Building of a three-dimensional apta-nano interface using silver nanoflower for photoelectrochemical detection of carcinoembryonic antigen

Enhancing the sensitivity of photoelectrochemical (PEC) assays poses a challenging task. This study proposes a method to improve the sensitivity of PEC assays by creating a three-dimensional (3D) apta-nano interface using silver nanoflowers (AgNFs) with a 3D flower-like structure as a substrate. The aptamer (Apt) was immobilized on the surface of the AgNF-loaded gold nanoparticles (AuNPs) through the dual action of polyA blocking and Au-S bonding. Despite using cadmium sulfide quantum dots (CdS QDs) as the sole photoactive material, the as-prepared photoelectrode still showed excellent sensitivity. Using carcinoembryonic antigen (CEA) as a model target, the variation value of photocurrent (ΔI) exhibited good linear correlation (R2 = 0.9974) with the logarithm of CEA concentration in a wide detection range from 0.001 to 100 ng mL−1, and the detection limit was as low as 0.64 pg mL−1. In the assay of CEA in 1% serum, the recoveries reached 98.70 ∼ 99.63% with a low relative standard derivation (RSD) ranging from 1.11% to 2.05%. This study introduces novel concepts for the development of PEC sensors, potentially enhancing their utility in the clinical detection of disease markers.