Shan Living Wang

US Patent:

7238486, Jul 3, 2007

Filed:

Sep 20, 2005

Appl. No.:

11/231657

Inventors:

Nader Pourmand - Mountain View CA, US
Ronald W. Davis - Palo Alto CA, US
Shan X. Wang - Portola Valley CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

C12Q 1/68
C07H 21/02
C07H 21/04

US Classification:

435 6, 536 231, 536 243

Abstract:

A method of determining the length of a polynucleotide target is provided. With this method, a target is first hybridized to an array of first probes having different, determined lengths, resulting in the formation of duplexes between the polynucleotide target and the first probes. These duplexes have a single stranded section of target if the target is longer than the first probe it is in a duplex with. Next, a second probe having a determined length is hybridized to these duplexes. If the length of the target is greater than the length of the first probe it is displaced during this hybridization step by the process of branch migration. In contrast, if the length of the target is less than or equal to the length of the first probe, it is not displaced. Thus, the length of the polynucleotide target can be determined.

US Patent:

7419639, Sep 2, 2008

Filed:

Mar 22, 2006

Appl. No.:

11/388223

Inventors:

Sebastian J Osterfeld - Stanford CA, US
Shan X. Wang - Portola Valley CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

B01L 3/02
G01N 15/06
G01N 33/00
G01N 33/48

US Classification:

422100, 422 50, 422 681, 436 43, 436 63, 436174, 436180

Abstract:

The present invention provides microfluidic devices constructed from four layers. The layers include a rigid substrate layer, a patterned rigid layer having thickness t, a patterned elastomeric layer having thickness greater than t, and a rigid support layer. Microfluidic structures in the devices are defined by the alignment of openings in the patterned rigid layer and the patterned elastomeric layer. The rigid support layer, rigid substrate layer, and patterned rigid layer may be made of any rigid material, including but not limited to plastic or silicon-containing materials, such as glass, quartz, or SiO-coated materials. Similarly, the patterned elastomeric layer may be made of any elastomeric material, including but not limited to polydimethylsiloxanes, polymethylmethacrylates, perfluoropolyethers, or combinations thereof. Microfluidic devices according to the present invention may include sensors or sensor arrays. The microfluidic devices are fabricated using the provided error-tolerant alignment, biocompatible process.

US Patent:

7501253, Mar 10, 2009

Filed:

Apr 24, 2007

Appl. No.:

11/789559

Inventors:

Nader Pourmand - San Mateo CA, US
Ronald W. Davis - Palo Alto CA, US
Shan X. Wang - Portola Valley CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

C12Q 1/68
C07H 21/02
C07H 21/04

US Classification:

435 6, 536 231, 536 243

Abstract:

A method of determining the length of a polynucleotide target is provided. With this method, a target is first hybridized to an array of first probes having different, determined lengths, resulting in the formation of duplexes between the polynucleotide target and the first probes. These duplexes have a single stranded section of target if the target is longer than the first probe it is in a duplex with, and a single stranded section of probe if the target is shorter than the first probe it is in a duplex with. Next, a series of probes is hybridized to the duplexes, breaking apart duplexes in which the target and probe have unequal lengths through the process of branch migration. Thus, the target only remains bound in the duplex if the target and probe are of equal lengths. The length of the polynucleotide target can thereby be determined.

US Patent:

7615382, Nov 10, 2009

Filed:

Nov 9, 2006

Appl. No.:

11/595818

Inventors:

Shan X. Wang - Portola Valley CA, US
Nader Pourmand - San Mateo CA, US
Robert L. White - Stanford CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

G01N 33/553
B03C 1/30

US Classification:

436526, 436518, 436538, 209 38, 209214, 209215

Abstract:

The present invention provides a magnetic sifter that is small in scale, enables three-dimensional flow in a direction normal to the substrate, allows relatively higher capture rates and higher flow rates, and provides a relatively easy method of releasing captured biomolecules. The magnetic sifter includes at least one substrate. Each substrate contains a plurality of slits, each of which extends through the substrate. The sifter also includes a plurality of magnets attached to the bottom surface of the substrate. These magnets are located proximal to the openings of the slits. An electromagnetic source controls the magnitude and direction of magnetic field gradient generated by the magnets. Either one device may be used, or multiple devices may be used in series. In addition, the magnetic sifter may be used in connection with a detection chamber.

