High sensitive and selective EGFR colorimetric detection based on gold nanoparticles and target catalytic hairpin assembly amplification

7^th Euro Biosensors and Bioelectronics Conference

July 10-11, 2017 Berlin, Germany

Sungsoo Na and Chanho Park

Korea University, South Korea

Posters & Accepted Abstracts: J Biosens Bioelectron

Abstract :

For diagnosis of cancer patients, mutational analysis is necessary. Especially, status of epidermal growth factor receptor (EGFR) mutations is very important factor of non-small cell lung cancer (NSCLC) diagnosis. Circulating cell-free tumor DNA (ctDNA) is a novel target material as a tool for liquid biopsy that monitors cancer status. In this paper, we detect EGFR mutations of ctDNAs using target-catalytic hairpin assembly (CHA) that is hybridized on gold nanoparticles (AuNPs). The detection is based on colorimetric method that occurs by the aggregation of AuNPs. In detail, three thiolated hairpin DNAs (H1, H2, and H3), catalyst DNA (C), and catalyst complementary DNA (c-C) are introduced to perform the CHA mechanism. Because the EGFR mutation DNA (target) contains very long nucleotides to detect directly, we devise catalyst and catalyst complementary DNAs. Firstly, we attached three hairpin DNAs to the AuNPs (d=20 nm) using thiol binding. We prepared C and c-C DNAs complex solution. When the target DNA is added to the solution containing C and c-C DNAs complex, target DNA displaces the C DNA from the complex. Then H1, H2, and H3 DNAs are activated in the presence of C DNAs and the hairpin DNAs are hybridized. As a consequence, AuNPs are aggregated corresponding to a red-to-blue color change. The result can be measured by naked eyes.

Biography :

Email: nass@korea.ac.kr