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).
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Publication number: 20020031841Abstract: 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: ApplicationFiled: May 25, 2001Publication date: March 14, 2002Inventors: Sanford A. Asher, Chad E. Reese
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Publication number: 20020032246Abstract: 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: ApplicationFiled: June 25, 1999Publication date: March 14, 2002Inventors: SANFORD A. ASHER, LEI LIU
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Publication number: 20020008229Abstract: 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: ApplicationFiled: February 23, 2001Publication date: January 24, 2002Inventors: Sanford A. Asher, Marta Kamenjicki, Igor K. Lednev, Viktor Meier
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Publication number: 20010026946Abstract: 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: ApplicationFiled: January 3, 2001Publication date: October 4, 2001Inventor: Sanford A. Asher
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Patent number: 6187599Abstract: 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: GrantFiled: July 7, 1998Date of Patent: February 13, 2001Assignee: University of PittsburghInventors: Sanford A. Asher, John H. Holtz
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Patent number: 6165389Abstract: 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: GrantFiled: March 10, 1999Date of Patent: December 26, 2000Assignee: University of Pittsburgh of the Commonwealth of Higher EducationInventors: Sanford A. Asher, Jesse M. Weissman, Hari B. Sunkara
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Patent number: 6123845Abstract: 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: GrantFiled: September 15, 1998Date of Patent: September 26, 2000Assignee: University of PittsburghInventors: Sanford A. Asher, Jay Henis
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Patent number: 6097530Abstract: 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: GrantFiled: March 10, 1999Date of Patent: August 1, 2000Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventors: Sanford A. Asher, Jesse M. Weissman, Hari B. Sunkara
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Patent number: 6094273Abstract: 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: GrantFiled: September 15, 1998Date of Patent: July 25, 2000Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventors: Sanford A. Asher, Jesse M. Weissman, Hari B. Sunkara
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Patent number: 6014246Abstract: 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: GrantFiled: November 6, 1996Date of Patent: January 11, 2000Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventors: Sanford A. Asher, Jesse M. Weissman, Hari B. Sunkara
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Patent number: 6001251Abstract: 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: GrantFiled: October 26, 1998Date of Patent: December 14, 1999Assignee: University of PittsburghInventors: Sanford A. Asher, Jay Henis
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Patent number: 5944994Abstract: 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: GrantFiled: June 4, 1997Date of Patent: August 31, 1999Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventors: Sanford A. Asher, Jay Henis
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Patent number: 5898004Abstract: 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: GrantFiled: November 6, 1996Date of Patent: April 27, 1999Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventors: Sanford A. Asher, John H. Holtz
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Patent number: 5854078Abstract: 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: GrantFiled: March 17, 1997Date of Patent: December 29, 1998Assignee: University of PittsburghInventors: Sanford A. Asher, John H. Holtz
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Patent number: 5737102Abstract: 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: GrantFiled: September 18, 1995Date of Patent: April 7, 1998Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventor: Sanford A. Asher
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Patent number: 5711884Abstract: 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: GrantFiled: November 21, 1995Date of Patent: January 27, 1998Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventors: Sanford A. Asher, Jay Henis
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Patent number: 5452123Abstract: 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: GrantFiled: December 30, 1992Date of Patent: September 19, 1995Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventors: Sanford A. Asher, Song-Yuan Chang, Seshadri Jagannathan, Rasu Kesavamoorthy, Guisheng Pan
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Patent number: 5368781Abstract: The present invention discloses a tunable, radiation filter comprising a highly ordered crystalline array of microparticles fixed in a polymerized hydrogel.Type: GrantFiled: November 10, 1993Date of Patent: November 29, 1994Assignee: Cytec Technology Corp.Inventors: Gottfried Haacke, Hans P. Panzer, Lino G. Magliocco, Sanford A. Asher
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Patent number: 5281370Abstract: 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: GrantFiled: August 22, 1990Date of Patent: January 25, 1994Assignee: University of Pittsburgh of the Commonwealth System of Higher EducationInventors: Sanford A. Asher, Sesh Jagannathan
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Patent number: 5266238Abstract: The present invention discloses a tunable, radiation filter comprising a highly ordered crystalline array of microparticles fixed in a polymerized hydrogel.Type: GrantFiled: December 24, 1990Date of Patent: November 30, 1993Assignee: American Cyanamid CompanyInventors: Gottfried Haacke, Hans P. Panzer, Lino G. Magliocco, Sanford A. Asher