Paul W Shieh, 685306 Judsonville Dr, Antioch, CA 94531

2005008, Apr 28, 2005

Oct 27, 2003

10/695273

Paul Shieh - Fremont CA, US
Ching-Hsin Cho - San Chung, TW

BioMedix, Inc. - Fremont CA

C12Q001/54

435014000

An amperometric glucose biosensor comprises a sensing electrode and a reference electrode arranged in a side-by-side parallel configuration on an electrically insulating sheet. A passive cover electrode is placed over the side-by-side sensing electrode and reference electrode so that the active surface of the passive cover electrode opposes the active surfaces of the side-by-side electrodes. Physical contact between the passive covering electrode and the side-by-side electrodes is prevented by insulating spacers. The sensing electrode comprises a conductive graphite track coated with a formulation comprising a redox mediator and enzyme and the reference electrode is a parallel track comprising an Ag/AgCl formulation while the passive cover electrode comprising a conductive graphite track coated with a formulation comprising the same redox mediator as used in the sensing electrode but not including an enzyme. An opening either located in the middle or at one side of the passive cover electrode allows a liquid test sample to be introduced into the sensor. The biosensor of the present invention exhibits a sensitivity and response time equal to or surpassing that of the simple face-to-face configuration while can be efficiently manufactured and permit use with conventional electrical connectors.

6033866, Mar 7, 2000

Dec 8, 1997

8/986974

Dingli Guo - Union City CA
Paul Shieh - Fremont CA
Esfir Goldberg - San Francisco CA

Biomedix, Inc. - Fremont CA

C12Q 154
C12Q 100
C12Q 126
C12Q 128

435 14

A highly sensitive sensor for the amperometric assay of glucose in aqueous media having a face-to-face sandwich configuration is provided which comprises a sensing electrode strip containing a first redox mediator in an electrically conductive coating and a reference electrode strip in simultaneous contact with a reagent strip containing a second redox mediator which is sandwiched between the active electrode surfaces. An opening is provided in the reference electrode for the introduction of samples. In one embodiment, a whole blood separation membrane is interposed between the reference electrode and the reagent strip to filter red blood cells and other particles from whole blood to enable direct assay of glucose without sample preparation. The sensing electrode comprises a non-conductive support member having an electrically conductive layer containing the first redox mediator. The reference electrode is typically a Ag/AgCl electrode formed by coating an ink containing Ag/AgCl dispersed in a resin on a non-conductive base.

5876952, Mar 2, 1999

Dec 8, 1997

8/986432

Paul Shieh - Fremont CA

C12Q 154
C12Q 100
C12Q 126
C12Q 128

435 14

An amperometric glucose biosensor having high sensitivity and accuracy over a wide range of glucose concentrations and a method for the rapid detection of glucose in urine are provided. The biosensor strip comprises an electrically conductive carbon layer, having a first redox mediator, a reagent strip containing an enzyme system for the oxidation of glucose and a second redox mediator, and a silver/silver chloride reference electrode. In a preferred form of the sensor that has high sensitivity, a sensing electrode and a reference electrode are arranged so that the electrically conductive layers of the electrodes are face-to-face and sandwich the reagent strip between them. Screening for glucose is achieved by contacting the sensor with a drop of the patient's urine and comparing the current read-out with a standard calibration curve or by automatically converting the current flow generated by the test sample to units of glucose concentration. The sensor can measure urine glucose concentrations below 3 mg/dl. Measurement of urine glucose concentration with the sensor provides a non-invasive probe of a patient's blood glucose level since a linear relationship exists between blood glucose concentration and urine glucose concentration, approximately in the range between 0 to 400 mg/dl.

5401377, Mar 28, 1995

Aug 6, 1993

8/103193

Paul Shieh - Fremont CA
Dingli Guo - Newark CA

Biomedix, Inc. - Fremont CA

G01N 2726

204418

An ion-selective electrode having an ion-selective membrane in direct contact with an electrical conductor is provided in which the membrane coats an uninsulated zone surrounded by insulation on the surface of a conductor which is coated with a layer of electrical insulation. The membrane overlays the insulation surrounding the insulation free zone and comprises a polymer which is generally of sufficiently similar composition to that comprising the electrical insulation layer so that it adheres to the insulation forming a membrane with increased structural strength. Embodiments of the electrode containing phosphatidylcholine in the ion-selective membrane have increased sensitivity.

