Fluorescence measurements on nanotiter plates

Two different highly sensitive and fast but low-cost instruments for fluore scence measurements on nanotiter plates or other high density sample arrays are presented. Both instruments use 635 nm diode lasers for the detection of Cy5 fluorescence. In the first device all cavities of the nanotiter plat e are illuminated simultaneously and the fluorescence is detected spatially resolved by a charge-coupled device camera within a few seconds. The secon d system uses an on-chip microscanner for the sequential illumination of th e samples and the fluorescence is detected by a simple photomultiplier tube . Both instruments have originally been developed for environmental analysi s by immunochemical labeling but they can also be used for other medical an d biological purposes where analyte concentrations have to be determined. ( C) 2000 American Institute of Physics. [S0034-6748(00)04305-7].