Evaluation of primary DNA-damage is one way to identify potential genotoxic 
agents and for this purpose the Comet assay has, for the last decades, been used 
to monitor DNA single strand and double strand breaks in individual cells. 
Various attempts have been made to modify the different steps in the in vitro 
protocol for the Comet assay in order to improve its sensitivity. However, to 
the best of our knowledge, nobody has tried to replace the traditionally used 
NaOH-based electrophoresis solution (pH > 13), with another type of solution. In 
the present paper, using TK-6 cells exposed to different concentrations of H2O2 
or ionizing radiation, we present evidence clearly showing that a low-conductive 
LiOH-based electrophoresis solution at pH 12.5, and a more gentle lysis 
procedure, significantly improved both the speed and sensitivity of the assay. 
The new approach, which we call the Flash-comet, is based on a lysis buffer at 
pH 8.5, an unwinding time of 2.5 min in a LiOH solution without EDTA at pH 12.5, 
and an electrophoresis time of 1 min at 150 V (5 V/cm) using the same solution.