Vinayak P Dravid

US Patent:

7155959, Jan 2, 2007

Filed:

Feb 18, 2004

Appl. No.:

10/782720

Inventors:

Ming Su - Evanston IL, US
Vinayak P. Dravid - Glenview IL, US

Assignee:

Northwestern University - Evanston IL

International Classification:

G01N 7/00

US Classification:

73 3105

Abstract:

The invention provides a sensor array with different nanodisk sensors that may be fabricated by direct site-specific dip-pen nanopatterning (DPN) using precursor inks. The good flow characteristics and strong affinity of the sols to measurement electrodes enable intimate ohmic contact. The measurable, reproducible and proportionate changes in the resistance of the sensors when exposed to trace quantities of oxidative and reducing gases constitute the basis for nanodisk gas sensors. The nanodisk sensors show rapid response and ultra-fast recovery for the detection of nitrogen dioxide and acetic acid vapor. Based on the principles of pattern recognition of the olfactory system, an electronic nose that can “smell” different gaseous species is provided with the multiple nanodisk sensor array. These nanodisk sensors have gas recognition ability, instant response and rapid recovery, compact size and integration with the established microelectronics platform and are well-suited for the on-site and real-time detection of gases.

US Patent:

7157897, Jan 2, 2007

Filed:

Nov 23, 2004

Appl. No.:

10/996274

Inventors:

Gajendra Shekhawat - Arlington Heights IL, US
Vinayak P. Dravid - Glenview IL, US

Assignee:

Northwestern University - Evanston IL

International Classification:

G01N 27/00
G01B 5/28

US Classification:

324 711, 324 714, 73105, 73580

Abstract:

A sensor for detecting mechanical perturbations represented by a change in an electrical signal includes a structure such as a cantilever, membrane, etc. and a field effect transistor such as a MOSFET embedded in the structure. The drain current of the embedded transistor changes with mechanical perturbations in the structure caused, for example, by a bio-chemical interaction being sensed. A scanning probe microscope utilizes the embedded MOSFET with a BiMOS actuator.

US Patent:

7223438, May 29, 2007

Filed:

Sep 17, 2003

Appl. No.:

10/663976

Inventors:

Chad A. Mirkin - Wilmette IL, US
Lei Fu - Evanston IL, US
Xiaogang Liu - Evanston IL, US
Vinayak P. Dravid - Glenview IL, US

Assignee:

Northwestern University - Evanston IL

International Classification:

B05D 5/12

US Classification:

427127, 427 11, 427256, 427258, 427261, 427265, 427269, 427287, 1014501, 101483, 101491, 250306, 250310, 250311

Abstract:

A direct-write method for fabricating magnetic nanostructures, including hard magnetic nanostructures of barium hexaferrite, BaFe, based on nanolithographic printing and a sol-gel process. This method utilizes a conventional atomic force microscope tip, coated with a magnetic material precursor solution, to generate patterns that can be post-treated at elevated temperature to generate magnetic features consisting of barium ferrite in its hexagonal magnetoplumbite (M-type) structure. Features ranging from several hundred nm down to below 100 nm were generated and studied using AFM, magnetic force microscopy, and X-ray photoelectron spectroscopy. The approach offers a new way for patterning functional inorganic magnetic nanostructures with deliberate control over feature size and shape, as well as interfeature distance and location.

US Patent:

7273636, Sep 25, 2007

Filed:

Dec 17, 2002

Appl. No.:

10/320721

Inventors:

Chad A. Mirkin - Wilmette IL, US
Vinayak P. Dravid - Glenview IL, US
Ming Su - Evanston IL, US
Xiaogang Liu - Evanston IL, US

Assignee:

Northwestern University - Evanston IL

International Classification:

B05D 5/00
B05D 3/02

US Classification:

427256, 427226, 427229, 977855, 977857

Abstract:

The present invention includes a method of fabricating organic/inorganic composite nanostructures on a substrate comprising depositing a solution having a block copolymer and an inorganic precursor on the substrate using dip pen nanolithography. The process can comprise providing a substrate, providing a nanoscopic tip having an inking composition thereon, wherein the inking composition comprises at least one metal oxide precursor; and transferring the inking composition from the nanoscopic tip to the substrate to form a deposit on the substrate comprising at least one metal oxide precursor, and optionally further comprising the step of converting the metal oxide precursor on the substrate to form the metal oxide. The nanostructures comprises arrays of lines and/or dots having widths/diameters less than 1 micron. The present invention also includes a device comprising an organic/inorganic composite nanoscale region chemically bonded to a substrate, wherein the nanoscale region, wherein the nanoscale region has a nanometer scale dimension other than height.