US Patent:

7682838, Mar 23, 2010

Filed:

Nov 9, 2007

Appl. No.:

11/938187

Inventors:

Shan X. Wang - Portola Valley CA, US
Robert L. White - Stanford CA, US
Chris D. Webb - Scotts Valley CA, US
Guanxiong Li - Stanford CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

G01N 33/543
G01N 1/36

US Classification:

436526, 436518, 422 50, 422 98, 422276, 365173, 209214, 210222, 210223

Abstract:

Magnetic nanoparticles and methods for their use in detecting biological molecules are disclosed. The magnetic nanoparticles can be attached to nucleic acid molecules, which are then captured by a complementary sequence attached to a detector, such as a spin valve detector or a magnetic tunnel junction detector. The detection of the bound magnetic nanoparticle can be achieved with high specificity and sensitivity.

US Patent:

7906345, Mar 15, 2011

Filed:

Apr 22, 2004

Appl. No.:

10/829505

Inventors:

Shan X Wang - Portola Valley CA, US
Robert L White - Stanford CA, US
Chris D Webb - Scotts Valley CA, US
Guanxiong Li - Stanford CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

G01N 33/553
G01N 33/53

US Classification:

436526, 436518, 436501, 428403

Abstract:

Magnetic nanoparticles and methods for their use in detecting biological molecules are disclosed. The magnetic nanoparticles can be attached to nucleic acid molecules, which are then captured by a complementary sequence attached to a detector, such as a spin valve detector or a magnetic tunnel junction detector. The detection of the bound magnetic nanoparticle can be achieved with high specificity and sensitivity.

US Patent:

7939338, May 10, 2011

Filed:

May 11, 2005

Appl. No.:

11/128105

Inventors:

Shan X. Wang - Portola Valley CA, US
Shu-Jen Han - Stanford CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

G01R 33/00

US Classification:

436149, 436 56, 422 681, 422 8201, 210222

Abstract:

A magnetic sensor array including magnetoresistive sensor elements having outputs combined by frequency division multiplexing (FDM) is provided. Each sensor element provides an input to a mixer which provides a distinct frequency shift. Preferably, time division multiplexing is also used to combine sensor element outputs. Each sensor element is typically in proximity to a corresponding sample. The sensor elements are preferably subarrays having row and column addressable sensor element pixels. This arrangement provides multiple sensor pixels for each sample under test. Multiplexing of sensor element outputs advantageously reduces readout time. A modulated external magnetic field is preferably applied during operation, to reduce the effect of 1/f noise on the sensor element signals. The effect of electromagnetic interference (EMI) induced by the magnetic field on sensor element signals is advantageously reduced by the mixing required for FDM.

US Patent:

7989396, Aug 2, 2011

Filed:

Dec 3, 2007

Appl. No.:

11/949442

Inventors:

Heng Yu - Mountain View CA, US
Nader Pourmand - San Mateo CA, US
Shan X. Wang - Portola Valley CA, US

Assignee:

The Board of Trustees of the Leland Stanford Junior University - Palo Alto CA

International Classification:

C40B 50/18
C40B 60/02

US Classification:

506 32, 506 34

Abstract:

A highly specific and versatile surface chemistry for immobilization of amine-terminated probes is disclosed. A bi-layered polymer thin film serves as the platform for coupling the probes, which are preferably oligonucleotides. The process involves sequentially coating a substrate with polyamine and polyacid anhydride. Hydrolyzed polyacid anhydride groups may be converted to non-hydrolyzed groups at about 100 C. prior to probe attachment. The process of coating the substrate requires no harsh chemical pretreatment of substrates such as RCA or Piranha cleaning. In addition, simple thermal activation of the anhydride groups has a low requirement for storage, leading to a long shelf life of modified surfaces. The disclosed surface chemistry is especially compatible with microfabrication processes, and its effective application to magnetic biosensors is demonstrated.