One step closer to early cancer diagnosis

The research team of Professor Na Sung Soo has developed an ultra-sensitive technique for the detection of circulating tumor DNA.

The research team of Professor Na Sung Soo (corresponding author) and Chanho Park (primary author, doctorate course) at KU’s College of Engineering, Department of Mechanical Engineering has been successful in developing a technique to detect circulating tumor DNA (ctDNA).

ctDNA is a mutant form of DNA present in the blood of a cancer patient. For the early detection of cancer, it is very important to conduct highly sensitive tests. This mutant DNA must be identified with great specificity or high selectivity because its nucleotide sequence is very similar to the normal DNA circulating in the blood of people in general. In addition, in order to diagnose cancer early, it is necessary to detect the mutant DNA at a very low concentration. To accomplish this, the research team amplified the detection signal by causing a catalytic reaction of the DNA, and thereby also achieved high selectivity in their results. Therefore, detection was possible at a low concentration of 7.7 fM, a level which enables early diagnosis of cancer.

▲ Professor Na Sung Soo (left) and Chanho Park (right)

High sensitivity and selectivity testing is possible through observation of the catalytic reaction of DNA and the colorimetric detection of gold micro particles. Through the reactions of the strands of DNA being tested and the resulting color change of the gold micro particles, the research team was successful in detecting circulating tumor DNAs, enabling them to take a step closer to early cancer diagnosis.
*Colorimetric Detection Method: A method of coloring a sample solution whose characteristics are unknown and a base standard solution by adding a suitable reagent to them, and comparing the concentrations and the color tones of the sample and the base solutions in terms of the reflected light from each, in order to assess and quantify the sample. Also called colorimetric analysis.

The study was published online in the well-known international journal "Sensors and actuators B: Chemical" in February 2018. 
* Paper Title: Target Switching Catalytic Hairpin Assembly and Gold Nanoparticle Colorimetric Use for EGFR Mutant Detection

[Circulating tumor DNA detection]

The study was supported by the ERC ' Nano-Biofluignostic Research Center', Korea Research Foundation Leading Research Center.