US Patent:

7448269, Nov 11, 2008

Filed:

Oct 6, 2005

Appl. No.:

11/244747

Inventors:

Gajendra Shekhawat - Arlington Heights IL, US
Vinayak P. Dravid - Glenview IL, US

Assignee:

Northwestern University - Evanston IL

International Classification:

G01N 29/04
G01V 1/00

US Classification:

73603, 73596, 181101

Abstract:

A high spatial resolution phase-sensitive technique employs a scanning near field ultrasound holography (SNFUH) methodology for imaging elastic as well as viscoelastic variations across a sample surface. SNFUH uses a near-field approach to measure time-resolved variations in ultrasonic oscillations at a sample surface. As such, it overcomes the spatial resolution limitations of conventional phase-resolved acoustic microscopy (i. e. holography) by eliminating the need for far-field acoustic lenses.

US Patent:

7722928, May 25, 2010

Filed:

Apr 7, 2005

Appl. No.:

11/100483

Inventors:

Chad A. Mirkin - Wilmette IL, US
Seunghun Hong - Chicago IL, US
Vinayak P. Dravid - Glenview IL, US

Assignee:

Northwestern University - Evanston IL

International Classification:

B05D 5/00
B05D 1/36
B05D 7/24
B01J 19/08
C12Q 1/68
C12P 19/34

US Classification:

427256, 118664, 427287, 427457, 427595, 427598

Abstract:

In one aspect, a method of nanolithography is provided using a driving force to control the movement of a deposition compound from a scanning probe microscope tip to a substrate. Another aspect of the invention provides a tip for use in nanolithography having an internal cavity and an aperture restricting movement of a deposition compound from the tip to the substrate. The rate and extent of movement of the deposition compound through the aperture is controlled by a driving force.

US Patent:

7744963, Jun 29, 2010

Filed:

Oct 31, 2007

Appl. No.:

11/933181

Inventors:

Chad A. Mirkin - Wilmette IL, US
Seunghun Hong - Chicago IL, US
Vinayak P. Dravid - Glenview IL, US

Assignee:

Northwestern University - Evanson IL

International Classification:

B05D 1/28
B05D 3/14

US Classification:

427457, 427458, 427598, 427256, 427128, 977850, 977857, 977860, 977862, 977863, 977878, 977882, 977884, 977885, 977886

Abstract:

In one aspect, a method of nanolithography is provided, the method comprising providing a substrate; providing a scanning probe microscope tip; coating the tip with a deposition compound; and subjecting said coated tip to a driving force to deliver said deposition compound to said substrate so as to produce a desired pattern. Another aspect of the invention provides a tip for use in nanolithography having an internal cavity and an aperture restricting movement of a deposition compound from the tip to the substrate. The rate and extent of movement of the deposition compound through the aperture is controlled by a driving force.

US Patent:

7759924, Jul 20, 2010

Filed:

Dec 4, 2006

Appl. No.:

11/566557

Inventors:

Gajendra Shekhawat - Arlington Heights IL, US
Vinayak P Dravid - Glenview IL, US
Soo-Hyun Tark - Evanston IL, US
Arvind K Srivastava - Des Plaines IL, US

Assignee:

Northwestern University - Evanston IL

International Classification:

G01N 27/00
G01B 5/28

US Classification:

324 711, 73105, 73580

Abstract:

A sensor for detecting mechanical perturbations represented by a change in an electrical signal includes a structure such as a cantilever, membrane, etc. and a field effect transistor such as a MOSFET embedded in the structure. The drain current of the embedded transistor changes with mechanical perturbations in the structure caused, for example, by a biochemical interaction being sensed. A scanning probe microscope utilizes the embedded MOSFET with a BiMOS actuator.