title: Nanoprobe-Initiated Enzymatic Polymerization for Highly Sensitive Electrochemical DNA Detection.
abstract: Electrochemical DNA (E-DNA) sensors have been greatly developed and play an important role in early diagnosis of different diseases. To determine the extremely low abundance of DNA biomarkers in clinical samples, scientists are making unremitting efforts toward achieving highly sensitive and selective E-DNA sensors. Here, a novel E-DNA sensor was developed taking advantage of the signal amplification efficiency of nanoprobe-initiated enzymatic polymerization (NIEP). In the NIEP based E-DNA sensor, the capture probe DNA was thiolated at its 3'-terminal to be immobilized onto gold electrode, and the nanoprobe was fabricated by 5'-thiol-terminated signal probe DNA conjugated gold nanoparticles (AuNPs). Both of the probes could simultaneously hybridize with the target DNA to form a "sandwich" structure followed by the terminal deoxynucleotidyl transferase (TdT)-catalyzed elongation of the free 3'-terminal of DNA on the nanoprobe. During the DNA elongation, biotin labels were incorporated into the NIEP-generated long single-stranded DNA (ssDNA) tentacles, leading to specific binding of avidin modified horseradish peroxidase (Av-HRP). Since there are hundreds of DNA probes on the nanoprobe, one hybridization event would generate hundreds of long ssDNA tentacles, resulting in tens of thousands of HRP catalyzed reduction of hydrogen peroxide and sharply increasing electrochemical signals. By employing nanoprobe and TdT, it is demonstrated that the NIEP amplified E-DNA sensor has a detection limit of 10 fM and excellent differentiation ability for even single-base mismatch.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wan
authors.forename: Pengjuan
authors.initials: P
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Su
authors.affiliation: Division of Physical Biology and Bioimaging Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China.
authors.forename: Lihua
authors.initials: L
authors.lastname: Wang
authors.affiliation: Division of Physical Biology and Bioimaging Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China.
authors.forename: Dun
authors.initials: D
authors.lastname: Pan
authors.affiliation: Chemistry Department, King Saud University , Riyadh 11451, Saudi Arabia.
authors.forename: Ali
authors.initials: A
authors.lastname: Aldalbahi
authors.forename: Shulin
authors.initials: S
authors.lastname: Yang
authors.affiliation: Division of Physical Biology and Bioimaging Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Zuo
mesh_terms: D015374:Biosensing Techniques; D004247:DNA / Q000032:analysis*; D055664:Electrochemical Techniques / Q000379:methods*; D006735:Horseradish Peroxidase / Q000378:metabolism*; D053758:Nanoparticles / Q000737:chemistry*; D058105:Polymerization
chemical_list: D004247:DNA; D006735:Horseradish Peroxidase
keywords: electrochemical DNA (E-DNA) sensors; nanoprobe; signal amplification; terminal deoxynucleotidyl transferase (TdT)