Zha, Ruyan, Wu, Ruoyu, Zong, Yuange, Wang, Zhengguo, Wu, Tsunghsueh, Zhong, Yingying, Liang, Haiping, Chen, Lifei, Li, Chunya, and Wang, Yanying
A dual-mode biosensor constructed based on photoelectrochemical (PEC) and electrochemical (EC) property was developed for assaying circulating tumor DNA (ctDNA), which is commonly used for triple-negative breast cancer diagnosis. Ionic liquid functionalized two-dimensional Nd-MOF nanosheets were successfully synthesized through a template-assisted reagent substituting reaction. Nd-MOF nanosheets integrated with gold nanoparticles (AuNPs) were able to improve photocurrent response and supply active sites for assembling sensing elements. To achieve selective detection of ctDNA, thiol-functionalized capture probes (CPs) were immobilized on the Nd-MOF@AuNPs modified glassy carbon electrode surface, thereby generating a "signal-off" photoelectrochemical biosensor for ctDNA under visible light irradiation. After the recognition of ctDNA, ferrocene-labeled signaling probes (Fc-SPs) were introduced into the biosensing interface. After hybridization between ctDNA and Fc-SPs, the oxidation peak current of Fc-SPs generated from square wave voltammetry can be employed as a "signal-on" electrochemical signal for ctDNA quantification. Under the optimized conditions, a linear relationship was obtained to the logarithm of ctDNA concentration in between 1.0 fmol L−1 to 10 nmol L−1 for the PEC model and 1.0 fmol L−1 to 1.0 nmol L−1 for the EC model. The dual-mode biosensor can provide accurate results for ctDNA assays, effectively eliminating the probable occurrence of false-positive or false-negative results in single-model assays. By switching DNA probe sequences, the proposed dual-mode biosensing platform can serve as a strategy for detecting other DNAs and possesses broad applications in bioassay and early disease diagnosis. [Display omitted] • A template-assisted reagent substituting reaction was used for synthesizing Nd-MOF nanosheets. • Ionic liquid and gold nanoparticles enhance PEC performance of Nd-MOF nanosheets based interface. • A PEC-EC dual-mode biosensor was fabricated for high-performance sensing human serum ctDNA. • The dual-model biosensor provides a criterion for mutual confirmation of the detection accuracy. • Practicability of the PEC-EC biosensor was demonstrated by assaying ctDNA in human serum samples. [ABSTRACT FROM AUTHOR]