Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving antigen-antibody binding – specific binding protein...
Reexamination Certificate
1998-06-04
2003-10-07
Chin, Christopher L. (Department: 1641)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving antigen-antibody binding, specific binding protein...
C422S051000, C422S068100, C422S082010, C422S082020, C422S082030, C422S082050, C422S082110, C422S083000, C422S098000, C422S119000, C422S186000, C427S211000, C427S212000, C204S403060, C204S406000, C204S412000, C204S416000, C204S431000, C204S222000, C435S007400, C435S007500, C435S007800, C435S287900
Reexamination Certificate
active
06630309
ABSTRACT:
FIELD OF THE INVENTION
The invention is generally in the field of biosensors, and concerns a sensor useful for the determination of the presence, and optionally also concentration, of an analyte in a liquid, particularly aqueous, medium. The present invention relates to such electrodes, as well as their use and systems comprising them.
PRIOR ART
In the following description, reference will be made to several prior art documents shown in the list of references below. The reference will be made by indicating their number from this list.
References
1. E. Engvall, in:
Methods in Enzymology
, Vol. 70, 1980, pp. 419-439.
2. A. Shons, F. Dorman, J. Najarian,
J. Biomed. Mater. Res.
6, 565 (1972).
3. A. A. Suleiman and G. G. Guilbault,
Analyst
, 119, 2279 (1994).
4. M. D. Ward and D. A. Buttry,
Science,
249, 1000 (1990).
5. J. R. Oliveria and S. F. Silver, U.S. Pat. No. 4,242,096 (1980).
6. T. K. Rice, U.S. Pat. No. 4,236,893 (1980).
7. T. K. Rice, U.S. Pat. No. 4,314,821 (1982).
8. J. E. Roederer, G. J. Bastiaans,
Anal. Chem.,
55, 2333 (1983).
9. J. E. Roederer and G. J. Bastiaans, U.S. Pat. No. 4,735,906 (1988).
10. H. Muramatsu, J. M. Dicks, E. Tamiya and I. Karube,
Anal. Chem.,
59, 2760 (1987).
11. D. Mueller-Schulte and H. Laurs, CA. 1990, 112(7), 51807 g.
12. H. Muramatsu, K. Kajiwara, E. Tamiya and I. Karube,
Anal. Chim. Acta,
188, 257 (1986).
13. H. Muramatsu, Y., Watanabe, M. Hikuma, T. Ataka, I. Kubo, E. Tamiya and I. Karube,
Anal. Lett.,
22, 2155 (1989).
14. B. Konig and M. Grätzel,
Anal. Lett.,
26, 1567 (193).
15. M D. Ward and R. C. Ebersole, PCT Application, Application No. WO 89/09937.
16. R. C. Ebersole, R. P. Foss and M. D. Ward, PCT Application, Application No. WO/94/02852.
17. R. C. Ebersole and J. R. Moran, PCT Application, Application No. WO/91/05251.
18. N. J. Geddes, E. M. Paschinger, D. N. Furlong, F. Caruso, C. L. Foffmann and J. F. Rabolt,
Thin Solid Films,
260:192-199 (1995).
19. I. Willner, S. Rubin and Y. Cohen,
J. Amer. Chem. Soc.,
115:4937-4938, (1993).
20. I. Willner, R. Blonder and A. Dagan,
J. Amer. Chem. Soc.,
116:9365-9366, (1994).
Mention of the above references in this writing does not mean to imply that these references are in any way relevant to the issue of patentability of the invention as defined in the appended claims.
BACKGROUND OF THE INVENTION
The specificity of antigen-antibody binding interactions and the technological progress in eliciting monoclonal antibodies for low molecular weight materials provide the grounds to design sensitive immunosensor devices for clinical diagnostics, food control and environmentally polluting substances. The most extensively developed immunosensor analyses include radioisotopic antigen/Ab labels and enzyme-linked immunosorbant assays (ELISA)
(1)
.
The discovery of a linear relationship between the change in the oscillating frequency of a piezoelectric crystal and the mass variation on the crystal as a result of binding or adsorption phenomena opened the possibilities to monitor gravimetrically antigen-antibody binding phenomena. The mathematical relation between the frequency changes of a piezoelectric crystal, &Dgr;f, and mass changes, &Dgr;m, on the crystal is given by the following Sauerbrey equation:
&Dgr;
f
=−2.3×10
6
f
o
2
·&Dgr;m/A
where f
o
is the fundamental resonance frequency of the crystal prior to the mass variation and A is the surface area of deposited mass. For example, for a crystal exhibiting a fundamental frequency of 9 MHz and surface area of 1 cm
2
, a mass-change on the crystal that corresponds to 1×10
−9
g will stimulate a frequency change, &Dgr;f, of 6 Hz.
