title: Versatile electrochemiluminescent biosensor for protein-nucleic acid interaction based on the unique quenching effect of deoxyguanosine-5'-phosphate on electrochemiluminescence of CdTe/ZnS quantum dots.
abstract: In this paper, the efficient quenching effect of deoxyguanosine-5'-phosphate (dGMP) on anodic electrochemiluminescence (ECL) of the CdTe/ZnS quantum dots (QDs) is reported for the first time. This ECL quenching was found to be specific for free dGMP and not observed for dGMP residues in different DNA structures. The unique dGMP-based QDs ECL quenching was then utilized to develop a versatile biosensing strategy to determine various protein-DNA interactions with the assistance of exonuclease, Exo I, to hydrolyze DNA and liberate dGMP. Taking single-stranded DNA binding protein (SSB) and thrombin as examples, two novel detection modes have been developed based on dGMP-QDs ECL strategy. The first method used hairpin probes and SSB-promoted probe cleavage by Exo I for facile signal-off detection of SSB, with a wide linear range of 1-200 nM and a low detection limit of 0.1 nM. The second method exploited aptamer-thrombin binding to protect probes against Exo I degradation for sensitive signal-on detection of thrombin, giving a linear response over a range of 1-150 nM and a detection limit as low as 0.1 nM. Both methods were homogeneous and label-free without QDs or DNA modification. Therefore, this dGMP-specific QDs ECL quenching presents a promising detection mechanism suitable for probing various protein-nucleic acid interactions.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.forename: Lifen
authors.initials: L
authors.lastname: Zhou
authors.forename: Zhou
authors.initials: Z
authors.lastname: Nie
authors.forename: Xiahong
authors.initials: X
authors.lastname: Xu
authors.forename: Wang
authors.initials: W
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Kaiyu
authors.initials: K
authors.lastname: He
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry; D003848:Deoxyguanine Nucleotides / Q000032:analysis* / Q000378:metabolism; D055664:Electrochemical Techniques / Q000379:methods*; D008163:Luminescent Measurements / Q000379:methods*; D009696:Nucleic Acids / Q000032:analysis / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D045663:Quantum Dots / Q000737:chemistry*; D013691:Tellurium / Q000737:chemistry; D013917:Thrombin / Q000032:analysis* / Q000378:metabolism; D019287:Zinc Sulfate / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D003848:Deoxyguanine Nucleotides; D009696:Nucleic Acids; D019287:Zinc Sulfate; C007257:2'-deoxyguanosine 5'-phosphate; D013917:Thrombin; D013691:Tellurium; C028337:cadmium telluride