The invention relates to a preparation method and application of a
sandwich type photoelectrochemical sensor for detecting a
prostate specific
antigen (PSA).
Nitrogen-
doped graphene quantum dots (N-GQDs) and
cadmium sulfide (CdS)
quantum dots double-sensitized
sea urchin-shaped
titanium dioxide (TiO2) are used as photoactive materials to be immobilized on the surface of the conductive glass. The compound of
electron holes (e<-> / h<+>) is effectively inhibited, a remarkable
photocurrent signal is generated, and rich functional groups are provided for immobilizing PSA antibodies. A gold-
carbon nanotube (Au / MWCNTs) nano-composite is adopted as a
label of a second
antibody, and
exciton-
plasma resonance (EPI) is generated according to different mechanisms. In the
system, Au NPs are enabled to generate surface
plasma resonance (SPR) in an optical excitation state. Along with the energy
resonance transfer (ET) process, the
photocurrent intensity is reduced to a certain extent, and the sensitivity of the sensor is improved. In addition, Au / MWCNTs have a large surface area and
biocompatibility. The loading capacity of the second
antibody is increased, due to the fact that the steric hindrance effect hinders
electron transfer, the
photocurrent is reduced, the sensitivity of the sensor is further improved,
specific detection of the
prostate specific
antigen is achieved, a novel and feasible detection method is provided for
early detection of PSA, and the
prostate specific
antigen sensor has potential application prospects in clinic.