WO2002066574A1 - Fluorescent microparticles - Google Patents
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- WO2002066574A1 WO2002066574A1 PCT/DE2002/000556 DE0200556W WO02066574A1 WO 2002066574 A1 WO2002066574 A1 WO 2002066574A1 DE 0200556 W DE0200556 W DE 0200556W WO 02066574 A1 WO02066574 A1 WO 02066574A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
- G01N33/543—Immunoassay; Biospecific binding assay; Materials therefor with an insoluble carrier for immobilising immunochemicals
- G01N33/54313—Immunoassay; Biospecific binding assay; Materials therefor with an insoluble carrier for immobilising immunochemicals the carrier being characterised by its particulate form
- G01N33/54346—Nanoparticles
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
- C09K11/025—Use of particular materials as binders, particle coatings or suspension media therefor non-luminescent particle coatings or suspension media
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
- G01N33/531—Production of immunochemical test materials
- G01N33/532—Production of labelled immunochemicals
- G01N33/533—Production of labelled immunochemicals with fluorescent label
Definitions
- the invention relates to fluorescent microparticles which in the core consist of polymer particles with incorporated dyes or semiconductor crystals and are coated with metallic conductive material, furthermore a method for producing these microparticles and applications of these microparticles in analytics, in particular in biology and medicine.
- the microparticles according to the invention are notable for improved photostability and higher fluorescence intensity (fluorescence brightness).
- Fluorescent microparticles are known from the literature and have found a wide range of applications in analysis, particularly in the detection of biologically relevant materials.
- EP 0 596 098 describes fluorescent microparticles in which fluorescent dyes are embedded in polymers and used appropriately in biological analysis. Analogous materials are also mentioned in USP 2,994,679 and USP 3,096,333.
- Such fluorescent microparticles are used in a wide range of applications in biology and medicine, since biologically active materials can be chemically or physically adsorptively attached to their surface. In this way, the fluorescent microparticles serve as markers or tracers for the detection of the biological material. Blood flow measurements using such microparticles are described in Circulation 83, 974 (1991). In J. Microbiol. Meth. 13, 135, (1991) the behavior of bacteria is examined. Further examples are the use in immunoassays (Anal. Biochem. 272, 165, (1999)) and nucleic acid analysis (Anal. Biochem. 198, 308, (1991), Nucleic Acid Res. 15, 2891, (1987)). A summary of applications can be found in: R.P. Haughland: Handbook of Fluorescent Probes and Research Chemicals, 7th Edition Molecular Probes, 1999.
- the object of the invention is therefore to find fluorescent microparticles with significantly improved fluorescence brightness and photostability, which allow the use of highly sensitive detection methods with simple means, and to specify methods for their production and use.
- the fluorescent microparticles according to the invention contain a core of a fluorescent material which consists of polymer particles which are loaded with organic dyes or of semiconductor microcrystals. These fluorescent core particles are coated with a material that is metallically conductive at the optical frequencies of the excitation and fluorescence. Depending on the diameter of the fluorescent core, the type of metallically conductive material and its layer thickness, the intensity of the emitted fluorescent light and / or the photostability of the dyes located in the core are significantly increased. This remarkable improvement in fluorescence properties occurs with both single-photon and multi-photon imaging.
- this improvement in the fluorescence properties depends on the type of metallically conductive material, the diameter of the core and the layer thickness of the metal applied. It was found that gold, silver, copper or aluminum are particularly suitable.
- the diameter of the fluorescent core is preferably in the range from 10 to 90 nm and the layer thickness of the metallically conductive material is preferably 1 to 10 nm. If silver is used as the metallically conductive material, the particularly preferred diameter of the core is 10 to 50 nm.
- the core of the fluorescent microparticles consists of semiconductor material, such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, InP, InAs.
- Suitable fluorescent organic dyes are dyes from the classes of coumarins, oxazines, thiazines, rhodamines, dibenzpyrans, polymethines such as cyanines, phthalocyanines or combinations thereof.
- dyes are introduced into polymer material, for which purpose polymers or copolymers of styrene, divinylbenzene, acrylonitrile or methacrylonitrile, acrylamide or methacrylamide, acrylic or methacrylic acid esters, maleic acid derivatives, vinyl acetate, vinyl chloride, furthermore cellulose derivatives, agarose, polyurethane acid, polyhydroxybutylene , Polylactides are suitable.
- Crosslinked polymers with anion or cation exchange groups are also suitable.
- the metallically coated fluorescent microparticles are advantageously coated with a protective layer of oxides or sulfides.
- polysulfides or other substances containing thiol groups are also suitable.
- the metallized microparticles can also be coated with protein bodies such as albumin by adsorption. In this way and by coating with other substances or chemical reaction, the microparticles receive functional coupling groups such as hydroxyl, amine, A id, imide, carboxylic anhydride, sulfhydryl, sulfonate, aldehyde, azide, quinone azide.
- Biotin, avidin, streptavidin or nucleic acid compounds can also be attached to these functional groups or by prior coating.
- the fluorescent microparticles according to the invention are suitable for a large number of analytical applications.
- the fluorescent microparticles according to the invention are produced in several directions.
- hydrophobic dyes which are practically insoluble in water are combined with the polymer which is also insoluble in water.
- Dissolve material in an organic solvent which is also miscible with water Solvents are used whose boiling point is lower than that of water.
- methylene chloride, chloroform, dichloroethane, carbon tetrachloride, trichlorethylene, benzene, cyclohexane are suitable.
- Polymers or copolymers of styrene, divinylbenzene, acrylonitrile or methacrylonitrile, acrylic or methacrylic acid esters, maleic acid derivatives, vinyl acetate, vinyl chloride, furthermore water-insoluble cellulose derivatives, polyurethane, polyhydroxybutyric acid, polylactides, polyvinyl alcohol, gelatin, agarose are used as the polymer material.
- surfactants as emulsifying agents which can be carried out both to the organic and to the aqueous phase or to both phases, the two phases are mixed intensively using a high-speed stirrer, so that a finely divided emulsion is formed.
- the droplets of the solvent which contain the polymer material and the dye, are finely divided in the continuous water phase. After the solvent has been distilled off, these droplets solidify into spheroidal microparticles. These can e.g. isolated by centrifugation, washed and further processed accordingly.
- core particles which contain hydrophilic polymers such as agarose, polyacrylamide, water-soluble cellulose derivatives, polyvinyl alcohol, gelatin and hydrophilic dyes.
- the polymers and the dyes are dissolved in water and this solution is emulsified again using surfactants in an organic solvent whose boiling point is above the boiling point of water.
- an organic solvent whose boiling point is above the boiling point of water.
- toluene, ethylbenzene, xylenes, Cu ol are suitable for this.
