The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 27, 1994
Filed:
Sep. 27, 1993
Timothy C Fisher, Pasadena, CA (US);
Other;
Abstract
An apparatus and method for counting and measuring the size of particles, particularly in the range 10 nanometers to 10 micrometers in diameter, and for measuring both the size and deformability of deformable particles, primarily red and white blood cells, in which are provided, in combination: --a membrane 10 containing multiple apertures 12 providing the only means of continuity between two fluid reservoirs 16 and 18; electrodes 20 and 22 mounted one in each reservoir; and another electrode 14 situated inside each aperture, forming part of the wall. The position of electrode 14 effectively divides the aperture into two aperture regions 28 and 30 having similar electrical resistance. In use, a conductive fluid containing the particles is placed into reservoir 16 and aspirated through the apertures into reservoir 18. A voltage V.sub.in applied between electrodes 20 and 22, causes a corresponding voltage V.sub.out at each electrode 14. Particles entering an aperture increase the resistance of first one aperture portion and then the other, producing a biphasic fluctuation in V.sub.out, the magnitude of which indicates the particle size. If one of the aperture portions 28 is made smaller than a deformable particle, e.g. a red blood cell, then the duration of the corresponding phase of the signal reflects the deformability of the cell, while the cell size is given by the magnitude of the other phase. The physical and electrical independence of the multiple apertures permits high data acquisition rates, sophisticated noise reduction, and other significant advantages which facilitate the measurement of very small particles.