Patents by Inventor Sanford A. Asher

Sanford A. Asher has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20020031841
    Abstract: A novel colorimetric reagent is disclosed which can be used to sense a wide variety of analytes. The novel colorimetric reagent of the present invention is based in part on sensor devices composed of a crystalline colloidal array (CCA) polymerized in a hydrogel, in that the colorimetric reagent is obtained by preparing fragments from the polymerized crystalline colloidal array (PCCA) which are dispersed, for example, in a medium, such a solvent, or in the atmosphere. The hydrogels are characterized as being capable of shrinking and swelling in response to specific stimuli applied thereto. As the hydrogels shrink or swell, the lattice structure of the CCA embedded therein changes, thereby changing the wavelength of light diffracted by the CCA. When the PCCA fragments are in a dispersion in a medium, the diffraction from the dispersion is used to determine the concentration of analyte. The diffraction of the dispersed fragments results in essentially a powder pattern for the diffraction.
    Type: Application
    Filed: May 25, 2001
    Publication date: March 14, 2002
    Inventors: Sanford A. Asher, Chad E. Reese
  • Publication number: 20020032246
    Abstract: A method of making a novel composition of a porous medium comprising volume elements of both voids and pores wherein the voids are much larger than the mean size of the pores. The method includes a first step of preparation of a porous medium comprising solid particles the approximate size selected for the voids and pores as volume elements and a second step of removing the particles by etching out with hydrofluoric acid or other means to form a porous medium comprising both voids and pores. In another embodiment, the voids are prepared from etching out of a polymeric hydrogel silica particles which were allowed to self-assemble as a crystalline colloidal array prior to formation of the polymeric hydrogel around them, thereby forming a porous medium containing a crystalline colloidal array of voids containing aqueous solution. In another embodiment, a method of partitioning macromolecules between a solution comprising the macromolecules, and the voids and pores of a porous medium.
    Type: Application
    Filed: June 25, 1999
    Publication date: March 14, 2002
    Inventors: SANFORD A. ASHER, LEI LIU
  • Publication number: 20020008229
    Abstract: The present invention is related to photonic crystal devices that comprise novel mesoscopic periodic materials which comprise polymerized crystalline colloidal arrays (CCA) and at least one photosensitive component. Preferably, the photosensitive component is a photochromic molecule and more preferably the component is an azobenzene derivative. Methods for making these devices are also disclosed. The devices of the present invention are useful in many applications including, for example, optical switches, display devices and memory storage devices. The devices of the present invention permit the possibility to write with ultraviolet light and erase with visible light. In addition, the present invention is related to a functionalized polymerized crystalline colloidal array which preferably comprises reactive epoxide groups. The present invention is further directed to a photosensitive polymerized crystalline colloidal array.
    Type: Application
    Filed: February 23, 2001
    Publication date: January 24, 2002
    Inventors: Sanford A. Asher, Marta Kamenjicki, Igor K. Lednev, Viktor Meier
  • Publication number: 20010026946
    Abstract: Novel sensor devices composed of a crystalline colloidal array (CCA) polymerized in a hydrogel are disclosed. The hydrogels are characterized as being capable of shrinking and swelling in response to specific stimuli applied thereto. As the hydrogels shrink or swell, the lattice structure of the CCA embedded therein changes, thereby changing the wavelength of light diffracted by the CCA. Thus by monitoring the change in diffracted wavelength, the concentration of a stimulus is determined. The gels can be modified to sense numerous different stimuli. The sensor devices are specific in that they are modified to react with only one species or family of species. These sensors have various applications in areas including, for example, environmental and chemical systems, chemomechanical systems, sensor devices and medical diagnostic tools. Various methods for making and using these devices are also disclosed.
    Type: Application
    Filed: January 3, 2001
    Publication date: October 4, 2001
    Inventor: Sanford A. Asher
  • Patent number: 6187599
    Abstract: Novel sensor devices composed of a crystalline colloidal array (CCA) polymerized in a hydrogel are disclosed. The hydrogels are characterized as being capable of shrinking and swelling in response to specific stimuli applied thereto. As the hydrogels shrink or swell, the lattice structure of the CCA embedded therein changes, thereby changing the wavelength of light diffracted by the CCA. Thus by monitoring the change in diffracted wavelength, the concentration of a stimulus is determined. The gels can be modified to sense numerous different stimuli. The sensor devices are specific in that they are modified to react with only one species or family of species. These sensors have various applications in areas including, for example, environmental and chemical systems, chemomechanical systems, sensor devices and medical diagnostic tools. Various methods for making and using these devices are also disclosed.
