Chemiluminescent Detection of Horseradish Peroxidase Using an Integrated Amorphous Silicon Thin-Film Photosensor

A hydrogenated amorphous silicon p-i-n photodiode fabricated on a glass substrate is used for the integrated, real-time detection of biochemiluminescent reactions. The light emission at 425 nm resulting from the oxidation of luminol catalyzed by the enzyme horseradish peroxidase (HRP) is detected. This enzyme is commonly used as a label attached to biomolecules such as proteins and nucleic acids. In a previous publication (Pimentel, et al., 2007), HRP was detected in solution with a sensitivity of 2 nM. In this work, HRP in solution was detected with sensitivity of 10 pM. In addition, HRP adsorbed in the surface was detected with sensitivity in the range of 1 fmol·cm^-2. Antibody-antigen recognition was successfully detected using antibodies labeled with HRP.