Near-Field Spectroscopy

To study single biomolecule dynamics we have developed near-field spectroscopy.  In near-field spectroscopy information is obtained using spectroscopic techniques rather than imaging.  The near-field probe, placed over the molecule of interest, illuminates a sub-wavelength area of the sample which enables spectroscopic studies of proteins in high density in vivo or in situ  situations.  Detecting the emission of a dye molecule or the intrinsic fluorescence of the protein of interest can yield conformational information.  The potential of near-field spectroscopy lies in applying traditional far-field spectroscopic techniques to the study of single biomolecules.

Initial experiments will focus on the problem of actin-myosin binding.  As a preliminary step towards this goal, we have imaged polymerized actin labeled with TRITC phalloidin (Figure 4).

 

Figure 4. False color NSOM fluorescence image of TRITC phalloidin labeled F-actin fixed to glass, cross linked with glutaraldehyde, and air dried.  Resolution is ~200 nm (limited by tip size).
 

Scanning in Solution