USE OF A SPHERICAL MULTIPARAMETER TRANSDUCER FOR FLOW-CYTOMETRY

Fused silicon dioxide, multiparameter now transducers with 50 mu m internal square cross section and similar to 60 mu m length can simultaneously measure DC and RF impedance as well as fluorescence and multiple-angle Light scattering, A spherical version of such a transducer was mounted in an EPICS CVA flow-cell housing and was installed on a research prototype equipped with an argon-ion laser, The signal that was produced by the spherical transducer with EPICS DNA-Check beads was 1.73 times greater than that produced with the standard cylindrical now cell, Similarly, with EPICS Immuno-Brite beads, the average ratio was 1.96. The Coulter impedance and light-scattering measurements were similar to those produced with the conventional cylindrical outside now cell, although the internal cross section of the sphere was square and that of the cylinder was circular, The theoretical arguments of Leif and Wells have been demonstrated to be correct, At present, monolithic, spherical fused-silica transducers are the optimal design for combined electrooptical, multiparameter now cytometry analyzers. (C) 1995 Wiley-Liss, Inc.