Enhancement of sensitivity of fountain flow cytometry by background attenuation
AssigneeUniversity of Wyoming
InventorPaul E. Johnson
Life of this patent
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Abstract
Methods and apparatus for reducing the background light intensity measured by a Fountain Flow cytometer. One approach includes constraining an interrogated volume of the sample (e.g., by adding a light absorbing reagent to the sample or introducing a bend into a flow cell through which the sample flows). Another approach includes minimizing Raman scattering from the sample by choosing an excitation filter and an emission filter configured to narrowly encompass light at wavelengths within system excitation and emission peaks.
Claims25
An apparatus for enumerating particles in a liquid sample comprising:
- an imaging flow cytometer having a channel with an imaging end and a distal end, the imaging flow cytometer configured to flow the sample along a flow axis within the channel, the imaging flow cytometer further comprising:
- a transparent element transverse to the flow axis disposed at the imaging end of the channel;
- an illumination beam positioned to illuminate, through the transparent element, at least a portion of the sample and thereby particles in the sample;
- an imager for imaging an area in a focal plane transverse to the flow axis within the portion of the sample illuminated by the illumination beam;
- and
- a constraining mechanism for constraining an interrogated volume of the sample so that a ratio of the interrogated volume to that portion of the interrogated volume disposed between the focal plane and the transparent element is less than 20:1.
A method of identifying particles in a sample of liquid using an imaging flow cytometer, the method comprising the steps of:
- (a) flowing a sample along a flow axis in a channel of the imaging flow cytometer, the channel having a transparent element across the flow axis;
- (b) illuminating at least a portion of the sample through the transparent element with an illumination beam;
- (c) imaging a focal plane within the illuminated portion;
- and
- (d) constraining an interrogated volume of the sample so that a ratio of the interrogated volume to that portion of the interrogated volume between the focal plane and the transparent element is less than 20:1.
Dependencies are inferred from the claim text.