    Type: Grant
    Filed: July 7, 1998
    Date of Patent: February 13, 2001
    Assignee: University of Pittsburgh
    Inventors: Sanford A. Asher, John H. Holtz
  • Patent number: 6165389
    Abstract: Devices that comprise novel, mesoscopically periodic materials that combine crystalline colloidal array (CCA) self-assembly with the temperature induced volume phase transitions of various materials, preferably poly(N-isopropylacrylamide) (PNIPAM) are disclosed. In one embodiment, a PNIPAM CCA is formed in an aqueous media and contained within cell means. In another embodiment, a CCA of charged particles is formed and polymerized in a PNIPAM hydrogel. Methods for making these devices are also disclosed. The devices of the present invention are useful in many applications including, for example, optical switches, optical limiters, optical filters, display devices and processing elements. The devices are further useful as membrane filters. All of these devices have the feature of being tunable in response to temperature. Devices that change diffracted wavelength in response to pressure are also disclosed.
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: December 26, 2000
    Assignee: University of Pittsburgh of the Commonwealth of Higher Education
    Inventors: Sanford A. Asher, Jesse M. Weissman, Hari B. Sunkara
  • Patent number: 6123845
    Abstract: A method of making a solid filter material which filters a predetermined wavelength band from a broader spectrum of radiation is provided. The method includes creating a colloidal structure composed of particles dispersed within a medium, and introducing a solvent thereto. Thereafter, the solvent is evaporated and the remaining structure solidifies into a solid crystalline array. The particles can also be fused together by polymerization using one of several methods which are provided. In another embodiment, methods of filtering submicron particles have been developed which consists of establishing a gel membrane from a crystalline colloidal array with an interstice size less than or equal to the particles to be filtered are disclosed. The gel membrane may employ anisotropic interstices of submicron size and is stretchable or compressible mechanically.
    Type: Grant
    Filed: September 15, 1998
    Date of Patent: September 26, 2000
    Assignee: University of Pittsburgh
    Inventors: Sanford A. Asher, Jay Henis
  • Patent number: 6097530
    Abstract: Devices that comprise novel, mesoscopically periodic materials that combine crystalline colloidal array (CCA) self-assembly with the temperature ined volume phase transitions of various materials, preferably poly(N-isopropylacrylamide) (PNIPAM) are disclosed. In one embodiment, a PNIPAM CCA is formed in an aqueous media and contained within cell means. In another embodiment, a CCA of charged particles is formed and polymerized in a PNIPAM hydrogel. Methods for making these devices are also disclosed. The devices of the present invention are useful in many applications including, for example, optical switches, optical limiters, optical filters, display devices and processing elements. The devices are further useful as membrane filters. All of these devices have the feature of being tunable in response to temperature. Devices that change diffracted wavelength in response to pressure are also disclosed.
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: August 1, 2000
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventors: Sanford A. Asher, Jesse M. Weissman, Hari B. Sunkara
  • Patent number: 6094273
    Abstract: Devices that comprise novel, mesoscopically periodic materials that combine crystalline colloidal array (CCA) self-assembly with the temperature ined volume phase transitions of various materials, preferably poly(N-isopropylacrylamide) (PNIPAM) are disclosed. In one embodiment, a PNIPAM CCA is formed in an aqueous media and contained within cell means. In another embodiment, a CCA of charged particles is formed and polymerized in a PNIPAM hydrogel. Methods for making these devices are also disclosed. The devices of the present invention are useful in many applications including, for example, optical switches, optical limiters, optical filters, display devices and processing elements. The devices are further useful as membrane filters. All of these devices have the feature of being tunable in response to temperature. Devices that change diffracted wavelength in response to pressure are also disclosed.
