysteine trapping. The FASEB Journal, 26(12), 5092—5105. Retrieved from, http //www.hubmed.org/display.cgi uids=22964305. 

In FLIM, the nanosecond decay kinetics of the electronic excited state of fluo-rophores such as mCitrine, characterized by the fluorescence lifetime "t," are mapped spatially using a microscope equipped with a detector capable of... 

Modestov, A.D., Srebnik, S., Lev, O., Gun, J. (2001) Scanning Capillary Microscopy/Mass Spectrometry for Mapping Spatial Electrochemical Activity of Electrodes. Anal. Chem. 73 4229-4240. 

An AFM probe equipped with a thermal probe heats up sample resulting topographical imaging and thermal analysis of specific areas of the sample surface, sudden change in deflection of the heated cantilever indicates a thermeil transition Hme-of-flight secondary ion mass spectrometry (ToF-SIMS) Mass spectrometry of sample surface maps spatial compositional information the distribution of compounds within 1-2 nm depth... 

Scanning Auger Microscopy (SAM) is the scanning form of AES, i.e. the highly focused 5-30-keV electron beam is scanned across the surface as this allows for the lateral distribution of elements present on the surface to be mapped. Spatial resolution can extend to 10 nm or better. AES is similar to XPS in that both provide similar information using similar instrumentation. The primary difference lies in the fact that AES provides a superior spatial resolution, but at the cost of sensitivity (the sensitivity of XPS is slightly better). 

Shear force constant distance scanning potentiometry has been employed to map the dissolution of calcite crystals and shells [74] and to map spatial variations in pH at high resolution over complex microcavity-pattemed substrates [75]. The ability to approach capillaries very close to a surface, using shear force feedback, was also used for the local deposition of silver microstructures on conducting surfaces using potential-assisted ion transfer at the tip of a micropipette [76]. 

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