Electrochemiluminescent assay for detection of extremely rare mutations based on ligase reaction and bead enrichment.

The detection of rare mutations is particularly essential in many areas of biomedical research. Here, we report an ultrasensitive method to detect extremely rare point mutations based on electrochemiluminescent assay. The point mutation among large excess wild-type alleles is exclusively amplified through ligase detection reaction. The products corresponding to the amplification of mutant alleles are selectively captured by magnetic beads and then labeled with electrochemiluminescent substrates. Thus, point mutations with a percentage as small as 0.01% in the DNA population can be detected by electrochemiluminescent assay. Moreover, because the electrochemiluminescent signal of the mutation is proportional to the percentage of mutant alleles in the DNA population, the percentage of mutant alleles can be roughly accessed.