Chemiluminescence imaging of localized enzymes by scanning chemiluminescence microscopy

A novel scanning chemiluminescence microscopy (SCLM) was used for imaging localized horse radish peroxidase (HRP) or glucose oxidase (GOD) immobilized at a solid substrate. SCLM equips a scanning capillary tip (diameter, 1 mu m) for injecting a small amount of luminol onto the substrate to generate localized chemiluminescence. The chemiluminescense induced by the enzyme-catalyzed reaction was detected with a photon-counter. Two-demensional mapping of the photon-counting intensity against the tip position gave images indicating the activity of immobilized HRP and GOD.