title: Ultrasensitive colorimetric detection of circulating tumor DNA using hybridization chain reaction and the pivot of triplex DNA.
abstract: This work presents an amplified colorimetric biosensor for circulating tumor DNA (ctDNA), which associates the hybridization chain reaction (HCR) amplification with G-Quadruplex DNAzymes activity through triplex DNA formation. In the presence of ctDNA, HCR occurs. The resulting HCR products are specially recognized by one sequence to include one GGG repeat and the other containing three GGG repeats, through the synergetic effect of triplex DNA and asymmetrically split G-Quadruplex forming. Such design takes advantage of the amplification property of HCR and the high peroxidase-like catalytic activity of asymmetrically split G-Quadruplex DNAzymes by means of triplex DNA formation, which produces color signals in the presence of ctDNA. Nevertheless, in the absence of ctDNA, no HCR happens. Thus, no triplex DNA and G-Quadruplex structure is formed, producing a negligible background. The colorimetric sensing platform is successfully applied in complex biological environments such as human blood plasma for ctDNA detection, with a detection limit corresponding to 0.1 pM. This study unambiguously uses triplex DNA forming as the pivot to integrate nucleic acid amplification and DNAzymes for producing a highly sensitive signal with low background.
authors.affiliation: School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
authors.forename: Ruimin
authors.initials: R
authors.lastname: Li
authors.affiliation: School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Zou
authors.affiliation: School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
authors.forename: Yanwei
authors.initials: Y
authors.lastname: Luo
authors.affiliation: School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
authors.forename: Manjun
authors.initials: M
authors.lastname: Zhang
authors.affiliation: School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
authors.forename: Liansheng
authors.initials: L
authors.lastname: Ling
mesh_terms: D000074141:Circulating Tumor DNA / Q000097:blood*; D003124:Colorimetry / Q000379:methods; D004247:DNA / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000097:blood*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D000074141:Circulating Tumor DNA; C051802:triplex DNA; D004247:DNA