- a finely divided emulsion with the organic solvent is obtained as a continuous phase.
- the polymer material and the dyes are in the finely divided water drops. After the water has been distilled off, these droplets solidify into spheroidal microparticles. These are isolated again by centrifugation.
- polymeric microparticles which contain anion- or cation-exchanging groups on their surface such as appropriately modified styrene-divinyl copolymers, can also be loaded with ionic dyes.
- these fluorescent core particles are coated with a material that is metallically conductive at the optical frequencies of excitation and fluorescence.
- Gold, silver, copper or aluminum are particularly suitable for this.
- certain layer thicknesses in the range from 1 to 10 nm are particularly preferred in order to achieve maximum photostability and / or fluorescence intensity.
- This improvement in fluorescence properties according to the invention depends in a complex manner on the material properties of the substances involved (polymer material and dyes), type of metallically conductive material, the geometric relationships (diameter of the core particles and layer thickness of the metallically conductive material) and the type of excitation and emission (a - or multi-photon excitation).
- the fluorescent core particles are coated by dispersing these particles in a solvent, preferably in an aqueous medium, adding a salt or another compound of the metallically conductive material and a reducing agent.
- Suitable metal salts are, for example, silver sulfate, silver nitrate, gold (HI) chloride, gold (I) cyanide, copper sulfate, copper nitrate.
- a large number of reducing agents are suitable for silver or gold.
- the following list represents a selection without claim to completeness: formaldehyde, iron (II) sulfate, tartaric acid, hydroquinone, p-aminophenol, dialkylaniline, phenidone, sulfite, oxalic acid, sugar, tartaric acid, citric acid.
- Solutions of the metal salts and the reducing agent are expediently added alternately in small portions to the dispersed core particles and samples are taken. to track and control the coating process. The samples taken are examined for their fluorescence properties in comparison to the uncoated core particles.
- the thickness of the coating is determined by detaching the metal layer from a defined number of microparticles and analytically determining the metal ion concentration. For example, polarography or atomic absorption spectroscopy are used for this.
- Layer thicknesses of the metallically conductive material in the range from 1 to 10 nm and fluorescent core particles with a diameter of 10 to 90 nm have proven to be suitable. Core particles with a diameter of 10 to 50 nm are particularly suitable if silver is used as the metallic conductive material.
- the surface of the metallized particles can be modified in order to bring about the coupling in particular of biologically or medically relevant substances.
- the surface of the metallized particles can be modified in order to bring about the coupling in particular of biologically or medically relevant substances.
- treatment with oxidizing agents or ammonium sulfide solutions creates a thin protective layer on the metallized surfaces.
- Aliphatic polysulfides or monomeric substances containing thiol groups are also suitable for this.
- biomaterials In order to enable the further coupling of biomaterials, they can be coated with protein bodies such as albumin or other substances which contain functional groups.
- protein bodies such as albumin or other substances which contain functional groups.
- a large number of monomeric or polymeric substances such as styrene / maleic acid copolymers, polyvinyl alcohol and polyvinyl alcohol derivatives, soluble cellulose derivatives, azides, diazides, quinonediazides are suitable as coating material.
- the fluorescent microparticles can be equipped with functional groups such as hydroxyl, amine, amide, imide, carboxylic anhydride, sulfhydryl, sulfonate, aldehyde, azide, quinone azide or biologically active substances.
- the coating with or coupling of biotin, avidin, streptavidin or nucleic acid compounds is particularly attractive for use in bioanalytics.
- the fluorescent microparticles according to the invention are used as fluorescent markers or tracers.
- the use as a fluorescence marker uses the possibility that the functional groups or biologically active substances bound to the microparticles react with analyte substances and can subsequently be detected by means of a fluorescence measurement.
- the usual procedure is as follows: a) A sample is prepared in which the analyte substances to be detected are located. b) Fluorescent microparticles equipped with functional groups or biologically active substances which are capable of recognizing the analyte substances are dispersed or applied in a suitable manner to a surface. c) The analyte substances and the fluorescent microparticles are brought together and incubated for the required reaction time. d) Microparticles that have not reacted are removed. e) The bound microparticles and thus the analyte substances are irradiated and detected using the emitted fluorescent light.
- Proteins, peptides, DNA, RNA, oligonucleotides, polysaccharides, avidin, biotin, polymeric and non-polymeric biomolecules, antibodies, antigens, viruses or other microorganisms can be detected according to this scheme.
- the method described can also be specifically designed as an immunoassay.
- the detection of DNA, RNA or oligonucleotides can be used in DNA sequence analysis.
- Cells labeled with fluorescent microparticles can be sorted out or cytometrically detected.
- the fluorescent microparticles according to the invention can also be used as tracers for examining transport processes in fluid media inside and outside of living organisms or cells.
- the high fluorescence intensity of the microparticles according to the invention with two-photon excitation allows excitation with inexpensive commercial diode lasers in the range 600-1100 nm and the detection of the short-wave fluorescence radiation emitted in the range 300-700 nm. Because of the high fluorescence intensity and the improved photo stability, the Microparticles according to the invention in many cases make the detection method simpler and more economical. For example, the detection of the fluorescent microparticles is also possible with a CCD camera.
- Solution A 2% solution of silver nitrate in double distilled water
- Solution B 2g p-aminophenol and 10g potassium carbonate are dissolved in 250 ml double distilled water
- the amount of silver deposited on the ponds is determined.
- the silver is oxidatively dissolved in a potassium ferricyanide solution and determined by polarography.
- Example 1 the coating of microparticles with gold and the determination of the fluorescence properties of the particles obtained with single-photon excitation at the wavelength 635 nm and emission at 670 nm are described as in Example 1.
- 1 g of the dye-loaded polystyrene microparticles are dispersed analogously to Example 1 in 250 ml of double-distilled water and the following solutions are prepared: Solution A: 3% solution of tetrachloroauric acid trihydrate in 11 double-distilled water
- Solution B 2.5% solution of potassium carbonate in 11 double-distilled water
- Solution C 3 ml 37% formaldehyde solution dissolved in 11 double-distilled water
- Example 3 describes the determination of the fluorescence properties for two-photon excitation.
- the starting material used was polystyrene microparticles with a diameter of 50 nm, which were loaded with the dye rhodamine 6G.
- the coating of these microparticles with silver or gold was carried out analogously to Example 1 and Example 2.
- a pulsed diode laser pulse repetition rate 80 MHz, pulse width 50 ps was excited at the wavelength of 790 nm and the fluorescence emission at wavelengths in the range of 450 - 600 nm measured.
- the fluorescence intensity increased by a factor of 1000 compared to the non-metallized particles when measuring the fluorescent light at the wavelength of 460 nm.
- the photostability for these microparticles increased among the same measurement conditions by a factor of 2.
