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Ultrasensitive photoelectrochemical biosensor for DNA 5-methylcytosine analysis based on co-sensitization strategy combined with bridged DNA nanoprobe

2022; Elsevier BV; Volume: 254; Linguagem: Inglês

10.1016/j.talanta.2022.124140

1873-3573

Chuiyu Zhu, Xiao Tian, Qiuyan Li, Zichang Dai, Lina Wang, Huamin Liu, Chenghong Li, Kashif Rafiq Zahid, Chunmei Wu, Hui Huang, Lichao Fang, Qiyuan Huang, Feixue Liu, Jun Deng, Yan Li, Tao Zeng, Junsong Zheng,

Advanced Photocatalysis Techniques

Altered DNA methylation in the form of 5-methylcytosine (5-mC) patterns is correlated with disease diagnosis, prognosis, and treatment response. Therefore, accurate analysis of 5-mC is of great significance for the diagnosis of diseases. Here, an efficient enhanced photoelectrochemical (PEC) biosensor was designed for the quantitative analysis of DNA 5-mC based on a cascaded energy level aligned co-sensitization strategy coupling with the bridged DNA nanoprobe (BDN). Firstly, Au nanoparticle/graphite phase carbon nitride/titanium dioxide (AuNPs/g-C3N4@TiO2) nanocomposite was synthesized through in situ growth of AuNPs on g-C3N4@TiO2 surface as a matrix to provide a stable background signal. Next, BDN with a high mass transfer rate synthesized from a pair of DNA tetrahedral as nanomechanical handles was used as a capture probe to bind to the target sequence. The polydopamine nanosphere was applied to load with CdTe QDs (PDANS-CdTe QDs) as a photocurrent label of 5-mC antibodies. When the 5-mC existed, a large number of PDANS-Ab-CdTe QDs were introduced to the electrode surface, the formed CdTe QDs/AuNPs/g-C3N4@TiO2 co-sensitive structure could effectively enhance the electron transfer capability and photocurrent response rate due to the effective cascade energy level arrangement, leading to a significantly enhanced photocurrent signal. The proposed PEC biosensor manifested a wide range from 10-17 M to 10-7 M and a detection limit of 2.2 aM. Meanwhile, the excellent performance indicated the practicability of the designed strategy, thus being capable of the clinical diagnosis of 5-mC.