A label-free hemin/G-quadruplex DNAzyme biosensor developed on electrochemically modified electrodes for detection of a HBV DNA segment

作者：Shi, Lijuan; Yu, Yanyan; Chen, Zuanguang^*; Zhang, Lin; He, Sijing; Shi, Qiujia; Yang, Hongzhi

来源：RSC Advances, 2015, 5(15): 11541-11548.

DOI：10.1039/c4ra09936b

In this work, a label-free DNAzyme biosensor was proposed for the detection of oligonucleotides related to a hepatitis B virus (HBV) DNA segment. The novel DNAzyme biosensor was based on the electrochemical reduction of graphene oxide-carboxyl multi-walled carbon nanotube composites (GO-CMWCNTs) and the electrodeposition of gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE). The thiolate hairpin capture probes with a caged G-quadruplex configuration were self-assembled on AuNPs through the well-known Au-thiol binding. Only after hybridization with target DNA, the hairpin configuration could be opened and released the particular guanine-rich nucleic acid sequences which could assemble to G-quadruplexes. In the presence of hemin and K , the hemin/G-quadruplex DNAzyme was generated on the electrode surface, triggering the electrochemical H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). With the advantages of amplification effects of AuNPs and hemin/Gquadruplex, a linear concentration range from 10 pM to 10 nM with a limit of detection of 0.5 pM was obtained for the target DNA. This method exhibited excellent discrimination of target DNA from one or two-base mismatched DNA and non-complementary DNA sequences. In addition, the proposed biosensor was successfully applied to the determination of target DNA in human serum samples.

• 出版日期2015
• 单位中山大学