WO1996024043A1 - Method and apparatus for detecting labelled substances - Google Patents

Method and apparatus for detecting labelled substances Download PDF

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Publication number
WO1996024043A1
WO1996024043A1 PCT/SE1996/000110 SE9600110W WO9624043A1 WO 1996024043 A1 WO1996024043 A1 WO 1996024043A1 SE 9600110 W SE9600110 W SE 9600110W WO 9624043 A1 WO9624043 A1 WO 9624043A1
Authority
WO
WIPO (PCT)
Prior art keywords
fluorophore
wavelength
laser
excitation
light
Prior art date
Application number
PCT/SE1996/000110
Other languages
French (fr)
Inventor
Bengt-Göran Andersson
Original Assignee
Pharmacia Biotech Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pharmacia Biotech Ab filed Critical Pharmacia Biotech Ab
Priority to JP8523475A priority Critical patent/JPH10513556A/en
Priority to EP96902546A priority patent/EP0807248A1/en
Publication of WO1996024043A1 publication Critical patent/WO1996024043A1/en

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416Systems
    • G01N27/447Systems using electrophoresis
    • G01N27/44704Details; Accessories
    • G01N27/44717Arrangements for investigating the separated zones, e.g. localising zones
    • G01N27/44721Arrangements for investigating the separated zones, e.g. localising zones by optical means
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64Fluorescence; Phosphorescence
    • G01N21/6428Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
    • G01N2021/6439Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" with indicators, stains, dyes, tags, labels, marks
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64Fluorescence; Phosphorescence
    • G01N21/6402Atomic fluorescence; Laser induced fluorescence

Definitions

  • the present invention relates to a method for detecting substances which are labelled with a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm by excitation of the fluorophore by means of light from a laser, and detection of fluorescence emitted by the fluorophore; an apparatus for detecting substances which are labelled with a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm, comprising a laser for excitation of the fluorophore by means of laser light, and a photodetector for detection of fluorescence emitted by the fluorophore; and the use of a specific type of fluorophores for labelling substances to be detected, together with a specific laser for excitation of the fluorophore.
  • the dye Cy3 is a carbocyanine based dye including a reactive succinimidyl ester and having a light absorption maximum at a wavelength of 552 nm and a light emission maximum at a wavelength of 565 nm.
  • He-Ne lasers are certainly smaller than argon lasers but their output power is low, normally 0.1-5 m , which causes the excitation efficiency to become low.
  • He-Ne lasers and of argon lasers Another disadvantage of He-Ne lasers and of argon lasers is that their output power is not stable but fluctuates. Moreover, neither He-Ne lasers nor argon lasers can be pulsed, which can be desirable in certain applications, e.g. time resolved fluorescence measurement.
  • the object of the invention is, therefore, to define a laser for excitation of a fluorphore of the type mentioned in the introduction, which laser does not exhibit the above disadvantages but is suitable to be built into commercial electrophoresis apparatuses.
  • a frequency-doubled Nd.YAG laser emitting at a wavelength of 532 nm is selected for the excitation of the fluorophore.
  • the object according to the invention is also attained by the apparatus according to the invention in that the laser for the excitation of the fluorophore is a frequency- doubled Nd.YAG laser emitting at a wavelength of 532 nm.
  • the use according to the invention consists of the use of a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm for labelling substances to be detected, and a frequency-doubled Nd.YAG laser emitting at a wavelength of 532 nm for excitation of the fluorophore.
  • FIG. 1 schematically shows an embodiment of an apparatus according to the invention.
  • 1 generally denotes a laser which emits a laser beam 2 which via a mirror 3 is directed into a gel 4 through one of its lateral edges, which gel 4 is provided between two glass plates 5 and 6.
  • the gel 4 is included in an electrophoretic separation system, not shown in any detail, for separating substances which, according to the invention, are labelled with a flurophore, which has a light absorption maximum at a wavelength between 530 and 570 nm.
  • the fluorophore used in a preferred embodiment of the invention is the dye marketed under the trademark Cy3, mentioned in the introduction, and manufactured by Biological Detection Systems, Inc., Pittsburgh, PA, U.S.A..
  • the dye Cy3 is a carbocyanine based dye containing a reactive succinimidyl ester and having a light absorption maximum at a wavelength of 552 nm and a light emission maximum at a wavelength of 565 nm.
  • Tetramethylrhodamine having a light absorption maximum at a wavelength of 555 nm and a light emission maximum at a wavelength of 580 nm as well as lissamine rhodamine B having a light absorption maximum at a wavelength of 570 nm and a light emission maximum at a wavelength of 590 nm are two other examples of fluorophores that can be used. Both these fluorophores are available from the US company Molecular Probes, Inc., Oregon, U.S.A.. When the fluorophore labelled substances migrating along the gel 4 pass through the laser beam 2, the fluorophore is excited to emit fluorescence which is detected by means of a photodetector 7.
  • the excitation of a single fluorophore 8 in a single migration lane is schematically indicated, but it is to be understood that in a practical embodiment of the apparatus according to the invention, there are several, mutually parallel migration lanes in the gel 4 as well as a corresponding number of photodetectors 7.
  • laser 1 for excitation of the fluorophore a commercially available, frequency- doubled Nd:YAG laser emitting at a wavelength of 532 nm, is used, which laser, due to its small size, is well suited to be built into commercial gel electrophoresis apparatuses, particularly for separation of nucleic acid fragments.
  • This laser which can have an output power of 5-100 mW, emits green light with small fluctuations and can furthermore be pulsed.
  • fluorophore-laser combination By the fluorophore-laser combination according to the invention, a combination is obtained which, what concerns size and efficiency, is well suited to be used in commercial electrophoresis apparatuses, particularly for separation of nucleic acid fragments.