    Type: Grant
    Filed: September 15, 1998
    Date of Patent: July 25, 2000
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventors: Sanford A. Asher, Jesse M. Weissman, Hari B. Sunkara
  • Patent number: 6014246
    Abstract: Devices that comprise novel, mesoscopically periodic materials that combine crystalline colloidal array (CCA) self-assembly with the temperature ined volume phase transitions of various materials, preferably poly(N-isopropylacrylamide) (PNIPAM) are disclosed. In one embodiment, a PNIPAM CCA is formed in an aqueous media and contained within cell means. In another embodiment, a CCA of charged particles is formed and polymerized in a PNIPAM hydrogel. Methods for making these devices are also disclosed. The devices of the present invention are useful in many applications including, for example, optical switches, optical limiters, optical filters, display devices and processing elements. The devices are further useful as membrane filters. All of these devices have the feature of being tunable in response to temperature. Devices that change diffracted wavelength in response to pressure are also disclosed.
    Type: Grant
    Filed: November 6, 1996
    Date of Patent: January 11, 2000
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventors: Sanford A. Asher, Jesse M. Weissman, Hari B. Sunkara
  • Patent number: 6001251
    Abstract: A method of making a solid filter material which filters a predetermined wavelength band from a broader spectrum of radiation is provided. The method includes creating a colloidal structure composed of particles dispersed within a medium, and introducing a solvent thereto. Thereafter, the solvent is evaporated and the remaining structure solidifies into a solid crystalline array. The particles can also be fused together by polymerization using one of several methods which are provided. In another embodiment, methods of filtering submicron particles have been developed which consists of establishing a gel membrane from a crystalline colloidal array with an interstice size less than or equal to the particles to be filtered are disclosed. The gel membrane may employ anisotropic interstices of submicron size and is stretchable or compressible mechanically.
    Type: Grant
    Filed: October 26, 1998
    Date of Patent: December 14, 1999
    Assignee: University of Pittsburgh
    Inventors: Sanford A. Asher, Jay Henis
  • Patent number: 5944994
    Abstract: A coating material is provided which has fragments of a gel membrane filter in a liquid. The gel membrane filter has a plurality of electronegative particles provided in an ordered crystalline array. The gel membrane filter has been hardened with a polymer and is embodied in refractive fragments which alter the surface appearance of the resultant coating material. The coating material may be employed as a nail polish or as a paint.
    Type: Grant
    Filed: June 4, 1997
    Date of Patent: August 31, 1999
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventors: Sanford A. Asher, Jay Henis
  • Patent number: 5898004
    Abstract: Novel sensor devices composed of a crystalline colloidal array (CCA) polymerized in a hydrogel are disclosed. The hydrogels are characterized as being capable of shrinking and swelling in response to specific stimuli applied thereto. As the hydrogels shrink or swell, the lattice structure of the CCA embedded therein changes, thereby changing the wavelength of light diffracted by the CCA. Thus by monitoring the change in diffracted wavelength, the concentration of a stimulus is determined. The gels can be modified to sense numerous different stimuli. The sensor devices are specific in that they are modified to react with only one species or family of species. These sensors have various applications in areas including, for example, environmental and chemical systems, chemomechanical systems, sensor devices and medical diagnostic tools. Various methods for making and using these devices are also disclosed.
    Type: Grant
    Filed: November 6, 1996
    Date of Patent: April 27, 1999
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventors: Sanford A. Asher, John H. Holtz
  • Patent number: 5854078
    Abstract: Novel sensor devices composed of a crystalline colloidal array (CCA) polymerized in a hydrogel are disclosed. The hydrogels are characterized as being capable of shrinking and swelling in response to specific stimuli applied thereto. As the hydrogels shrink or swell, the lattice structure of the CCA embedded therein changes, thereby changing the wavelength of light diffracted by the CCA. Thus by monitoring the change in diffracted wavelength, the concentration of a stimulus is determined. The gels can be modified to sense numerous different stimuli. The sensor devices are specific in that they are modified to react with only one species or family of species. These sensors have various applications in areas including, for example, environmental and chemical systems, chemomechanical systems, sensor devices and medical diagnostic tools. Various methods for making and using these devices are also disclosed.
