Multicomponent Cu@Cu2O@C hybrid-induced photocurrent polarity switching biosensing strategy for the detection of TK1 mRNA

Thymidine kinase 1 messenger RNA (TK1 mRNA) is an attractive biomarker that plays an important role in the cancer diagnosis and prognostic treatment. Herein, an ultrasensitive and selectivity photoelectrochemical (PEC) biosensor is proposed for TK1 mRNA detection based on the multicomponent Cu@Cu 2 O@C hybrid-induced photocurrent polarity switching of titanium dioxide nanoparticles (TiO 2 NPs). The multicomponent Cu@Cu 2 O@C hybrid with porous structure and specific surface area is successfully synthesized through the carbonization of copper metal organic frameworks (Cu-MOFs) in a nitrogen atmosphere, followed by the spontaneous oxidation of Cu. Through the TK1 mRNA-mediated chain displacement reaction, the Cu@Cu 2 O@C hybrid is introduced into the TiO 2 NPs-modified electrode surface, resulting in the photocurrent polarity switching from anodic to cathodic photocurrents. Originating from high porosity, specific surface area, multicomponent synergistic effect, and efficient photocurrent-polarity-switching capability of the Cu@Cu 2 O@C hybrid, the constructed PEC biosensor for TK1 mRNA detection shows a wide linear range (1–5000 fM) with a lower detection limit (0.59 fM), and excellent anti-interference ability. Furthermore, the designed multicomponent Cu@Cu 2 O@C hybrid serves as an excellent photocurrent polarity switcher for constructing a PEC biosensor, and may have great potential in biological analysis and clinical diagnosis. • Cu@Cu 2 O@C hybrid was designed as an excellent multicomponent photocurrent-polarity switcher. • An ultrasensitive photoelectrochemical biosensing strategy was proposed for the detection of TK1 mRNA. • The anti-interference photocurrent polarity switching strategy could eliminate false positive or negative results.