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Abstract
Description
Fluoreszierende MikroteilchenFluorescent microparticles
Die Erfindung betrifft fluoreszierende Mikroteilchen, die im Kern aus Polymerteilchen mit inkorporierten Farbstoffen oder aus Halbleiterkristallen bestehen und mit metallisch leitenden Material beschichtet sind, ferner ein Verfahren zur Herstellung dieser Mikroteilchen und Anwendungen dieser Mikroteilchen in der Analytik insbesondere in Biologie und Medizin. Die erfindungsgemaßen Mikroteilchen zeichnen sich durch verbesserte Photostabilität und höhere Fluoreszenzintensität (Fluoreszenzhelligkeit) aus.The invention relates to fluorescent microparticles which in the core consist of polymer particles with incorporated dyes or semiconductor crystals and are coated with metallic conductive material, furthermore a method for producing these microparticles and applications of these microparticles in analytics, in particular in biology and medicine. The microparticles according to the invention are notable for improved photostability and higher fluorescence intensity (fluorescence brightness).
Fluoreszierende Mikroteilchen sind aus der Literatur bekannt und haben ein breites Anwendungsgebiet in der Analytik besonders beim Nachweis biologisch relevanter Materialien gefunden. So werden in EP 0 596 098 fluoreszierende Mikropartikel beschrieben, bei denen Fluoreszenzfarbstoffe in Polymere eingebettet und entsprechend ausgerüstet in der biologischen Analytik eingesetzt werden. Analoge Materialien werden auch in USP 2 994 679 und USP 3 096 333 erwähnt.Fluorescent microparticles are known from the literature and have found a wide range of applications in analysis, particularly in the detection of biologically relevant materials. For example, EP 0 596 098 describes fluorescent microparticles in which fluorescent dyes are embedded in polymers and used appropriately in biological analysis. Analogous materials are also mentioned in USP 2,994,679 and USP 3,096,333.
Derartige fluoreszierende Mikroteilchen finden vielfältige Anwendungen in der Biologie und Medizin, da man an ihre Oberfläche biologisch aktive Materialien chemisch oder physikalisch adsorptiv anbinden kann. Auf diese Weise gelabeit, dienen die fluoreszierenden Mikropartikel als Marker oder Tracer für den Nachweis des biologischen Materials. So werden in Circulation 83, 974 (1991) Blutflußmessungen mit Hilfe derartiger Mikropartikel beschrieben. In J. Microbiol. Meth. 13, 135, (1991) wird das Verhalten von Bakterien untersucht. Weitere Beispiele sind die Anwendung in Immunoassays (Anal. Biochem. 272, 165, (1999)) und der Nucleinsäureanalytik (Anal. Biochem. 198, 308, (1991), Nucleic Acid Res. 15, 2891, (1987)). Eine zusammenfassende Darstellung von Anwendungen befindet sich in: R.P. Haughland: Handbook of Fluorescent Probes and Research Chemicals, 7. Aufl. Molecu- lar Probes, 1999.Such fluorescent microparticles are used in a wide range of applications in biology and medicine, since biologically active materials can be chemically or physically adsorptively attached to their surface. In this way, the fluorescent microparticles serve as markers or tracers for the detection of the biological material. Blood flow measurements using such microparticles are described in Circulation 83, 974 (1991). In J. Microbiol. Meth. 13, 135, (1991) the behavior of bacteria is examined. Further examples are the use in immunoassays (Anal. Biochem. 272, 165, (1999)) and nucleic acid analysis (Anal. Biochem. 198, 308, (1991), Nucleic Acid Res. 15, 2891, (1987)). A summary of applications can be found in: R.P. Haughland: Handbook of Fluorescent Probes and Research Chemicals, 7th Edition Molecular Probes, 1999.
Bekannt ist auch die Verwendung von Halbleitermikrokristallen mit Teilchengrößen im Nanometerbereich sogenannter Quantum Dots für den gleichen Anwendungszweck (WO 99/26 269, WO 00/17 642).It is also known to use semiconductor microcrystals with particle sizes in the nanometer range known as quantum dots for the same application (WO 99/26 269, WO 00/17 642).
Diese in der Literatur bisher beschriebenen fluoreszierenden Mikroteilchen haben jedoch mindestens zwei grundsätzliche Nachteile. Zum einen besitzen die inkorporierten Farbstoffe eine ungenügende Photostabilität und zum anderen ist die Intensität des emmittierten Fluoreszenzlichts (Helligkeit) oft ungenügend. Dadurch ist ihre Anwendung insbesondere bei hochsensitiven Messungen eingeschränkt. Beispielsweise muß ein sehr hoher apparativer Aufwand hinsichtlich der Lasertechnik und Elektronik bei der Anwendung der Mehrphotonenanregung, z.B. Zweiphotonenanregung, betrieben werden. Die Methode der Zweiphotonenanregung im langwelligen Bereich oberhalb von 600 nm und die Detektion des Fluoreszenzlichts kurzwellig ist besonders attraktiv, da bei dieser Meßmethode nur eine sehr geringe Untergrundstrahlung auftritt.However, these fluorescent microparticles previously described in the literature have at least two fundamental disadvantages. On the one hand, the incorporated dyes have insufficient photostability and, on the other hand, the intensity of the emitted fluorescent light (brightness) is often insufficient. This limits their application, particularly for highly sensitive measurements. For example, a very high expenditure on equipment with regard to laser technology and electronics when using the multi-photon excitation, e.g. Two-photon excitation can be operated. The two-photon excitation method in the long-wave range above 600 nm and the detection of the short-wave fluorescent light is particularly attractive, since only very little background radiation occurs with this measuring method.
Aufgabe der Erfindung ist es deshalb, fluoreszierende Mikroteilchen mit wesentlich verbesserter Fluoreszenzhelligkeit und Photostabilität, die den Einsatz hochempfindlicher Nachweisverfahren mit einfachen Mitteln gestatten, aufzufinden und Verfahren zu ihrer Herstellung und Verwendung anzugeben.The object of the invention is therefore to find fluorescent microparticles with significantly improved fluorescence brightness and photostability, which allow the use of highly sensitive detection methods with simple means, and to specify methods for their production and use.