Abstract

In a method and an apparatus for detecting substances which are labelled with a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm by excitation of the fluorophore by means of light from a laser (1), and detection of light emitted by the fluorophore by means of a photodetector (7), a frequency-doubled Nd:YAG laser emitting at a wavelength of 532 nm is selected for the excitation of the fluorophore.

Description

METHOD AND APPARATUS FOR DETECTING LABELLED SUBSTANCES
TECHNICAL FIELD
The present invention relates to a method for detecting substances which are labelled with a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm by excitation of the fluorophore by means of light from a laser, and detection of fluorescence emitted by the fluorophore; an apparatus for detecting substances which are labelled with a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm, comprising a laser for excitation of the fluorophore by means of laser light, and a photodetector for detection of fluorescence emitted by the fluorophore; and the use of a specific type of fluorophores for labelling substances to be detected, together with a specific laser for excitation of the fluorophore.
BACKGROUND OF THE INVENTION As a fluorophore for labelling substances to be detected, it is known to use a dye marketed under the trademark Cy3 and manufactured by Biological Detection Systems, Inc., Pittsburgh, PA, U.S.A..
The dye Cy3 is a carbocyanine based dye including a reactive succinimidyl ester and having a light absorption maximum at a wavelength of 552 nm and a light emission maximum at a wavelength of 565 nm.
To excite the dye Cy3, it is known to use argon lasers and He-Ne lasers. Argon lasers are, however, bulky, expensive and power demanding and, therefore, are not suitable to be built into commercial electrophoresis apparatuses.
He-Ne lasers are certainly smaller than argon lasers but their output power is low, normally 0.1-5 m , which causes the excitation efficiency to become low.
Another disadvantage of He-Ne lasers and of argon lasers is that their output power is not stable but fluctuates. Moreover, neither He-Ne lasers nor argon lasers can be pulsed, which can be desirable in certain applications, e.g. time resolved fluorescence measurement.
BRIEF DESCRIPTION OF THE INVENTION
The object of the invention is, therefore, to define a laser for excitation of a fluorphore of the type mentioned in the introduction, which laser does not exhibit the above disadvantages but is suitable to be built into commercial electrophoresis apparatuses.
This is attained by the method according to the invention in that a frequency-doubled Nd.YAG laser emitting at a wavelength of 532 nm, is selected for the excitation of the fluorophore. The object according to the invention is also attained by the apparatus according to the invention in that the laser for the excitation of the fluorophore is a frequency- doubled Nd.YAG laser emitting at a wavelength of 532 nm. The use according to the invention consists of the use of a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm for labelling substances to be detected, and a frequency-doubled Nd.YAG laser emitting at a wavelength of 532 nm for excitation of the fluorophore.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be described more in detail below with reference to the appended drawing on which the single figure, Fig. 1, schematically shows an embodiment of an apparatus according to the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
1 generally denotes a laser which emits a laser beam 2 which via a mirror 3 is directed into a gel 4 through one of its lateral edges, which gel 4 is provided between two glass plates 5 and 6.
The gel 4 is included in an electrophoretic separation system, not shown in any detail, for separating substances which, according to the invention, are labelled with a flurophore, which has a light absorption maximum at a wavelength between 530 and 570 nm.
The fluorophore used in a preferred embodiment of the invention, is the dye marketed under the trademark Cy3, mentioned in the introduction, and manufactured by Biological Detection Systems, Inc., Pittsburgh, PA, U.S.A.. The dye Cy3 is a carbocyanine based dye containing a reactive succinimidyl ester and having a light absorption maximum at a wavelength of 552 nm and a light emission maximum at a wavelength of 565 nm.
Tetramethylrhodamine having a light absorption maximum at a wavelength of 555 nm and a light emission maximum at a wavelength of 580 nm as well as lissamine rhodamine B having a light absorption maximum at a wavelength of 570 nm and a light emission maximum at a wavelength of 590 nm, are two other examples of fluorophores that can be used. Both these fluorophores are available from the US company Molecular Probes, Inc., Oregon, U.S.A.. When the fluorophore labelled substances migrating along the gel 4 pass through the laser beam 2, the fluorophore is excited to emit fluorescence which is detected by means of a photodetector 7.
On the drawing, the excitation of a single fluorophore 8 in a single migration lane is schematically indicated, but it is to be understood that in a practical embodiment of the apparatus according to the invention, there are several, mutually parallel migration lanes in the gel 4 as well as a corresponding number of photodetectors 7. According to the invention, as laser 1 for excitation of the fluorophore, a commercially available, frequency- doubled Nd:YAG laser emitting at a wavelength of 532 nm, is used, which laser, due to its small size, is well suited to be built into commercial gel electrophoresis apparatuses, particularly for separation of nucleic acid fragments.
This laser which can have an output power of 5-100 mW, emits green light with small fluctuations and can furthermore be pulsed. Another advantage of, in accordance with the invention, using a laser which emits green light in comparison to lasers which emit yellow or red light, is that a better geometric resolution is obtained in the applications in question since a green laser beam is narrower than both a red and a yellow laser beam.
By the fluorophore-laser combination according to the invention, a combination is obtained which, what concerns size and efficiency, is well suited to be used in commercial electrophoresis apparatuses, particularly for separation of nucleic acid fragments.

