A photoelectrochemical (PEC) detection platform was built based on the branched rutile/anatase titanium dioxide (RA-TiO 2 ) electrode. Theoretical calculations proved that the type-II band alignment of rutile and anatase could facilitate charge separation in the electrode. The self-generated electric field at the interface of two phases can enhance the electron transfer efficiency of the electrode. Carboxylated CdTe quantum dots (QDs) were applied as signal amplification factors. Without the target DNA presence, the CdTe QDs were riveted to the surface of the electrode by the hairpin probe DNA. The sensitization of CdTe QDs increased the photocurrent of the electrode significantly. When the target DNA was present, the structural changes of the hairpin probe DNA resulted in the failure of the sensitized structure. Benefiting from excellent electrode structure design and CdTe QDs sensitization strategy, the PEC assays could achieve highly sensitive and specific detection of target DNA in the range of 1 fM to 1 nM, with a detection limit of 0.23 fM. The electrode construction method proposed in this article can open a new avenue for the preparation of more efficient PEC sensing devices.
Keyphrases
- quantum dots
- circulating tumor
- sensitive detection
- cell free
- carbon nanotubes
- single molecule
- label free
- nucleic acid
- loop mediated isothermal amplification
- energy transfer
- solid state
- molecularly imprinted
- rheumatoid arthritis
- electron transfer
- circulating tumor cells
- minimally invasive
- real time pcr
- photodynamic therapy
- molecular dynamics simulations
- idiopathic pulmonary fibrosis
- simultaneous determination
- visible light