Diese Aufgabe wird erfindungsgemäß durch fluoreszierende Mikroteilchen mit den Merkmalen des Anspruchs 1 bzw. Herstellungsverfahren nach Anspruch 21 und Verwendung nach Anspruch 28 gelöst. Nachfolgend wird die Erfindung näher erläutert. Die erfindungsgemaßen fluoreszierenden Mikroteilchen enthalten einen Kern eines fluoreszierenden Materials, der aus Polymerpartikeln, die mit organischen Farbstoffen beladen sind oder aus Halbleitermikrokristallen, besteht. Diese fluoreszierenden Kernteilchen werden mit einem bei den optischen Frequenzen der Anregung und Fluoreszenz metallisch leitenden Material beschichtet. In Abhängigkeit vom Durchmesser des fluoreszierenden Kerns, der Art des metallisch leitenden Materials und dessen Schichtdicke werden die Intensität des abgestrahlten Fluoreszenzlichts und/oder die Photostabilität, der im Kern befindlichen Farbstoffe wesentlich erhöht. Diese bemerkenswerte Verbesserung der Fluoreszenzeigenschaften tritt sowohl bei Einphotonen- als auch bei Mehr- photonennaregung auf. Im Detail hängt diese Verbesserung der Fluoreszenzeigenschaften von der Art des metallisch leitenden Materials, dem Durchmesser des Kerns und der Schichtdicke des aufgebrachten Metalls ab. So wurde gefunden, daß Gold, Silber, Kupfer oder Aluminium sich besonders gut eignen. Der Durchmesser des fluoreszierenden Kerns liegt bevorzugt im Bereich von 10 bis 90 nm und die Schichtdicke des metallisch leitenden Materials beträgt bevorzugt 1 bis 10 nm. Verwendet man Silber als metallisch leitendes Material, so ist der besonders bevorzugte Durchmesser des Kerns 10 bis 50 nm. Die gleichen Effekte der Verbesserung der Fluoreszenzeigenschaften treten auch auf, wenn der Kern der fluoreszierenden Mikroteilchen aus Halbleitermaterial, wie CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, InP, InAs besteht.This object is achieved according to the invention by fluorescent microparticles having the features of claim 1 or the production method according to claim 21 and use according to claim 28. The invention is explained in more detail below. The fluorescent microparticles according to the invention contain a core of a fluorescent material which consists of polymer particles which are loaded with organic dyes or of semiconductor microcrystals. These fluorescent core particles are coated with a material that is metallically conductive at the optical frequencies of the excitation and fluorescence. Depending on the diameter of the fluorescent core, the type of metallically conductive material and its layer thickness, the intensity of the emitted fluorescent light and / or the photostability of the dyes located in the core are significantly increased. This remarkable improvement in fluorescence properties occurs with both single-photon and multi-photon imaging. In detail, this improvement in the fluorescence properties depends on the type of metallically conductive material, the diameter of the core and the layer thickness of the metal applied. It was found that gold, silver, copper or aluminum are particularly suitable. The diameter of the fluorescent core is preferably in the range from 10 to 90 nm and the layer thickness of the metallically conductive material is preferably 1 to 10 nm. If silver is used as the metallically conductive material, the particularly preferred diameter of the core is 10 to 50 nm The same effects of improving the fluorescence properties also occur if the core of the fluorescent microparticles consists of semiconductor material, such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, InP, InAs.
Als fluoreszenzfähige organische Farbstoffe eignen sich Farbstoffe aus den Stoffklassen der Cumarine, Oxazine, Thiazine, Rhodamine, Dibenzpyrane, Polymethine wie Cyanine, Phtha- locyanine oder Kombinationen davon.Suitable fluorescent organic dyes are dyes from the classes of coumarins, oxazines, thiazines, rhodamines, dibenzpyrans, polymethines such as cyanines, phthalocyanines or combinations thereof.
Diese Farbstoffe werden in Polymermaterial eingebracht, wofür sich Polymere oder Copoly- mere von Styrol, Divinylbenzol, Acrylnitril oder Methacrylnitril, Acrylamid oder Methacry- lamid, Acrylsäure- oder Methacrylsäureester, Maleinsäurederivaten, Vinylacetat, Vinylchlo- rid, ferner Cellulosederivate, Agarose, Polyurethan, Polyhydroxybuttersäure, Polylactide eignen.These dyes are introduced into polymer material, for which purpose polymers or copolymers of styrene, divinylbenzene, acrylonitrile or methacrylonitrile, acrylamide or methacrylamide, acrylic or methacrylic acid esters, maleic acid derivatives, vinyl acetate, vinyl chloride, furthermore cellulose derivatives, agarose, polyurethane acid, polyhydroxybutylene , Polylactides are suitable.
Geeignet sind ebenfalls vernetzte Polymere mit anionen- oder kationenaustauschenden Gruppen.Crosslinked polymers with anion or cation exchange groups are also suitable.
Vorteilhaft werden die metallisch beschichteten fluoreszierenden Mikroteilchen mit einer Schutzschicht aus Oxiden oder Sulfiden überzogen. Geeignet sind aber auch Polysulfide oder andere thiolgruppenenthaltende Substanzen. Gleichfalls können die metallisierten Mikroteilchen mit Eiweißkörpern wie Albumin adsorptiv beschichtet werden. Auf diese Weise und durch Beschichtung mit anderen Substanzen oder chemische Reaktion erhalten die Mikroteilchen funktionelle Kopplungsgruppen wie Hydroxyl, Amin, A id, Imid, Carbonsäureanhydrid, Sulfhydryl, Sulfonat, Aldehyd, Azid, Chinonazid.The metallically coated fluorescent microparticles are advantageously coated with a protective layer of oxides or sulfides. However, polysulfides or other substances containing thiol groups are also suitable. The metallized microparticles can also be coated with protein bodies such as albumin by adsorption. In this way and by coating with other substances or chemical reaction, the microparticles receive functional coupling groups such as hydroxyl, amine, A id, imide, carboxylic anhydride, sulfhydryl, sulfonate, aldehyde, azide, quinone azide.
An diese funktionelle Gruppen oder durch vorherige Beschichtung können auch biologisch aktive Substanzen wie Biotin, Avidin, Streptavidin, oder Nucleinsäureverbindungen angebracht werden.Biologically active substances such as biotin, avidin, streptavidin or nucleic acid compounds can also be attached to these functional groups or by prior coating.
Auf diese Weise mit einer chemisch aktiven Oberfläche ausgerüstet, eignen sich die erfindungsgemäßen fluoreszierenden Mikroteilchen für eine Vielzahl von analytischen Anwendungen.Equipped with a chemically active surface in this way, the fluorescent microparticles according to the invention are suitable for a large number of analytical applications.
Die Herstellung der erfindungsgemaßen fluoreszierenden Mikroteilchen erfolgt in mehrerenThe fluorescent microparticles according to the invention are produced in several
Schritten.Steps.
Im ersten Schritt werden die Kernteilchen mit einem mittleren Teilchendurchmesser von 5 bisIn the first step, the core particles with an average particle diameter of 5 to
100 nm, die aus mit Farbstoffen beladenen Polymerteilchen oder Halbleitermikrokristallen bestehen, präpariert.100 nm, which consist of polymer particles or semiconductor microcrystals loaded with dyes, prepared.
