Simplified format for DNA probe-based tests

Abstract

The approach I describe to using DNA probes in diagnostic tests is simpler than most existing formats. DNA in a sample is labeled by chemical reaction with bisulfite and methylamine to generate a sulfonated derivative. The DNA need not be purified to do this. The labeled sample is then incubated with an unlabeled, purified probe DNA, which is immobilized to a solid support. The amount of label remaining on the solid support after washing is detected by a monoclonal antibody that recognizes modified cytosines. The intensity of the signal depends on the amount of target DNA in the sample. Detection limits depend on the amount of immobilized DNA and on the degree of physical entrapment of the labeled DNA in sample material, but can be as low as 5 pg. This format is well suited to automation for use with existing robotic enzyme immunoassay procedures.