Versatile photoelectrochemical and electrochemiluminescence biosensor based on 3D CdSe QDs-DNA nanonetwork-SnO

A novel 3D CdSe quantum dots (QDs)-DNA nanonetwork was assembled to sensitize the mesoporous SnO2 photoelectrochemical (PEC) substrate, which was coupled with a biped-DNA walker multiple amplification technique to design a versatile electrochemiluminescence (ECL) and PEC biosensor for dual detection of HIV. Firstly, the photosensitive CdSe QDs and SnO2 nanoflowers have well-matched band-edge energy level, thus their complex can promote effective transfer of the photogenerated carriers, and show better PEC and ECL property. Then, a novel 3D CdSe QDs-DNA nanonetwork was assembled and loaded with a large amount of QDs, which was used as multifunctional PEC and ECL probes. Moreover, the target-triggered biped DNA walker-cascade amplification method was introduced to generate a large amount of output DNA, which was used to link numerous 3D CdSe QDs-DNA nanonetwork probes to the electrode, generating greatly amplified signals for sensitive assay of HIV. The highly photosensitive 3D CdSe QDs-DNA reticulated nanomaterials have high stability and controllability, and display significantly improved PEC and ECL signals of the biosensor. This method opened a new photoelectric nanocomposite of QDs-sensitized SnO2 nanoflower, and developed a versatile biosensing strategy using the 3D CdSe QDS DNA sensitization probes for ultra-sensitive detection of biomolecules, which is important for the early diagnosis of diseases.