US4735906A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sensor having piezoelectric crystal for microgravimetric immunoassays
Assignee: Texas A&M University System
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Filing: 1984-11-28
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Granted: 1988-04-05
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Expires: 2004-11-28
Abstract
Abstract A sensor and method for performing immunoassays using surface acoustic waves on a piezoelectric crystal is provided. A specific antigen or antibody is bonded to the surface of the piezoelectric crystal and its resonant frequency in a blank solution is determined. The sensor is then exposed to a test solution containing an antigen or antibody corresponding to the substance bonded to the surface of the crystal. As the antigen and antibody react, the resonant frequency of the crystal is altered. This change can be correlated to determine the amount of antigen or antibody in the test solution. A nonreactive reference sensor can also be used to compensate for any nonselective adsorption.
Inventors
- 👤 Glenn J. Bastiaans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:37
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/02; G01N29/022; G01N33/00; G01N33/48; G01N33/50; G01N33/53; G01N33/543; G01N33/54366; G01N33/54373; G01N2291/00; G01N2291/02; G01N2291/025; G01N2291/0256; G01N2291/04; G01N2291/042; G01N2291/0423; G01N2291/0426; Y; Y10; Y10S; Y10S436/00; Y10S436/806
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
101 words
A method for performing immunoassays, said method comprising the steps of: measuring in a blank solution the resonant frequency of a piezoelectric crystal having an antibody or antigen bonded to the surface thereof; exposing said antibody or antigen on said crystal to a test solution containing an antigen or antibody corresponding to said bonded antibody or antigen for a period such that the antigen can bind with the corresponding antibody so as to increase the mass on the surface of the crystal; and measuring in said test solution the resonant frequency of the piezoelectric crystal and determining the change in frequency.
Claim 2
Independent Claim
101 words
A method for performing immunoassays, said method comprising the steps of: measuring in a blank solution the resonant frequency of a piezoelectric crystal having an antibody or antigen bonded to the surface thereof; exposing said antibody or antigen on said crystal to a test solution containing an antigen or antibody corresponding to said bonded antibody or antigen for a period such that the antigen can bind with the corresponding antibody so as to increase the mass on the surface of the crystal; and measuring in said test solution the resonant frequency of the piezoelectric crystal and determining the change in frequency.
Claim 3
Dependent Claim
71 words
A method for performing immunoassays as defined in claim 1, further comprising: measuring in a blank solution the resonant frequency of a reference piezoelectric crystal and ratioing said reference frequency with the frequency of the indicator crystal; exposing the reference crystal to the test solution; and measuring in said test solution the resonant frequency of the reference crystal after exposure and ratioing said frequency with the frequency of the indicator crystal.
Claim 4
Dependent Claim
20 words
A method for performing immunoassays as defined in claim 1, further comprising comparing the frequency change to a standard curve.
Claim 5
Dependent Claim
20 words
A method for performing immunoassays as defined in claim 1, wherein the resonant frequency is determined using surface acoustic waves.
Claim 6
Dependent Claim
20 words
A method for performing immunoassays as defined in claim 2, wherein the resonant frequencies are determined using surface acoustic waves.
Claim 7
Dependent Claim
58 words
A sensor for performing immunoassays comprising: an indicator piezoelectric crystal having a specific antigen or antibody bonded to a portion of the surface thereof; means for forming surface acoustic waves on said crystal such that said waves pass through said antigen or antibody; and means for determining the resonant frequency of the surface acoustic waves on said crystal.
Claim 8
Dependent Claim
58 words
A sensor for performing immunoassays comprising: an indicator piezoelectric crystal having a specific antigen or antibody bonded to a portion of the surface thereof; means for forming surface acoustic waves on said crystal such that said waves pass through said antigen or antibody; and means for determining the resonant frequency of the surface acoustic waves on said crystal.
Claim 9
Dependent Claim
18 words
A sensor for performing immunoassays as defined in claim 6, wherein said piezoelectric crystal is a quartz crystal.
Claim 10
Dependent Claim
24 words
A sensor for performing immunoassays as defined in claim 6, wherein said antigen or antibody is covalently bonded to the surface of said crystal.
Claim 11
Dependent Claim
29 words
A sensor for performing immunoassays as defined in claim 6, wherein said antigen or antibody is bonded to a thin polymer film formed on the surface of said crystal.
Claim 12
Dependent Claim
22 words
A sensor for performing immunoassays as defined in claim 9, wherein said polymer film is less than about 5 monolayers in thickness.
Claim 13
Dependent Claim
18 words
A sensor for performing immunoassays as defined in claim 9, wherein said polymer film is a siloxane polymer.
Claim 14
Dependent Claim
19 words
A sensor for performing immunoassays as defined in claim 9, wherein said polymer film is a modified polyacrylamide polymer.
Claim 15
Dependent Claim
18 words
A sensor for performing immunoassays as defined in claim 9, wherein said polymer film exhibits minimal nonspecific adsorption.
Claim 16
Independent Claim
75 words
An apparatus for performing immunoassays comprising: a first indicator sensor comprising a piezoelectric crystal having a specific antigen or antibody bonded to a portion of the surface thereof; a reference sensor comprising a piezoelectric crystal adapted such that it is substantially nonreactive with antigens and antibodies; means for creating surface acoustic waves on said indicator sensor and said reference sensor; and means for measuring the resonant frequencies of said indicator sensor and said reference sensor.
Claim 17
Independent Claim
75 words
An apparatus for performing immunoassays comprising: a first indicator sensor comprising a piezoelectric crystal having a specific antigen or antibody bonded to a portion of the surface thereof; a reference sensor comprising a piezoelectric crystal adapted such that it is substantially nonreactive with antigens and antibodies; means for creating surface acoustic waves on said indicator sensor and said reference sensor; and means for measuring the resonant frequencies of said indicator sensor and said reference sensor.
Claim 18
Dependent Claim
25 words
A sensor as defined in claim 6 wherein said means for forming surface acoustic waves comprises a wave generator including a high gain RF amplifier.
Claim 19
Dependent Claim
17 words
A sensor as defined in claim 11 wherein the siloxane polymer is deposited by multiple bonding steps.
Claim 20
Dependent Claim
18 words
A sensor as defined in claim 16 wherein the multiple bonding steps comprise alternating aqueous and nonaqueous treatments.
Claim 21
Dependent Claim
19 words
An apparatus as defined in claim 14 wherein said sensors are positioned at the bottom of sample introduction wells.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-05 | 1991-10-05 | 1992-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-05 | 1995-10-05 | 1996-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-05 | 1999-10-05 | 2000-04-05 | $7700.00 | Window Closed / Lapsed |