In einer Ausgestaltung des erfindungsgemäßen Verfahrens werden hydrophobe in Wasser praktisch unlösliche Farbstoffe gemeinsam mit dem ebenfalls in Wasser unlöslichen Poly- mermaterial in einem organischen mit Wasser ebenfalls nur beschränkt mischbaren Lösungsmittel gelöst. Dabei werden Lösungsmittel verwendet, deren Siedepunkt niedriger als der von Wasser ist. Geeignet sind beispielsweise Methylenchlorid, Chloroform, Dichlorethan, Tetrachlorkohlenstoff, Trichlorethylen, Benzol, Cyclohexan.In one embodiment of the process according to the invention, hydrophobic dyes which are practically insoluble in water are combined with the polymer which is also insoluble in water. Dissolve material in an organic solvent which is also miscible with water. Solvents are used whose boiling point is lower than that of water. For example, methylene chloride, chloroform, dichloroethane, carbon tetrachloride, trichlorethylene, benzene, cyclohexane are suitable.
Als Polymermaterial werden verwendet Polymere oder Copolymere von Styrol, Divinylben- zol, Acrylnitril oder Methacrylnitril, Acrylsäure-oder Methacrylsäureester, Maleinsäurederivaten, Vinylacetat, Vinylchlorid, ferner wasserunlösliche Cellulosederivate, Polyurethan, Po- lyhydroxybuttersäure, Polylactide, Polyvinylalkohol, Gelatine, Agarose. Nach Zugabe von grenzflächenaktiven Stoffen als Emulgierhilfsmittel, die sowohl zu der organischen als auch zu der wässrigen Phase oder zu beiden Phasen erfolgen kann, werden beide Phasen unter Anwendung eines hochtourigen Rührwerks intensiv vermischt, so daß sich eine feinteilige Emulsion bildet. In der kontinuierlichen Wasserphase feinverteilt befinden sich die Tröpfchen des Lösungsmittels, die das Polymermaterial und den Farbstoff enthalten. Nach Abdestillieren des Lösungsmittels verfestigen sich diese Tröpfchen zu sphäroiden Mikroteilchen. Diese können z.B. durch Zentrifugieren isoliert, gewaschen und entsprechend weiterverarbeitet werden.Polymers or copolymers of styrene, divinylbenzene, acrylonitrile or methacrylonitrile, acrylic or methacrylic acid esters, maleic acid derivatives, vinyl acetate, vinyl chloride, furthermore water-insoluble cellulose derivatives, polyurethane, polyhydroxybutyric acid, polylactides, polyvinyl alcohol, gelatin, agarose are used as the polymer material. After the addition of surfactants as emulsifying agents, which can be carried out both to the organic and to the aqueous phase or to both phases, the two phases are mixed intensively using a high-speed stirrer, so that a finely divided emulsion is formed. The droplets of the solvent, which contain the polymer material and the dye, are finely divided in the continuous water phase. After the solvent has been distilled off, these droplets solidify into spheroidal microparticles. These can e.g. isolated by centrifugation, washed and further processed accordingly.
Bei der Herstellung von Kernteilchen, die hydrophile Polymere wie Agarose, Polyacrylamid, wasserlösliche Cellulosederivate, Polyvinylalkohol, Gelatine und hydrophile Farbstoffe enthalten, geht man umgekehrt vor. Man löst die Polymeren und die Farbstoffe in Wasser und emulgiert diese Lösung wieder unter Anwendung von grenzflächenaktiven Stoffen in einem organischen Lösungsmittel, dessen Siedepunkt oberhalb des Siedepunktes von Wasser liegt. Geeignet sind hierfür beispielsweise Toluol, Ethylbenzol, Xylole, Cu ol. Nach dem Vermischen beider Phasen unter Einsatz eines hochtourigen Rührwerks wird eine feinteilige Emulsion mit dem organischen Lösungsmittel als kontinuierliche Phase erhalten. In den feinverteilten Wassertropfen befinden sich das Polymermaterial und die Farbstoffe. Nach Abdestillieren des Wassers verfestigen sich diese Tröpfchen zu sphäroiden Mikroteilchen. Diese werden wieder durch Zentrifugieren isoliert.The process is reversed in the production of core particles which contain hydrophilic polymers such as agarose, polyacrylamide, water-soluble cellulose derivatives, polyvinyl alcohol, gelatin and hydrophilic dyes. The polymers and the dyes are dissolved in water and this solution is emulsified again using surfactants in an organic solvent whose boiling point is above the boiling point of water. For example, toluene, ethylbenzene, xylenes, Cu ol are suitable for this. After the two phases have been mixed using a high-speed stirrer, a finely divided emulsion with the organic solvent is obtained as a continuous phase. The polymer material and the dyes are in the finely divided water drops. After the water has been distilled off, these droplets solidify into spheroidal microparticles. These are isolated again by centrifugation.
Erfindungsgemäß lassen sich auch polymere Mikroteilchen, die an ihrer Oberfläche anionen- oder kationenaustauschende Gruppen enthalten, wie entsprechend modifizierte Styrol- Divinyl-Copolymere, mit ionischen Farbstoffen beladen.According to the invention, polymeric microparticles which contain anion- or cation-exchanging groups on their surface, such as appropriately modified styrene-divinyl copolymers, can also be loaded with ionic dyes.
Im zweiten Schritt werden diese fluoreszierenden Kernteilchen mit einem bei den optischen Frequenzen der Anregung und Fluoreszenz metallisch leitenden Material beschichtet. Hierfür sind insbesondere Gold, Silber, Kupfer oder Aluminium geeignet. In Abhängigkeit von der Größe der Kernteilchen sind hierbei bestimmte Schichtdicken im Bereich von 1 bis 10 nm besonders bevorzugt, um maximale Photostabilität und/oder Fluoreszenzintensität zu erreichen.In the second step, these fluorescent core particles are coated with a material that is metallically conductive at the optical frequencies of excitation and fluorescence. Gold, silver, copper or aluminum are particularly suitable for this. Depending on the size of the core particles, certain layer thicknesses in the range from 1 to 10 nm are particularly preferred in order to achieve maximum photostability and / or fluorescence intensity.
Diese erfindungsgemäße Verbesserung der Fluoreszenzeigenschaften hängt in komplexer Weise von den Materialeigenschaften der beteiligten Stoffe (Polymermaterial und Farbstoffe), Art des metallisch leitenden Materials, den geometrischen Verhältnissen (Durchmesser der Kernteilchen und Schichtdicke des metallisch leitenden Materials) und der Art der Anregung und Emission (Ein- oder Mehrphotonenanregung) ab.This improvement in fluorescence properties according to the invention depends in a complex manner on the material properties of the substances involved (polymer material and dyes), type of metallically conductive material, the geometric relationships (diameter of the core particles and layer thickness of the metallically conductive material) and the type of excitation and emission (a - or multi-photon excitation).
