Photoelectrochemical immunosensor for methylated RNA detection based on g-C3N4/CdS quantum dots heterojunction and Phos-tag-biotin

Publication date: 15 September 2017
Source:Biosensors and Bioelectronics, Volume 95
Author(s): Haiyan Wang, Qihai Zhang, Huanshun Yin, Minghui Wang, Wenjing Jiang, Shiyun Ai
N⁶-methyladenosine (m⁶A) is an enigmatic and abundant internal modification in eukaryotic messenger RNA (mRNA), which could affect various aspects of RNA metabolism and mRNA translation. Herein, a novel photoelectrochemical (PEC) immunosensor was constructed for m⁶A detection based on the inhibition of Cu²⁺ to the photoactivity of g-C3N4/CdS quantum dots (g-C3N4/CdS) heterojunction, where g-C3N4/CdS heterojunction was used as photoactive material, anti-m⁶A antibody as recognition unit for m⁶A-containing RNA, Phos-tag-biotin as link unit and avidin functionalized CuO as PEC signal indicator. When CuO was captured on electrode through biotin-avidin affinity reaction and then treated with HCl, Cu²⁺ could be released and CuxS would be formed based on the selective interaction between CdS and Cu²⁺, leading the photocurrent obviously decreased. Under the optimal detection conditions, the PEC biosensor displayed a linear range of 0.01–10nM and a low detection limit of 3.53 pM for methylated RNA determination. Furthermore, the developed method could also be used to detect the expression level of m⁶A methylated RNA in serum samples of breast cancer patient before and after operative treatment. The proposed assay strategy has a great potential for detecting the expression methylation level of RNA in real sample.

Graphical abstract

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