Chemiluminescence microscopy as a tool in biomedical research

Chemiluminescence has become a standard tool in biomedical research. Chemil uminescent probes are used for immunoassays, nucleic acid identification, r eporter gene assays, measuring enzyme activity, and the detection of ions a nd small molecules such as Ca2+, ATP, NO, O-2(-), and H2O2. Along with the development of new chemiluminescent probes, significant progress has been m ade in techniques to measure chemiluminescence. Ultra-sensitive photometers or luminometers have become widely available and can be obtained with auto matic injectors and microplate readers. In addition, imaging photon detecto rs have been developed that allow the imaging of chemiluminescence from gel s, blots, and microplates. Imaging photon detectors have also been attached to microscopes and allow imaging of chemiluminescent probes and reporter g enes in cells and tissues. Specific methods of photon collection, storage, and analysis have been developed for microscopic imaging of chemiluminescen ce. Two of these methods are discussed in detail. The first is a method of data storage that allows days of continuous imaging without creating oversi zed files. The second is a method for calibrating photon imaging microscope s using a low-light standard. Such calibration will be helpful for comparin g the performance of various photon imaging systems and for comparing data obtained in different laboratories.