Scanning Near-Field Fret Microscopy

Acceptor emission is dependent on the rate of energy transfer, kj, between donor and acceptor dyes which is given by 

Striking differences exist between the fluorescence features observed in the two images, examples of which are denoted by the circled region and the features marked by 

It was reported that the high binding affinity between BPT and the immobilized antibody meant t t once bound ligand saturated the antibodies, each tip was no longer active and had to be replaced. Practically, this allowed only one run for each tip fabricated. Because of this, calibration of the sensor response had to be done with many sensors prepared under similar conditions and not wi the actual sensor used in the experiment. 

these initial proof-of-principle experiments demonstrate the ability to use the epitope specificity of antibodies to specifically detect a molecule of interest within the complex intracellular milieu of the cytoplasm, albeit with limitations. However, the small size of these probes did allow for membrane penetration within specific and distinct sub-cellular regions, which perhaps will permit differential localization of target molecules within a cell in the future. 

Typically, agents used to modify probes are selected so that their optical properties, i.e. fluorescence, are modified in the presence of a relevant ligand. Although within the fiber optic sensor field a distinction is sometimes made between sensors, which are said to detect events continuously, and probes, which are thought of as single use instruments, for clarity and simplicity, those distinctions will not be made here and the terms will be used interchangeably.(Vo-Dinh, Alarie et al. 2000) 

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