title: Designed diblock hairpin probes for the nonenzymatic and label-free detection of nucleic acid.
abstract: The detection of nucleic acid sequences is of great importance in a variety of fields. An ultrasensitive DNA sensing platform is constructed using elaborately designed diblock hairpin probes (DHPs) that are composed of hairpin and poly-adenine blocks. The introduction of an initiator DNA target triggers the catalytic assembly of probes DHP1, DHP2 and DHP3 to fabricate numerous poly-adenine-tailed branched DNA junctions, which significantly amplify the signal of the target-DNA-recognizing event without any enzyme. Coupled to a gold nanoparticle-based colorimetric assay, the amplified recognition signal can be quantitatively detected or visually read with the naked eye. The combination of the high-efficiency target-catalyzed DHP assembly and sensitive gold-based colorimetric assay offers an ultrasensitive detection of DNA with a detection limit of 0.1 pM and a dynamic range from 0.01 to 5 pM. The proposed sensing platform can discriminate even single-base mutations. Moreover, the sensing platform can be expanded to detect pollutant-degrading-bacteria-specific DNA sequences. The proposed sensing system should offer an alternative approach for the detection of nucleic acids in the fields of microbiology, biogeochemistry, and environmental sciences.
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, China; Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Junlin
authors.initials: J
authors.lastname: Wen
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China. Electronic address: jhchen@soil.gd.cn.
authors.forename: Junhua
authors.initials: J
authors.lastname: Chen
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhuang
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China. Electronic address: sgzhou@soil.gd.cn.
authors.forename: Shungui
authors.initials: S
authors.lastname: Zhou
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D003124:Colorimetry / Q000379:methods*; D015342:DNA Probes / Q000737:chemistry*; D004269:DNA, Bacterial / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D020592:Shewanella / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D015342:DNA Probes; D004269:DNA, Bacterial; D006046:Gold
keywords: Branched DNA junction; Catalytic hairpin assembly; Colorimetric assay; Gold nanoparticles; Shewanella oneidensis