News Column

"Imaging Microviscometer" in Patent Application Approval Process

September 11, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventors Lewis, Neil E. (Brookeville, MD); Haber, Kenneth (Frederick, MD), filed on March 15, 2013, was made available online on August 28, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application has not been assigned to a company or institution.

The following quote was obtained by the news editors from the background information supplied by the inventors: "Lensless microfluidic detection techniques have been proposed to acquire microscopic images of samples such as biological materials and cells. They operate by acquiring images of suspended samples in close proximity to a high-resolution imaging detector. Their small size has resulted in their use being proposed in a variety of life science applications, including microscopes, smart petri dishes, and point-of-care diagnostic systems."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "In one general aspect, the invention features a capillary viscometer that includes a source of fluid pressure, a pressure transducer responsive to the source of fluid pressure, and a first capillary tube having an inside volume that is hydraulically responsive to the source of fluid pressure. A two-dimensional array of optical detectors is positioned proximate the first capillary tube with a first plurality of its detectors optically responsive to the inside volume of the first capillary tube and including an image data output. An acquisition driver circuit is responsive to the image data output of the two-dimensional array to acquire a series of successive images of the inside volume of the first capillary tube. Viscosity computation logic is responsive to the acquisition driver circuit and the pressure transducer, and operative to compute the viscosity of the fluid from pressure values received from the pressure transducer and the succession of images of the inside volume of the first capillary tube.

"In preferred embodiments, the viscosity computation logic can be responsive to the pressure transducer and be operative to compute a pressure-corrected viscosity. The apparatus can further include viscosity value selection logic responsive to the pressure transducer and with the viscosity value selection logic being operative to select a viscosity value based on detected pressure levels. The viscosity value selection logic can be operative to exclude outliers. The viscosity value selection logic can be operative to seek stable periods. The apparatus can further include a second capillary tube having an inside volume responsive to the source of fluid pressure, with the inside volume of the first capillary tube being larger than the inside volume of the second capillary tube, with the two-dimensional array of optical detectors also being positioned proximate the second capillary tube with a second plurality of its detectors optically responsive to the inside volume of the second capillary tube, and the apparatus can further include shear rate computation logic responsive to the acquisition driver circuit and operative to compute the viscosity of the fluid from the succession of images of the inside volume of the first and second capillary tubes. The apparatus can further include capillary tubes each having an inside volume responsive to the source of fluid pressure, with the inside volumes of the first capillary tube and the further tubes all being different from each other, with the two-dimensional array of optical detectors also being positioned proximate the further capillary tubes with further pluralities of its detectors each being optically responsive to the inside volumes of one the further capillary tubes, and the apparatus can further include shear rate computation logic responsive to the acquisition driver circuit and operative to compute a shear rate of the fluid from the succession of images of the inside volumes of the first capillary tube and the further capillary tubes. The first and further capillary tubes can be placed side-by-side where they are proximate the two-dimensional array of optical detectors, and are bundled at an open end. The viscosity computation logic can be operative to compute the viscosity based on detected movement of a meniscus in the first capillary tube. The viscosity computation logic can be operative to compute the viscosity based on a pixel size and frame rate. The apparatus can further include calibration storage for calibration information about a calibration run with a calibration standard, with the viscosity computation logic being responsive to the calibration information stored in the calibration storage. The apparatus can further include at least one calibration tube having an inside volume that is hydraulically responsive to at least one source of a known fluid standard with the two-dimensional array of optical detectors including a plurality of its detectors that are optically responsive to the inside volume of the calibration tube. The first capillary tube can have a diameter below about 500 microns. The two-dimensional array of optical detectors can be a two-dimensional array of visible light detectors. The two-dimensional array of optical detectors can be a two-dimensional array of infrared light detectors. The two-dimensional array of optical detectors can be a two-dimensional array of ultraviolet light detectors. The apparatus can further include a filter positioned in an optical path between the first capillary tube and the two-dimensional array of optical detectors. The filter is can be a variable filter, and the apparatus can further include spectrum derivation logic responsive to the two-dimensional array of optical detectors. The filter can be a bandpass filter.

"In another general aspect, the invention features a capillary viscometry method, which includes driving a fluid under test through an inside volume of a first capillary tube, acquiring a succession of pressure values for the fluid under test, acquiring successive images of the fluid under test as it advances through the inside volume of the first capillary tube, and deriving a viscosity of the fluid under test from the succession of pressure values and the successive acquired images of the fluid under test as it advances through the inside volume of the first capillary tube.

"In preferred embodiments, the steps of acquiring pressure values and acquiring images can take place substantially synchronously. The method can further include the steps of driving the fluid under test through an inside volume of one or more further capillary tubes, acquiring successive images of the fluid under test as it advances through the inside volume of the first capillary tube and the inside volumes of the further capillary tubes, and deriving a shear rate of the fluid from the succession of images of the inside volumes of the first capillary tube and the further capillary tubes. The step of deriving a viscosity is operative to derive a viscosity of a sample of less than 10 microliters. The method can further include the step of recovering the fluid under test from the first capillary tube after the step of acquiring. The method can further include the following calibration steps performed before the step of driving a fluid under test through the inside volume of the first capillary tube: driving a fluid calibration standard through an inside volume of a the capillary tube, acquiring successive images of the fluid calibration standard under test as it advances through the inside volume of the first capillary tube, and deriving calibration information from the successive acquired images of the fluid calibration standard as it advances through the inside volume of the first capillary tube, with the step of deriving a viscosity of the fluid under test deriving the viscosity of the fluid under test from calibration information and the successive acquired images of the fluid under test as it advances through the inside volume of the first capillary tube. The step of deriving a viscosity can be operative to derive a viscosity of a sample of less than 10 microliters. The method can further include the step of introducing a dye in the fluid under test, with the step of acquiring successive images of the fluid under test as it advances through the inside volume of the first capillary tube being sensitive to the dye. The method can further include the step of deriving a spectrum of the fluid under test as it advances through the inside volume of the first capillary tube.

"In a further general aspect, the invention features a capillary viscometer, which includes means for driving a fluid under test through an inside volume of a first capillary tube, means for acquiring a succession of pressure values for the fluid under test, means for acquiring successive images of the fluid under test as it advances through the inside volume of the first capillary tube, and means for deriving a viscosity of the fluid under test from the succession of pressure values and the successive acquired images of the fluid under test as it advances through the inside volume of the first capillary tube.

"Systems according to the invention can help to quickly characterize a variety of small samples of different fluid materials in research settings, such as in the discovery and manufacture of pharmaceuticals. They can also help to provide ongoing quality control and quality assurance in the manufacture of such materials.

BRIEF DESCRIPTION OF THE DRAWING

"FIG. 1 is a block diagram of an embodiment of a fluid characterization system according to the invention, showing one capillary tube in phantom,

"FIG. 2 is a block diagram of an embodiment of a high-throughput fluid characterization system according to the invention, and

"FIG. 3 is flowchart showing an illustrative method of operation for the embodiment of FIG. 2."

URL and more information on this patent application, see: Lewis, Neil E.; Haber, Kenneth. Imaging Microviscometer. Filed March 15, 2013 and posted August 28, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=7168&p=144&f=G&l=50&d=PG01&S1=20140821.PD.&OS=PD/20140821&RS=PD/20140821

Keywords for this news article include: Patents.

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Source: Politics & Government Week


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