    Type: Grant
    Filed: March 17, 1997
    Date of Patent: December 29, 1998
    Assignee: University of Pittsburgh
    Inventors: Sanford A. Asher, John H. Holtz
  • Patent number: 5737102
    Abstract: Methods for making a nonlinear optical device and related devices are dissed. The method includes creating an ordered dispersion of charged particles in a surrounding medium. The charged particles and the surrounding medium are chosen such that they initially have identical refractive indices. In accordance with one aspect of the invention, cadmium sulfide inclusions are added to at least one of (a) the particles or (b) the medium. The cadmium sulfide inclusions have a highly nonlinear refractive index. The inclusions are optically nonlinear and upon high intensity radiation the refractive index of the particles change. This change in the refractive index occurs on the order of nanoseconds. In accordance with another aspect of the invention, a nonfluorescent dye is incorporated into at least one of (a) the particles or (b) the medium. The dye is photoabsorptive. Upon being impinged with high intensity radiation, the dye absorbs photons and heats the surrounding particles.
    Type: Grant
    Filed: September 18, 1995
    Date of Patent: April 7, 1998
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventor: Sanford A. Asher
  • Patent number: 5711884
    Abstract: A method of making a solid filter material which filters a predetermined wavelength band from a broader spectrum of radiation is provided. The method includes creating a colloidal structure composed of particles dispersed within a medium, and introducing a solvent thereto. Thereafter, the solvent is evaporated and the remaining structure solidifies into a solid crystalline array. The particles can also be fused together by polymerization using one of several methods which are provided. In another embodiment, methods of filtering submicron particles have been developed which consists of establishing a gel membrane from a crystalline colloidal array with an interstice size less than or equal to the particles to be filtered are disclosed. The gel membrane may employ anisotropic interstices of submicron size and is stretchable or compressible mechanically.
    Type: Grant
    Filed: November 21, 1995
    Date of Patent: January 27, 1998
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventors: Sanford A. Asher, Jay Henis
  • Patent number: 5452123
    Abstract: Methods for making a nonlinear optical device and related devices are dissed. The method includes creating an ordered dispersion of charged particles in a surrounding medium. The charged particles and the surrounding medium are chosen such that they initially have identical refractive indices. In accordance with one aspect of the invention, cadmium sulfide inclusions are added to at least one of (a) the particles or (b) the medium. The cadmium sulfide inclusions have a highly nonlinear refractive index. The inclusions are optically nonlinear and upon high intensity radiation the refractive index of the particles change. This change in the refractive index occurs on the order of nanoseconds. In accordance with another aspect of the invention, a nonfluorescent dye is incorporated into at least one of (a) the particles or (b) the medium. The dye is photoabsorptive. Upon being impinged with high intensity radiation, the dye absorbs photons and heats the surrounding particles.
    Type: Grant
    Filed: December 30, 1992
    Date of Patent: September 19, 1995
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventors: Sanford A. Asher, Song-Yuan Chang, Seshadri Jagannathan, Rasu Kesavamoorthy, Guisheng Pan
  • Patent number: 5368781
    Abstract: The present invention discloses a tunable, radiation filter comprising a highly ordered crystalline array of microparticles fixed in a polymerized hydrogel.
    Type: Grant
    Filed: November 10, 1993
    Date of Patent: November 29, 1994
    Assignee: Cytec Technology Corp.
    Inventors: Gottfried Haacke, Hans P. Panzer, Lino G. Magliocco, Sanford A. Asher
  • Patent number: 5281370
    Abstract: A method of making a solid filter material which filters a predetermined wavelength band from a broader spectrum of radiation includes creating a colloidal structure composed of particles dispersed within a medium, and introducing a solvent thereto. Thereafter, the solvent is evaporated and the remaining structure solidifies into a solid crystalline array. Another embodiment of the method includes electrophoretically attracting the particles in a medium to form an ordered array. The particles can also be fused together by polymerization using one of several methods which are provided. Additionally, one aspect of the invention involves coating the particles with an electrostatically-charged material to facilitate inter-particle interactions.
    Type: Grant
    Filed: August 22, 1990
    Date of Patent: January 25, 1994
    Assignee: University of Pittsburgh of the Commonwealth System of Higher Education
    Inventors: Sanford A. Asher, Sesh Jagannathan
  • Patent number: 5266238
    Abstract: The present invention discloses a tunable, radiation filter comprising a highly ordered crystalline array of microparticles fixed in a polymerized hydrogel.
    Type: Grant
    Filed: December 24, 1990
    Date of Patent: November 30, 1993
    Assignee: American Cyanamid Company
    Inventors: Gottfried Haacke, Hans P. Panzer, Lino G. Magliocco, Sanford A. Asher