title: A label-free colorimetric isothermal cascade amplification for the detection of disease-related nucleic acids based on double-hairpin molecular beacon.
abstract: K-Ras mutations at codon 12 play an important role in an early step of carcinogenesis. Here, a label-free colorimetric isothermal cascade amplification for ultrasensitive and specific detection of K-Ras point mutation is developed based on a double-hairpin molecular beacon (DHMB). The biosensor consists of DHMB probe and a primer-incorporated polymerization template (PPT) designed partly complementary to DHMB. In the presence of polymerase, target DNA is designed to trigger strand displacement amplification (SDA) via promote the hybridization of PPT with DHMB and subsequently initiates cascade amplification process with the help of the nicking endonuclease. During the hybridization and enzymatic reaction, G-quadruplex/hemin DNAzymes are generated, catalyzing the oxidation of ABTS2-by H2O2in the presence of hemin. Utilizing the proposed facile colorimetric scheme, the target DNA can be quantified down to 4 pM with the dynamic response range of 5 orders of magnitude, indicating the substantially improved detection capability. Even more strikingly, point mutation in K-ras gene can be readily observed by the naked eye without the need for the labeling or expensive equipment. Given the high-performance for K-Ras analysis, the enhanced signal transduction capability associated with double-hairpin structure of DHMB provides a novel rout to screen biomarkers, and the descripted colorimetric biosensor seems to hold great promise for diagnostic applications of genetic diseases.
authors.affiliation: Cancer Metastasis Alert and Prevention Center, Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, College of Chemistry, Fuzhou University, Fuzhou, 350002, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wu
authors.affiliation: Cancer Metastasis Alert and Prevention Center, Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, College of Chemistry, Fuzhou University, Fuzhou, 350002, China.
authors.forename: Huo
authors.initials: H
authors.lastname: Xu
authors.affiliation: Cancer Metastasis Alert and Prevention Center, Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, College of Chemistry, Fuzhou University, Fuzhou, 350002, China.
authors.forename: Haimei
authors.initials: H
authors.lastname: Shi
authors.affiliation: Cancer Metastasis Alert and Prevention Center, Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, College of Chemistry, Fuzhou University, Fuzhou, 350002, China.
authors.forename: Weihong
authors.initials: W
authors.lastname: Li
authors.affiliation: Cancer Metastasis Alert and Prevention Center, Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, College of Chemistry, Fuzhou University, Fuzhou, 350002, China.
authors.forename: Mengze
authors.initials: M
authors.lastname: Sun
authors.affiliation: Cancer Metastasis Alert and Prevention Center, Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, College of Chemistry, Fuzhou University, Fuzhou, 350002, China. Electronic address: wuzaisheng@163.com.
authors.forename: Zai-Sheng
authors.initials: ZS
authors.lastname: Wu
mesh_terms: D015374:Biosensing Techniques; D003124:Colorimetry; D004252:DNA Mutational Analysis; D021881:DNA, Catalytic; D011905:Genes, ras; D006801:Humans; D006861:Hydrogen Peroxide; D057230:Limit of Detection; D021141:Nucleic Acid Amplification Techniques; D009690:Nucleic Acid Conformation; D017354:Point Mutation
chemical_list: D021881:DNA, Catalytic; D006861:Hydrogen Peroxide
keywords: Double-hairpin molecular beacon (DHMB); Isothermal cascade amplification; K-Ras gene