Gibberellins Detection Based on Fluorescence Images of Porous Silicon Microcavities

Gibberellins are commonly used as a plant growth regulator in crops, and their excessive use will cause certain harm to human health. Therefore, the detection of gibberellins is of great significance to food safety. In this article, a method based on porous silicon microcavity (PSMC) fluorescence images is proposed for the fast and convenient detection of gibberellins. We experimentally demonstrate that the PSMC has a stronger enhancement on the quantum dots (QDs) fluorescence than the porous silicon Bragg mirror (PSBM). A PSMC photonic crystal sensor was prepared to detect gibberellins in combination with the digital image method. The gibberellin antibody was labeled with carboxyl water-soluble CdSe/ZnS QDs as a fluorescent marker, which reacted specifically with the gibberellin antigen immobilized on the porous silicon (PS) inner wall. Finally, a digital microscope was used to capture a fluorescence image of the PSMC surface. Gibberellins were detected by calculating the average change in gray value between the images taken before and after the immunoreaction. The detection limit of the method for gibberellins is 20.05 pg/mL.