Die Beschichtung der fluoreszierenden Kernteilchen erfolgt durch Dispergieren dieser Teilchen in einem Lösungsmittel bevorzugt in wässrigem Medium, Zugabe eines Salzes oder einer anderen Verbindung des metallisch leitenden Materials und eines Reduktionsmittels. Als Metallsalze eignen sich beispielsweise Silbersulfat, Silbernitrat, Gold(HI)chlorid, Gold(I)cyanid, Kupfersulfat, Kupfernitrat. Für Silber bzw. Gold eignen sich eine Vielzahl von Reduktionsmitteln. Die folgende Aufzählung stellt eine Auswahl ohne Anspruch auf Vollzähligkeit dar: Formaldehyd, Eisen(II)sulfat, Weinsäure, Hydrochinon, p-Aminophenol, Dialky- laniline, Phenidon, Sulfit, Oxalsäure, Zucker, Weinsäure, Citronensäure. Zweckmäßigerweise werden Lösungen der Metallsalze und des Reduktionsmittels abwechselnd in kleinen Portionen zu den dispergierten Kernteilchen gegeben und Proben entnom- men, um den Vorgang der Beschichtung zu verfolgen und zu kontrollieren. Die entnommenen Proben werden auf ihre Fluoreszenzeigenschaften im Vergleich zu den unbeschichteten Kernteilchen untersucht. Die Dicke der Beschichtung wird durch Ablösen der Metallschicht von einer definierten Anzahl von Mikroteilchen und analytische Bestimmung der Metallionenkonzentration ermittelt. Hierfür werden beispielsweise Polarographie oder Atomabsorptionsspektroskopie verwendet.The fluorescent core particles are coated by dispersing these particles in a solvent, preferably in an aqueous medium, adding a salt or another compound of the metallically conductive material and a reducing agent. Suitable metal salts are, for example, silver sulfate, silver nitrate, gold (HI) chloride, gold (I) cyanide, copper sulfate, copper nitrate. A large number of reducing agents are suitable for silver or gold. The following list represents a selection without claim to completeness: formaldehyde, iron (II) sulfate, tartaric acid, hydroquinone, p-aminophenol, dialkylaniline, phenidone, sulfite, oxalic acid, sugar, tartaric acid, citric acid. Solutions of the metal salts and the reducing agent are expediently added alternately in small portions to the dispersed core particles and samples are taken. to track and control the coating process. The samples taken are examined for their fluorescence properties in comparison to the uncoated core particles. The thickness of the coating is determined by detaching the metal layer from a defined number of microparticles and analytically determining the metal ion concentration. For example, polarography or atomic absorption spectroscopy are used for this.
Dabei haben sich Schichtdicken des metallisch leitenden Materials im Bereich von 1 bis 10 nm und fluoreszierende Kernteilchen mit einem Durchmesser von 10 bis 90 nm als geeignet erwiesen. Besonders geeignet sind Kernteilchen deren Durchmesser 10 bis 50 nm beträgt, wenn als metallisch leitendes Material Silber verwendet wird.Layer thicknesses of the metallically conductive material in the range from 1 to 10 nm and fluorescent core particles with a diameter of 10 to 90 nm have proven to be suitable. Core particles with a diameter of 10 to 50 nm are particularly suitable if silver is used as the metallic conductive material.
In einem weiteren Arbeitsschritt kann die Oberfläche der metallisierten Teilchen modifiziert werden, um das Ankoppeln insbesondere von biologisch oder medizinisch relevanten Substanzen zu bewirken. Hierfür gibt es eine Reihe von Varianten, die separat und/oder in Kombination angewendet werden können. Durch Behandlung mit Oxidationsmitteln oder Ammoniumsulfidlösungen wird auf den metallisierten Oberflächen eine dünne Schutzschicht erzeugt. Hierfür eignen sich auch aliphatische Polysulfide oder monomere thiolgruppenenthal- tende Substanzen.In a further step, the surface of the metallized particles can be modified in order to bring about the coupling in particular of biologically or medically relevant substances. There are a number of variants that can be used separately and / or in combination. Treatment with oxidizing agents or ammonium sulfide solutions creates a thin protective layer on the metallized surfaces. Aliphatic polysulfides or monomeric substances containing thiol groups are also suitable for this.
Um das weitere Ankoppeln von Biomaterialien zu ermöglichen kann eine Beschichtung mit Eiweißkörpera wie Albumin oder anderen Substanzen, die funktionelle Gruppen enthalten, erfolgen. Als Beschichtungsmaterial eignen sich eine Vielzahl von monomeren oder polyme- ren Substanzen wie Styrol-Maleinsäure-Copolymere, Polyvinylalkohol und Polyvinylalko- holderivate, lösliche Cellulosederivate, Azide, Diazide, Chinondiazide. Auf diese Weise können die fluoreszierenden Mikroteilchen mit funktioneilen Gruppen, wie Hydroxyl, Amin, Amid, Imid, Carbonsäureanhydrid, Sulfhydryl, Sulfonat, Aldehyd, Azid, Chinonazid oder biologisch aktive Substanzen ausgerüstet werden. Für die Anwendung in der Bioanalytik ist die Beschichtung mit bzw. Ankopplung von Biotin, Avidin, Streptavidin, oder Nucleinsäureverbindungen besonders attraktiv.In order to enable the further coupling of biomaterials, they can be coated with protein bodies such as albumin or other substances which contain functional groups. A large number of monomeric or polymeric substances such as styrene / maleic acid copolymers, polyvinyl alcohol and polyvinyl alcohol derivatives, soluble cellulose derivatives, azides, diazides, quinonediazides are suitable as coating material. In this way, the fluorescent microparticles can be equipped with functional groups such as hydroxyl, amine, amide, imide, carboxylic anhydride, sulfhydryl, sulfonate, aldehyde, azide, quinone azide or biologically active substances. The coating with or coupling of biotin, avidin, streptavidin or nucleic acid compounds is particularly attractive for use in bioanalytics.
