title: A TdT-mediated cascade signal amplification strategy based on dendritic DNA matrix for label-free multifunctional electrochemical biosensing.
abstract: We describe a novel label-free amplified multifunctional strategy of dendritic electrochemical DNA sensor based on terminal deoxynucleotidyl transferase (TdT). We have found that the sequence composition of TdT-yielded DNA is largely dependent on the constitution of substrate deoxynucleotides (dNTPs) pool. After rational design of dNTPs pool and controllable TdT polymerization, dendritic protocol has been developed involving two-type amplification strategies; one is the formation of "trunk" and "branch" of the dendritic electrochemical sensor by TdT amplification; the other is the introduction of nucleic acid functionalized Au nanoparticles (DNA-AuNPs) for multiple branching. The results indicate that the G-rich ssDNA, which is synthesized under the condition of 40% deoxyadenosine triphosphate (dATP) and 60% deoxyguanosine triphosphate (dGTP), can be induced to form a long signal strand to G-quadruples (G4) in the presence of Pb(2+). The electrochemical sensing platform is employed for sequence-specific DNA detection and the detection limit is as low as 1 fM. Our multifunctional strategy is further extended to Pb(2+) detection and thrombin aptasensor. This proposed sensor displays excellent sensitivity and selectivity, and is applied for detection in complicated samples successfully.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Yufang
authors.initials: Y
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Qinpeng
authors.initials: Q
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Wang
authors.initials: W
authors.lastname: Li
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Zhuoliang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China. Electronic address: niezhou.hnu@gmail.com.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Nie
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D015374:Biosensing Techniques; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification*; D004253:DNA Nucleotidylexotransferase / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*
chemical_list: D006046:Gold; D004247:DNA; D004253:DNA Nucleotidylexotransferase
keywords: Dendritic DNA matrix; Label-free; Multifunctional electrochemical sensor; Nucleic acid functionalized Au nanoparticles; TdT-mediated cascade signal amplification