APPARATUS AND METHODS FOR FLOW PHOTOMETRY OF PARTICLES OF A DISPERSION

• US 3,738,759 A
• Filed: 04/16/1970
• Issued: 06/12/1973
• Est. Priority Date: 04/18/1969
• Status: Expired due to Term

• Current Assignee: Wolfgang Dittrich, Wolfgang Gohde
• Original Assignee: Wolfgang Dittrich, Wolfgang Gohde
• Inventors: Dittrich, Wolfgang, Gohde, Wolfgang
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Evans, F. L.
• Application Number:
  US05/029,215
• Time in Patent Office: 1,153 Days
• Field of Search: 356/102,103,207,208,36,39,244,246 250/218,222PC
• US Class Current: 356/442
• CPC Class Codes: G01N 15/1404 Handling flow, e.g. hydrodynamic focusing
• CPC Class Codes: G01N 21/6458 Fluorescence microscopy fluorescence microscopes per se G02B21/0076 and G02B21/16
• CPC Class Codes: G01N 21/6486 Measuring fluorescence of biological material, e.g. DNA, RNA, cells G01N21/6428 takes precedence
• CPC Class Codes: G06M 1/101 by electro-optical means

Abstract

In flow photometry by means of transmitting light from a light source to a flowing dispersion in a measuring zone and from the dispersion to a photosensitive receiver and associated apparatus for measuring and/or counting the particles of the dispersion and in which there is an optical axis extending from the measuring zone to the photosensitive receiver, the improvements in which the dispersion is caused to flow through the measuring zone with a velocity component parallel to the optical axis, and a stream of the dispersion medium optically empty or other optically empty fluid of like refractive index is directed to wash the dispersion from the measuring zone or to form an envelope around the dispersion as the dispersion is introduced into the measuring zone.

Claims

1. A method of flow photometry of particles of a fluid dispersion comprising:

focusing a beam of light to a focal plane of microscopic depth to homogeneously illuminate a measuring region within said focal plane;

passing a particle carrying first fluid dispersion through said plane in a direction having a component perpendicular to said focal plane;

continuously passing a second fluid past the focal plane in a direction to wash the dispersion from said focal plane;

directing light emanating from particles only in said focal plane to a photodetector; and

analyzing a characteristic of the dispersion using the information derived from the photodetector.

2. A method according to claim 1, further including forming an envelope of a third fluid about the dispersion as it is passed into said measuring region.

3. A method of flow photometry of particles of a fluid dispersion comprising:

focusing a beam of light to a focal plane of microscopic depth to homogeneously illuminate a measuring region within said focal plane;

passing a particle carrying first fluid dispersion through said plane in a direction having a component perpendicular to said focal plane;

forming an envelope of a second fluid about the dispersion as it is passed into the measuring region;

directing light emanating from particles only in said focal plane to a photodetector;

an analyzing a characteristic of the dispersion using the information derived from the photodetector.

4. An apparatus for flow photometry of microscopic particles in a fluid dispersion comprising the combination of:

a flow chamber having a transparent wall;

a light source;

an optical system including means for focusing a beam of light to a focal plane of microscopic depth within said chamber to homogeneously illuminate a measuring region within said focal plane, and means for detecting light emanating only from particles passing through said focal plane and for producing a signal usable to analyze a characteristic of said dispersion;

means for conducting a first fluid dispersion current through said focal plane with a velocity component normal to said focal plane; and

means for continuously conducting a second fluid past said focal plane to remove particles which have passed through said focal plane.

5. Apparatus according to claim 4 wherein said means for conducting a fluid dispersion includes first and second tubes having concentric end portions, said first tube being within said second tube and carrying the dispersion current in the direction of the focal plane, and said second tube providing an enveloping current of fluid around said dispersion as said particles move through said focal plane.

6. An apparatus for flow photometry of microscopic particles in a fluid dispersion comprising the combination of:

a flow chamber having at least one transparent wall and filled with fluid;

a light source;

an optical system including means for focusing a beam of light to a focal plane of microscopic depth within said chamber to homogeneously illuminate a measuring region within said focal plane, and means for detecting light emanating only from particles passing through said focal plane and for producing a signal usable to analyze a characteristic of said dispersion; and

means for conducting a fluid dispersion current through said focal plane with a velocity component normal to said focal plane, wherein said means for conducting a fluid dispersion includes a first tube having an end spaced from said focal plane for conducting an enveloping fluid, a second tube located within said first tube and having an end spaced from said focal plane for directing a dispersion current towards said focal plane said first tube providing an enveloping current of fluid around said dispersion current as said particles approach said focal plane, and a third tube to permit said fluids to leave said chamber.