Claims

1. A method for detecting substances which are labelled with a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm by excitation of the fluorophore by means of light from a laser (1) , and detection of light emitted by the fluorophore, characterized in that a frequency-doubled Nd.YAG laser, emitting at a wavelength of 532 nm, is selected for the excitation of the fluorophore.
2. A method according to claim 2, particularly in a gel electrophoresis apparatus for separating nucleic acid fragments, characterized in that a carbocyanine based dye, marketed under the trademark Cy3, is selected as fluorophore.
3. An apparatus for detecting substances which are labelled with a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm, comprising a laser (1) for excitation of the fluorophore by means of laser light, and a photodetector (7) for detection of light emitted by the fluorophore, characterized in that the laser (1) for the excitation of the fluorophore is a frequency-doubled Nd.YAG laser emitting at a wavelength of 532 nm.
4. An apparatus according to claim 3, particularly in a gel electrophoresis apparatus for separating nucleic acid fragments, characterized in that the fluorophore is a carbocyanine based dye marketed under the trademark Cy3.
5. Use of a fluorophore having a light absorption maximum at a wavelength between 530 and 570 nm for labelling substances to be detected, and a frequency-doubled Nd.YAG laser (1) emitting at a wavelength of 532 nm for excitation of the fluorophore.
6. Use according to claim 5, particularly in a gel electrophoresis apparatus for separating nucleic acid fragments, wherein the fluorophore used is a carbocyanine based dye marketed under the trademark Cy3.
PCT/SE1996/000110 1995-02-01 1996-01-31 Method and apparatus for detecting labelled substances WO1996024043A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP8523475A JPH10513556A (en) 1995-02-01 1996-01-31 METHOD AND APPARATUS FOR DETECTING LABEL
EP96902546A EP0807248A1 (en) 1995-02-01 1996-01-31 Method and apparatus for detecting labelled substances

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9500360A SE9500360D0 (en) 1995-02-01 1995-02-01 Method and apparatus for detecting labeled substances
SE9500360-4 1995-02-01

Publications (1)

Publication Number Publication Date
WO1996024043A1 true WO1996024043A1 (en) 1996-08-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1996/000110 WO1996024043A1 (en) 1995-02-01 1996-01-31 Method and apparatus for detecting labelled substances

Country Status (4)

Country Link
EP (1) EP0807248A1 (en)
JP (1) JPH10513556A (en)
SE (1) SE9500360D0 (en)
WO (1) WO1996024043A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7439522B2 (en) 2005-03-04 2008-10-21 Hitachi High-Technologies Corporation Counting system for fluorescent molecules

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Vol. 17, No. 338, (P-1564), 25 June 1993; & JP,A,05 045 332 (HITACHI SOFTWARE ENG CO LTD), 23 February 1993. *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7439522B2 (en) 2005-03-04 2008-10-21 Hitachi High-Technologies Corporation Counting system for fluorescent molecules

Also Published As

Publication number Publication date
SE9500360D0 (en) 1995-02-01
JPH10513556A (en) 1998-12-22
EP0807248A1 (en) 1997-11-19

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