Patent US4336337A successfully refreshed from Google Patents.
US4336337A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detection of bacteria
Assignee: Baylor College of Medicine
•
Filing: 1980-06-16
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Granted: 1982-06-22
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Expires: 2000-06-16
Abstract
Abstract A test substrate, including a semi-permeable membrane which retains bacteria on the membrane and which has a net positive surface charge to permit coloring of bacteria thereon with a cationic dye, without the membrane adsorbing substantial amounts of said dye. Substrate is included in a kit for detecting bacteria.
Inventors
- 👤 Craig Wallis
- 👤 Joseph L. Melnick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:12
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/02; C12Q1/04; Y; Y10; Y10S; Y10S435/00; Y10S435/81
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
132 words
A kit for detecting bacteria, comprising: (a) a cationic dye for staining bacteria at a pH of above 7.0; (b) a chelating agent effective at a pH of above 7.0; (c) an acid decolorizing wash at a pH of from 2.7 to 4.0; and (d) a test substrate, said test substrate including a semi-permeable membrane which permits a test sample including bacteria to flow therethrough and which has a pore size to retain bacteria in the sample on the membrane for coloring thereon, said semi-permeable membrane having a net positive electrostatic surface charge to permit coloring of bacteria thereon with a cationic dye, without the membrane absorbing substantial amounts of said dye, the substrate including color differentiating indicia for providing a reading of bacterial concentration corresponding to color retained on the membrane.
Claim 2
Dependent Claim
132 words
A kit for detecting bacteria, comprising: (a) a cationic dye for staining bacteria at a pH of above 7.0; (b) a chelating agent effective at a pH of above 7.0; (c) an acid decolorizing wash at a pH of from 2.7 to 4.0; and (d) a test substrate, said test substrate including a semi-permeable membrane which permits a test sample including bacteria to flow therethrough and which has a pore size to retain bacteria in the sample on the membrane for coloring thereon, said semi-permeable membrane having a net positive electrostatic surface charge to permit coloring of bacteria thereon with a cationic dye, without the membrane absorbing substantial amounts of said dye, the substrate including color differentiating indicia for providing a reading of bacterial concentration corresponding to color retained on the membrane.
Claim 3
Dependent Claim
14 words
The kit of claim 1 and further comprising a rust solvent for dissolving rust.
Claim 4
Dependent Claim
21 words
The kit of claim 1 wherein the test substrate is a card having an aperture, said semi-permeable membrane covering said aperture.
Claim 5
Dependent Claim
17 words
The kit of claim 3 wherein the semi-permeable membrane is essentially free of negative electrostatic surface charge.
Claim 6
Dependent Claim
13 words
The kit of claim 4 wherein the semi-permeable membrane is an epoxy-fiberglass membrane.
Claim 7
Dependent Claim
10 words
The kit of claim 4 wherein the dye is safranin-O.
Claim 8
Dependent Claim
15 words
The kit of claim 6 wherein the chelating agent is a salt of ethylenediaminetetraacetic acid.
Claim 9
Dependent Claim
15 words
The kit of claim 6 wherein the dye is chromatographically purified safranin-O dissolved in water.
Claim 10
Dependent Claim
15 words
The kit of claim 8 wherein the acid decolorizing wash is comprised of acetic acid.
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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) | 1985-06-21 | 1985-12-21 | 1986-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-21 | 1989-12-21 | 1990-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-21 | 1993-12-21 | 1994-06-22 | $7700.00 | Window Closed / Lapsed |