Govind D Rao

6426505, Jul 30, 2002

Jan 19, 2000

09/487275

Govind Rao - Columbia MD
Peter Harms - Baltimore MD

University of Maryland Biotechnology Institute - College Park MD
University of Maryland Baltimore County - Baltimore MD

G01N 2164

2504581, 2504591, 356318

A low cost apparatus and method for measuring nanosecond luminescence lifetimes with a modulated LED light source that is driven by a lock-in amplifier. The lock-in amplifier provides both a DC bias and an AC signal used to modulate the intensity of an LED source light at a wavelength capable of exciting a photoluminescent species. Excitation of the photoluminescent species produces a corresponding emission. The emission, which can be detected in a variety of ways, was measured by a photomultiplier tube with the resulting signal being sent through a DC block back to the lock-in amplifier with no external signal processing or heterodyning required. The measuring process can be controlled by a computer through a GPIB, USB, serial or similar connection. The computer can also be used to correct for the most common sources of error, namely coherent pickup and stray ambient light. The apparatus without the computer has a component cost of less than US $10,000.

6563585, May 13, 2003

Nov 30, 1999

09/449671

Govind Rao - Columbia MD
Yordan Kostov - Baltimore MD

University of Maryland Biotechnology Institute - Baltimore MD
University of Maryland, Baltimore County - Baltimore MD

G01N 2100

356436, 356432, 356 39

A method and apparatus for measuring the concentration of various analytes in a sample using native fluorescence is described. A first light source for producing a first light having a first wavelength is directed at the sample to produce a first emission from the sample, a second light source for producing a second light having a second wavelength is directed at the sample to produce a second emission from the sample. A detecting device for detecting the first and second emissions emitted from the sample, and a controlling device responsive to the detecting device for alternately switching between the first and second light source so that only one light source is directing light at the sample at any one time are employed to excite emissions from the sample to be analyzed. An analyzing device that is responsive to the controlling device for producing a duty ratio is used to determine the analytic concentration of the specific analyte present in the sample.

6673532, Jan 6, 2004

Aug 14, 2001

09/928662

Govind Rao - Columbia MD

University of Maryland, Baltimore County - Baltimore MD

C12Q 100

435 4, 435 6, 4352871, 4352883, 4352887

The inventive bioprocessing system (and technique) relies on non-invasive optical chemical sensing technology wherein an optical excitation source excites an optical chemical sensor. The optical chemical sensor then emits luminescence or absorbs light which is measured by a detector. The luminescence emitted from the chemical sensor or the amount of light absorbed by the chemical sensor is related to the concentration of an analyte, such as oxygen. If the luminescence emitted changes, or if the amount of light absorbed changes, then the concentration of the analyte has changed. Using such a system to measure and adjust multiple parameters at one time allows one to efficiently and cost-effectively determine optimal conditions for a given cell type and/or cell environment, for example. By combining cell cultivation with optical chemical sensing technology, cultivation can be successfully and rapidly performed, controlled and monitored in small volumes in an automated, parallel fashion at less expense than current bioprocess techniques.

6699717, Mar 2, 2004

Feb 12, 1997

08/799410

Govind Rao - Columbia MD
Qing Chang - Carmel IN
Joseph R. Lakowicz - Ellicott City MD
Zakir Murtaza - Vernon Hills IL

The University of Maryland Baltimore County - Baltimore MD
The University of Maryland Biotechnology Institute - Baltimore MD

G01N 2164

436 39, 436132, 436172

The present invention relates to a transition metal-ligand complex that shows changes in its luminescence lifetime characteristic and/or luminescence intensity as a function of the polarity and/or hydrogen bonding properties of its environment, and a sensor, probe, system and method based on the complex for detecting the presence, amount or concentration of a polar solvent in a medium.

7041493, May 9, 2006

Dec 12, 2003

10/733412

Govind Rao - Columbia MD, US

University of Maryland, Baltimore County - Baltimore MD

C12M 1/34

4352881, 4352884, 422 8205, 356319, 356320, 356326, 356246

The inventive bioprocessing system (and technique) relies on non-invasive optical chemical sensing technology wherein an optical excitation source excites an optical chemical sensor. The optical chemical sensor then emits luminescence or absorbs light which is measured by a detector. The luminescence emitted from the chemical sensor or the amount of light absorbed by the chemical sensor is related to the concentration of an analyte, such as oxygen. If the luminescence emitted changes, or if the amount of light absorbed changes, then the concentration of the analyte has changed. Using such a system to measure and adjust multiple parameters at one time allows one to efficiently and cost-effectively determine optimal conditions for a given cell type and/or cell environment, for example. By combining cell cultivation with optical chemical sensing technology, cultivation can be successfully and rapidly performed, controlled and monitored in small volumes in an automated, parallel fashion at less expense than current bioprocess techniques.

7041986, May 9, 2006

Mar 14, 2003

10/389110

Govind Rao - Columbia MD, US
Peter Harms - Ellicott City MD, US
Iordan V. Kostov - Baltimore MD, US

University of Maryland Baltimore County - Baltimore MD

G01N 21/64

2504581, 2504591

The present invention provides methods for determining fluorescence lifetime of a fluorophor or an optical sensor using frequency domain gated detection. The method comprises the steps of exciting the fluorophor with frequency modulated light from a pulsed light source, gating a photodetector during excitation of the fluorophore, detecting light emitted from the fluorophor with the photodetector, where the emission light exhibits a phase shift in frequency from that of the excitation light, converting the detected excitation light to an amplified electric signal, and evaluating the amplified electric signal as a measure of fluorescence lifetime of the fluorophor. Also provided is a device with which to use the methods disclosed herein.

7390462, Jun 24, 2008

Jun 30, 2003

10/609720

Govind Rao - Columbia MD, US
Iordan V. Kostov - Baltimore MD, US
Haley R. Kermis - Baltimore MD, US
Peter Harms - Ellicott City MD, US

The University of Maryland Baltimore County - Baltimore MD

G01N 21/00
G01N 21/64
G01N 21/66
G01N 21/76
G01N 33/50
G01N 31/16
G01N 31/22
G01J 1/48

422 8208, 422 8205, 422 55, 422 86, 436 68, 436163, 436172

The present invention provides ratiometric fluorescent pH sensors for non-invasive, continuous monitoring of pH in such applications as fermentation processes. The ratiometric fluorescent pH sensors comprise a fluorescent dye that exhibits a shift in excitation wavelength with a corresponding shift in pH in the local environment of said fluorescent dye. Ratiometric measurements of the emission intensities at dual excitation maxima correlate to pH. Also provided is a fluorescent dye 6-methacryloyl-8-hydroxy-1,3-pyrene disulfonic acid (MA-HPDS). Further provided are systems and methods to non-invasively and continuously monitor pH.

7718353, May 18, 2010

Mar 1, 2004

10/552164

Leah Tolosa - Columbia MD, US
Govind Rao - Columbia MD, US
Xudong Ge - Ellicott City MD, US

University of Maryland Baltimore County - Baltimore MD

C12Q 1/00

435 4

A protein sensing molecule is capable of binding an analyte in a sample. The protein sensing molecule includes a first detectable quality that changes in a concentration dependent manner when the protein sensing molecule is bound to the analyte. The protein sensing molecule also includes a second detectable quality that does not undergo substantial change when the protein sensing molecule is bound to the analyte. The protein sensing molecule may be used in methods for characterizing samples and may also be used in sensors.