Articles & Tech Notes

BennuBio instruments take the power of flow cytometry and increase it by 10-fold. This is achieved using acoustic standing waves to generate parallel sample streams in a large flow cell that also allows analysis of particles up to 1000 µm in diameter. No hydrodynamic focusing is required, so samples are not diluted during analysis and the complete sample can be recovered intact. Our optical system identifies the events in each stream to achieve analytical rates that are 10x faster than the fastest flow cytometer at the same coincidence rate. Our flow cell allows sample flow rates thousands of times faster than a conventional instrument, opening flow cytometry up to analysis of large volume samples.

BennuBio Tech Note

tech note screenshotVelocyt Large Particle Flow Cytometer

Flow cytometry has long been the standard for many forms of cellular analysis. However, traditional flow cytometry only analyzes one cell stream at an analysis rate of <50K particles/sec and a sample volumetric rate of <250 μL/min. This limitation makes traditional flow cytometers poorly suited for rare cell analysis in high cellular backgrounds, detection of cells/particles in large dilute samples, or rapid analysis of diluted blood samples. In addition, traditional flow cytometers cannot perform analysis of spheroid and organoid models critical to immunology and oncology research, drug screening and clinical applications in oncology, transplantation and artificial organs.

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Parallel Streams

The Velocyt uses a patented system to generate parallel flow streams with acoustic standing waves and simple laminar flow through the flow cell

  • Acoustic standing waves are driven at megahertz frequencies in a flow channel that has acoustically reflective walls.
  • This acoustic force drives particles that have higher density and that are less compressible than the surrounding fluid to the “pressure nodes”.
  • The frequency of the standing waves can be set such that a known number of streams is generated across the channel.
  • Vertical positioning is achieved using wide shallow channels that enable the lift forces generated by flowing fluid to move particles into a vertically centered position.
  • Particles flow through one or more optical sensing regions by simply pumping the complete sample through the flow cell.

Large Particle Analysis

The use of channels up to 1 mm in height and 14 mm in width will accommodate particles as large as ~1,000 µm in diameter. Combined with our multistream detection approach, this enables large particle analysis more efficiently and at higher spatial resolution than any other flow cytometer.

Total Sample Recovery

Our acoustic focusing approach does not require sheath fluid, which enables recovery of the unaltered sample. Our high flow rates allow analysis of your entire sample, which is returned to you intact. This is extremely valuable for samples that are costly, otherwise precious or needed for off-line analysis. This also makes the Velocyt the only flow cytometer capable of simple kinetic analysis of the same, unaltered sample.

Correlated Optical Detection

Our patented fluidic approach is coupled with a patented approach to optical interrogation. A line focused laser illuminates across all streams, which constrains the illumination to reduce background while providing sufficient power for resolving dim particles. An extremely fast sCMOS camera images the laser intersection region(s) to record scatter and fluorescence signals from each focused stream simultaneously.

Simple Data Acquisition

Images for each stream are processed into signal pulses and standard flow cytometry parameters are extracted (signal height, width, area, ToF). Data from all streams are integrated into a single data file containing all events, displayed with a custom user interface and available as standard FCS files.

Very High Analysis Rates/Volumes

Having 10 or more simultaneous analysis regions increases the analysis rate to at least 10x that of a conventional flow cytometer without raising the coincidence rate. Our large flow cell can operate up to 10’s of mL/min, for the first time opening flow cytometry to analysis of very large numbers of cells and/or very large samples in a short period.

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