Synchrotron radiation as a light source in confocal microscopy of biological processes

摘要

We present a novel confocal microscope using the Daresbury Synchrotron Radiation Source as its light source. The broad spectrum of synchrotron radiation in combination with the UV compatible microscope allows the extension of confocal microscopy from the visible to the UV region down to about 200 nm. It is envisaged that structures separated by about 70 nm can be resolved at a wavelength of 200 nm. In addition the tunability of synchrotron radiation affords the selective excitation of any specific fluorescent molecule at the maximum of the absorption band. This avoids the restriction of working at fixed laser lines. A further advantage of using synchrotron radiation is the realization of multi-wavelength excitation. Test results using laser systems in the visible and in the UV are presented. Fluorescence images of test targets using UV excitation reveal the superior resolution of the microscope. Furthermore images of Leydig cells incubated with a fluorescent cholesterol derivative whose maximum of absorption is at 325 nm are shown. These images cannot be produced by conventional confocal laser microscopes. Finally promising preliminary results obtained with synchrotron radiation are presented.