A design for a real-time fluorescence polarization computer

We have developed hardware components for our flow cytometer cell sorter which can perform real-time calculations of either fluorescence polarization (FP) or anisotropy on a cell-by-cell basis and which can provide gating signals for the sorting of these cells into two populations. Artificial FP measurements, using electronic pulses varied over a 40dB range, were used to evaluate the computer's useful dynamic range. Real FP measurements, using human peripheral blood lymphocytes stimulated with phytohemagglutinin and labeled with fluorescein diacetate in saline, are presented to allow comparison with earlier work.