Die erfindungsgemäßen fluoreszierenden Mikroteilchen werden als Fluoreszenzmarker oder Tracer verwendet. Die Verwendung als Fluoreszenzmarker benutzt dabei die Möglichkeit, daß die an den Mikroteilchen gebundenen funktioneilen Gruppen oder biologisch aktiven Substanzen mit Analytsubstanzen reagieren und anschließend über eine Fluoreszenzmessung detektiert werden können. Die übliche Vorgehensweise ist dabei folgende: a) Es wird eine Probe in der sich die nachzuweisenden Analytsubstanzen befinden vorbereitet. b) Fluoreszierende Mikroteilchen mit funktioneilen Gruppen oder biologisch aktiven Substanzen ausgerüstet, die zur Erkennung der Analytsubstanzen fähig sind, werden disper- giert oder in geeigneter Weise auf eine Oberfläche aufgebracht. c) Die Analytsubstanzen und die fluoreszierenden Mikroteilchen werden zusammengebracht und für die benötigte Reaktionszeit inkubiert. d) Mikroteilchen, die nicht reagiert haben, werden entfernt. e) Die gebundenen Mikroteilchen und damit die Analytsubstanzen werden bestrahlt und über das abgestrahlte Fluoreszenzlicht detektiert.The fluorescent microparticles according to the invention are used as fluorescent markers or tracers. The use as a fluorescence marker uses the possibility that the functional groups or biologically active substances bound to the microparticles react with analyte substances and can subsequently be detected by means of a fluorescence measurement. The usual procedure is as follows: a) A sample is prepared in which the analyte substances to be detected are located. b) Fluorescent microparticles equipped with functional groups or biologically active substances which are capable of recognizing the analyte substances are dispersed or applied in a suitable manner to a surface. c) The analyte substances and the fluorescent microparticles are brought together and incubated for the required reaction time. d) Microparticles that have not reacted are removed. e) The bound microparticles and thus the analyte substances are irradiated and detected using the emitted fluorescent light.
Nach diesem Schema lassen sich Proteine, Peptide, DNA, RNA, Oligonucleotide, Polysaccha- ride, Avidin, Biotin, polymere und nichtpolymere Biomoleküle, Antikörper, Antigene, Viren oder andere Mikroorganismen nachweisen.Proteins, peptides, DNA, RNA, oligonucleotides, polysaccharides, avidin, biotin, polymeric and non-polymeric biomolecules, antibodies, antigens, viruses or other microorganisms can be detected according to this scheme.
Das beschriebene Verfahren kann auch speziell als Immunoassay ausgestaltet werden. Die Detektion von DNA, RNA oder Oligonucleotiden kann in der DNA-Sequenzanalyse verwendet werden. Mit fluoreszierenden Mikroteilchen markierte Zellen können aussortiert oder cytometrisch detektiert werden.The method described can also be specifically designed as an immunoassay. The detection of DNA, RNA or oligonucleotides can be used in DNA sequence analysis. Cells labeled with fluorescent microparticles can be sorted out or cytometrically detected.
Die erfindungsgemäßen fluoreszierenden Mikroteilchen lassen sich auch als Tracer zur Untersuchung von Transportvorgängen in fluiden Medien innerhalb und außerhalb von lebenden Organismen oder Zellen anwenden.The fluorescent microparticles according to the invention can also be used as tracers for examining transport processes in fluid media inside and outside of living organisms or cells.
Die hohe Fluoreszenzintensität der erfindungsgemäßen Mikroteilchen bei Zweiphotonenanregung erlaubt eine Anregung mit preiswerten kommerziellen Diodenlasern im Bereich 600- 1100 nm und die Detektion der kurzwellig dazu emittierten Fluoreszenzstrahlung im Bereich von 300-700 nm. Wegen der hohen Fluoreszenzintensität und der verbesserten Photo Stabilität lassen sich mit den erfindungsgemäßen Mikroteilchen vielfach Detektionsverfahren einfacher und wirtschaftlich günstiger gestalten. Beispielsweise ist die Detektion der fluoreszierenden Mikroteilchen auch mit einer CCD-Kamera möglich.The high fluorescence intensity of the microparticles according to the invention with two-photon excitation allows excitation with inexpensive commercial diode lasers in the range 600-1100 nm and the detection of the short-wave fluorescence radiation emitted in the range 300-700 nm. Because of the high fluorescence intensity and the improved photo stability, the Microparticles according to the invention in many cases make the detection method simpler and more economical. For example, the detection of the fluorescent microparticles is also possible with a CCD camera.
Im folgenden wird die Erfindung anhand von Ausführungsbeispielen näher erläutert, ohne auf diese Beispiele beschränkt zu sein.The invention is explained in more detail below on the basis of exemplary embodiments, without being restricted to these examples.
Beispiel 1example 1
In 250ml doppelt destilliertem Wasser werden lg Polystyrollatexpartikel deren mittlerer Teilchendurchmesser 50 nm beträgt und die mit einem bei einer Wellenlänge von 635 nm anregbaren Cyaninfarb Stoff Fl (die Formel ist unter Figure 1 angegeben) beladen sind unter intensivem Rühren dispergiert. Um diese fluoreszierenden Kernteilchen mit Silber zu beschichten, werden zwei Lösungen bereitet.In 250 ml of double-distilled water, 1 g of polystyrene latex particles whose average particle diameter is 50 nm and which are loaded with a cyanine dye Fl which can be excited at a wavelength of 635 nm (the formula is given under Figure 1) are dispersed with vigorous stirring. In order to coat these fluorescent core particles with silver, two solutions are prepared.
Lösung A : 2%-ige Lösung von Silbernitrat in doppelt destilliertem Wasser Lösung B : In 250 ml doppelt destilliertem Wasser werden gelöst 2g p-Aminophenol und 10g KaliumcarbonatSolution A: 2% solution of silver nitrate in double distilled water Solution B: 2g p-aminophenol and 10g potassium carbonate are dissolved in 250 ml double distilled water
Beide Lösungen werden auf 25 Grad C temperiert.Both solutions are tempered to 25 degrees C.
Zu der Suspension mit den farbstoffbeladenen Latexpartikeln werden anschließend 10 ml Lösung A und 20 ml Lösung B gegeben. Nach einer Reaktionszeit von 25 min werden anschließend 30 ml Reaktionsgemisch mit einer Pipette entnommen, die Latexpartikel durch zentrifugieren isoliert und drei Mal mit doppelt destilliertem Wasser gewaschen. Anschließend wird diese Prozedur mit der verbleibenden Reaktionsmischung noch vier Mal wiederholt, so daß man eine Reihe unterschiedlich mit Silber beschichteter Latexpartikel erhält. Die isolierten und gewaschenen Latexpartikel werden in 100 ml doppelt destilliertem Wasser dispergiert, um die Fluoreszenzeigenschaften bei Anregung mit der Wellenlänge 635 nm bei der Emissionswellenlänge 670 nm zu messen. Das erfogt mittels einer herkömmlichen Fluorime- teranordnung unter Anregung mit einem Diodenlaser. Dabei dienen die nicht mit Silber beschichteten Polystyrolpartikel als Referenzobjekt. Als Photostabilität wird die Zahl der detek- tierbaren Fluoreszenzphotonen bis zu einer Abnahme der Fluoreszenzintensität auf den halben Ausgangswert (Halbwertzeit) definiert.10 ml of solution A and 20 ml of solution B are then added to the suspension with the dye-laden latex particles. After a reaction time of 25 min, 30 ml of reaction mixture are then removed with a pipette, the latex particles are isolated by centrifugation and washed three times with double-distilled water. This procedure is then repeated four more times with the remaining reaction mixture, so that a number of latex particles coated differently with silver are obtained. The isolated and washed latex particles are dispersed in 100 ml of double distilled water in order to measure the fluorescence properties when excited with the wavelength 635 nm at the emission wavelength 670 nm. This is done using a conventional fluorimeter arrangement under excitation with a diode laser. The polystyrene particles not coated with silver serve as reference objects. The number of detectable fluorescence photons up to a decrease in the fluorescence intensity to half the initial value (half-life) is defined as photostability.
