Using the bh DCS-120 Confocal Scanning FLIM system to record internal layers of flint stone we found round objects that perfectly resemble ancient bacteria. The objects are about 20 µm in size and display a triple-exponential fluorescence decay with components of 334 ps, 2534 ps, and 7794 ps, and amplitudes of 0.5924, 0.2534, and 0.1096, respectively. The fluorescence decay clearly differs from that of the surrounding material. The objects often appear in clusters and are found in many places and in different depth of the stone. This and the fact that the objects are very uniform in size makes us believe that we are indeed seeing fossil microorganisms. If this is correct laser-scanning FLIM microscopy of flint stone could be an intriguing technique to study ancient micro-organisms. For details, please see application note ‘FLIM Finds Fossil Micro-Organisms in Flint Stone’.