5522977, Jun 4, 1996

Oct 7, 1994

8/319618

Paul Shieh - Fremont CA

Biomedix, Inc. - Fremont CA

G01N 27327
G01N 27333

204403

A redox electrode for the rapid detection of glucose in aqueous media and a method for its use are provided. The redox electrode comprises an electrically conductive member such as copper, and a redox membrane in direct contact with said electrically conductive member. The redox membrane comprises a polymer matrix such as PVC containing a plasticizer, and a complex of 7,7,8,8 -tetracyanoquinodimethane and tetrathiafulvalene with the complex having a burgundy-red coloration and characterized by a broad absorption from about 340 nm to about 550 nm and weaker absorption between about 650 nm to about 800 nm having about six small peaks with an absorption maximum at about 750nm. Glucose is rapidly assayed by bringing the redox electrode and a reference electrode into simultaneous contact with an aqueous medium containing KCl, phosphate buffer, glucose oxidase, peroxidase, and 3,3',5,5'-tetramethylbenzidine dihydrochloride. The potential of the redox membrane is then monitored until it is stable. A sample containing glucose is added to the aqueous medium, and the change of potential of the redox electrode, which is related to glucose concentration, is then observed.

4489150, Dec 18, 1984

Jun 8, 1983

6/502256

Paul Shieh - Fremont CA

Ricoh Company, Ltd. - Tokyo

G03G 908

430106

A novel toner composition with improved thermal and rheological properties, improved surface energy, and better frangibility is provided. The toner comprises a thermoplastic polymeric blend and a coloring agent. The polymeric blend is comprised of propoxylated bisphenol-A fumarate and a polyester resin with a chemically bound halogen. A preferred polyester resin with a chemically bound halogen is tetrabromo-bisphenol fumarate polyester. An improved electrophotographic imaging process using the toner particles of the present invention is also provided.

6054039, Apr 25, 2000

Aug 18, 1997

8/914283

Paul Shieh - Fremont CA

G01N 2726

205792

A method of determining the concentration of glycoproteins and glycosylated hemoglobin in whole blood and whole blood components by means of an amperometric biosensor and an amperometric biosensor for this determination are provided. In one embodiment, whole blood is introduced into a version of an amperometric sensor having a component that removes erythrocytes. Redox mediators are used to obtain a current flow based on the oxidation of fructosamine derivatives that can be correlated with the concentration of glycosylated proteins in the fraction of the blood from which erythrocytes have been excluded. To obtain the concentration of glycosylated hemoglobin, whole blood is introduced into a version of the sensor which includes a component that produces lysis of the erythrocytes yielding a current flow proportional to the total quality of glycosylated proteins including glycosylated hemoglobin. The glycosyltaed hemoglobin concentration is obtained by subtracting the glycoprotein concentration in the absence of erythrocytes from the glycoprotein concentration of the lysed whole blood. The sensor generally comprises a sensing electrode having a first redox mediator dispersed in an electrically conductive medium such as an electrically conductive graphite formulation; a reference electrode such as a standard silver-silver chloride electrode; a reagent strip containing a pH buffer and a second redox mediator system in a gel medium; and a whole blood treatment component consisting of either a membrane or other means to filter erythrocytes from whole blood or a means to lyse erythrocytes.

5645710, Jul 8, 1997

Mar 18, 1996

8/617278

Paul Shieh - Fremont CA

Biomedix, Inc. - Fremont CA

G02N 2726
C12Q 154
C12Q 128

205778

A redox electrode for the rapid detection of glucose in aqueous media and a method for its use are provided. The redox electrode comprises an electrically conductive member such as copper, and a redox membrane in direct contact with said electrically conductive member. The redox membrane comprises a polymer matrix such as PVC containing a plasticizer, and a complex of 7,7,8,8-tetracyanoquinodimethane and tetrathiafulvalene with the complex having a burgundy-red coloration and characterized by a broad absorption from about 340 nm to about 550 nm and weaker absorption between about 650 nm to about 800 nm having about six small peaks with an absorption maximum at about 750 nm. Glucose is rapidly assayed by bringing the redox electrode and a reference electrode into simultaneous contact with an aqueous medium containing KCl, phosphate buffer, glucose oxidase, peroxidase, and 3,3',5,5'-tetramethylbenzidine dihydrochloride. The potential of the redox membrane is then monitored until it is stable. A sample containing glucose is added to the aqueous medium, and the change of potential of the redox electrode, which is related to glucose concentration, is then observed.