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

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

来源：Talanta, 2023, 254: 124140.

DOI：10.1016/j.talanta.2022.124140

• Photoelectrochemical biosensor
• 5-Methylcytosine
• Co -sensitization strategy
• Bridged DNA nanoprobe
• AuNPs
• g-C 3 N 4 @TiO 2 nanocomposite
• PDANS-CdTe QDs conjugate

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 sur-face 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.

• 单位
  南方医科大学; 广东医学院; y