The first analytical use of piezoelectric crystals in relation to antigen-antibody (Ag—Ab) interactions was reported in 1972
(2)
, where a nyebar precoated crystal was further coated via hydrophobic interactions, with bovine serum albumin (BSA) and the association of the BSA—Ab to the crystal was monitored by the frequency changes. Since then, the piezoelectric detection of antigens and antibodies by piezoelectric means or the quartz crystal microbalance (QCM) has been adopted in a series of analytical studies. The progress in this area has been reviewed by Suleiman et al., 1994
(3)
and Ward et al., 1990
(4)
. Immobilization of an antibody on a QCM device has been described by Geddes et al.
(18)
.
Several patents describe the application of QCM for the analysis of antigens and antibodies. Physical adsorption of antigens to a crystal was used as a means for the detection of antigens by interacting the crystal with a mixture of the analyte antigen and a predetermined amount of Ab
(5)
. The decrease in the antigen concentration was inversely related to the antigen concentration in the sample. In two patents by Rice
(6,7)
, methods for the determination of Abs by QCM were disclosed. The antigen was immobilized on a polymer precoated crystal and the frequency changes as a result of Ab association related to the analyte Ab concentration in the sample. By this method, human IgG against honey bee venom, phospholipase A, and keyhole limpet hemocyanine were analyzed
(6)
. However, non-specific binding to the crystal interfered with the analyses. In a follow-up patent
(7)
, the detection of low molecular weight components by a pre-coated crystal with the anti-Ab and competitive binding assay of the Ab-low molecular weight analyte was described. All of these analyses were performed by treatment of the crystals in solution and subsequent frequency measurements in air. This two-step solution/gas procedure allows improvement of the sensitivity of the resonating QCM, but introduces technical complications and the interference of hydration/dehydration phenomena that are reflected in the frequency parameters. Ward et al.
(15)
and Ebersole et al.
(17)
disclose a QCM assay where the sensitivity is increased by the use of an enzyme comprising conjugates which binds to the analyte after the latter has been bound to a capturing agent, which enzyme catalyzes a reaction where a substrate is converted to the product and the product which is absorbed on the QCM increases the mass of the QCM which gives rise to a change in its resonance frequency. Ebersole et al.
(16)
discloses a method that makes use of a polymer which changes its mass in the presence of an analyte, e.g. H
+
ions (serving as a pH) sensor.
Piezoelectric immunoassaying in the liquid phase has important technical advantages as it allows stationary and flow analysis of aqueous samples. The method suffers, however, from a basic physical limitation due to substantially lower frequency changes of the crystal as a result of the solution viscosity. QCM immunoassays in solution were reported by Roederer
(8)
and addressed in a follow-up patent
(9)
. The quartz crystal was modified with glycidoxypropyltrimethoxy silane (GOPS), and the surface-modified crystal was then further modified by anti-human IgG antibody and then applied for the piezoelectric detection of human IgG. The detection limit of the device was determined to be 13 &mgr;g·ml
−1
. A closely related approach was adopted by Muramatsu et al.
(10)
where the quartz crystals were surface-modified by &ggr;-aminopropyl triethoxy silane and further derivatized by protein A. The surface-modified crystals were then applied for the determination of human IgG in the concentration range 10
−6
-10
−2
mg·ml
−1
. A related patent disclosed the piezoelectric analysis of thyroxine using a polyamide 6 polymer coating and anti-thyroxine Ab as sensing interface
(11)
.
Piezoelectric analysis of high molecular weight antigens such as microbial cells was addressed using antibody-coated quartz crystals.
C. albicans
cells in the concentration range 1×10
6
-5×10
8
cells·ml
−1
were analyzed by an anti-
Candida albicans
Ab surface (12),
E. coli
with an anti-
E. coli
interface
(13)
and protein A-coated crystals acted as piezoelectric sensing interface for various bacteria including Salmonella, Shigella, Yersinia and
E. Coli
(14)
.
Use of photoisom
Cohen Yael
Dagan Arie
Katz Eugenii
Levi Shlomo
Willner Itamar
Biosensor Applications Sweden AB
Browdy and Neimark PLLC
Chin Christopher L.
Do Pensee
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