UV LED excited time gated luminescence flow cytometry: evaluation for rare event particle counting
Flow cytometric detection of specific rare event targets within high background samples such as water or food are frequently defeated by the extremely large population of non target background particles. Time gated detection of long lifetime fluorescence >10ms) labeled microbial targets has been proven highly efficient in suppressing this non target autofluorescent <0.1ms) background. A time gated luminescence (TGL) flow cytometer using UV LED excitation has demonstrated the successful detection of rare event particles in high autofluorescence background samples. In this report, high quality 5mm europium beads were made (homogenous intensity and aggregation free) for a detailed evaluation of the prototype performance. The known number of beads (10+ 2, 100+ 20 and 1000+ 100) were first sorted by a conventional flow cytometry sorter, and spiked into an environmental water concentrate (1 ml; containing >10 million non target particles) The recovery rate for counting these very rare event particles using the TGL flow cytometer was then found to be 100% 20% between bead concentrations evaluated.
SPIE BiOS