Nach der Messung wird die Menge des auf den Teichen abgeschiedenen Silbers bestimmt. Dazu wird das Silber mit einer Kaliumferricyanidlösung oxidativ in Lösung gebracht und polarographisch bestimmt.After the measurement, the amount of silver deposited on the ponds is determined. For this purpose, the silver is oxidatively dissolved in a potassium ferricyanide solution and determined by polarography.
Es wurde gefunden, daß die Verbesserung der Fluoreszenzeigenschaften in komplexer Weise von der Größe der Kernteilchen und der Schichtdicke des aufgebrachten Silbers abhängt. Im Vergleich zu den unbeschichteten Mikroteilchen wurde eine maximale Erhöhung der Fluoreszenz um den Faktor 22 und der Photo Stabilität um den Faktor 100 bei einem Teilchendurchmesser von 50 nm und einer Silberschichtdicke von 6 nm gefunden. Beispiel 2It has been found that the improvement in the fluorescence properties depends in a complex manner on the size of the core particles and the layer thickness of the applied silver. In comparison with the uncoated microparticles, a maximum increase in fluorescence by a factor of 22 and photo stability by a factor of 100 was found with a particle diameter of 50 nm and a silver layer thickness of 6 nm. Example 2
In diesem Beispiel wird analog Beispiel 1 die Beschichtung von Mikroteilchen mit Gold und die Bestimmung der Fluoreszenzeigenschaften der erhaltenenTeilchen bei Einphotonenanregung bei der Wellenlänge 635 nm und Emission bei 670 nm beschrieben. Es werden wieder lg der farbstofϊbeladenen Polystyrolmikroteilchen analog Beispiel 1 in 250 ml doppelt destilliertem Wasser dispergiert und die folgenden Lösungen bereitet: Lösung A: 3 % ige Lösung von Tetrachlorogoldsäuretrihydrat in 11 doppelt destilliertem WasserIn this example, the coating of microparticles with gold and the determination of the fluorescence properties of the particles obtained with single-photon excitation at the wavelength 635 nm and emission at 670 nm are described as in Example 1. Again, 1 g of the dye-loaded polystyrene microparticles are dispersed analogously to Example 1 in 250 ml of double-distilled water and the following solutions are prepared: Solution A: 3% solution of tetrachloroauric acid trihydrate in 11 double-distilled water
Lösung B: 2,5 % ige Lösung von Kaliumcarbonat in 11 doppelt destillieretem Wasser Lösung C: 3 ml 37 % ige Formaldehydlösung gelöst in 11 doppelt destilliertem Wasser Zu 250 ml der Dispersion , die lg farbstoffbeladene Polystyrolmikroteilchen analog Beispiel 1 enthält, werden 10 ml Lösung A, 8 ml Lösung B und 20 ml Lösung C gegeben. Das Reaktionsgemisch wird auf 80 Grad C erwärmt und nach 10 Minuten eine Probe entnommen. Nach Zentrifugieren und Waschen werden jeweils analog Beispiel 1 die Fluoreszenzeigenschaften der goldbeschichtete Mikroteilchen bestimmt. Der Goldgehalt der Mikroteilchen wird nach Ablösen des Goldes in Königswasser wieder polarograflsch bestimmt. Durch mehrfache Wiederholung dieser Prozedur erhält man Mikroteilchen mit unterschiedlicher Goldbeschichtung.Solution B: 2.5% solution of potassium carbonate in 11 double-distilled water Solution C: 3 ml 37% formaldehyde solution dissolved in 11 double-distilled water To 250 ml of the dispersion, which contains lg of dye-loaded polystyrene microparticles analogous to Example 1, add 10 ml of solution A, 8 ml of solution B and 20 ml of solution C. The reaction mixture is heated to 80 degrees C and a sample is taken after 10 minutes. After centrifugation and washing, the fluorescence properties of the gold-coated microparticles are determined in each case analogously to Example 1. The gold content of the microparticles is determined polarographically again after the gold has been dissolved in aqua regia. By repeating this procedure several times, microparticles with different gold plating are obtained.
Für Teilchen mit einem Durchmesser von 50 nm wird bei einer aufgebrachten Goldschicht von 9 nm eine Erhöhung der Fluoreszenzintensität um den Faktor 13 und eine Verbesserung der Photostabilität um den Faktor 60 im Vergleich zu den unbeschichteten fluoreszierenden Polystyrolpartikeln festgestellt.For particles with a diameter of 50 nm, with an applied gold layer of 9 nm, an increase in the fluorescence intensity by a factor of 13 and an improvement in the photostability by a factor of 60 is found in comparison to the uncoated fluorescent polystyrene particles.
Beispiel 3Example 3
Beispiel 3 beschreibt die Bestimmung der Fluoreszenzeigenschaften für Zweiphotonenanregung. Als Ausgangsmaterial dienten dabei Polystyrolmikroteilchen von einem Durchmesser von 50 nm die mit dem Farbstoff Rhodamin 6G beladen waren. Die Beschichtung dieser Mikroteilchen mit Silber bzw. Gold erfolgte analog Beispiel 1 und Beispiel 2. Zur Bestimmung der Fluoreszenzeigenschaften wurde mit einem gepulsten Diodenlaser (Pulswiederholrate 80 MHz, Pulsbreite 50 ps) auf der Wellenlänge 790 nm angeregt und die Fluoreszenzemission bei Wellenlängen im Bereich von 450 - 600 nm gemessen. Für Mikroteilchen mit einem Kerndurchmesser von 50 nm und einer Silberbeschichtung von 6 nm ergab sich beispielsweise eine Erhöhung der Fluoreszenzintesität um den Faktor 1000 gegenüber den nicht metallisierten Teilchen bei der Messung des Fluoreszenzlichts bei der Wellenlänge 460 nm. Die Photostabilität erhöhte sich für diese Mikroteilchen unter den gleichen Meßbedingungen etwa um den Faktor 2.Example 3 describes the determination of the fluorescence properties for two-photon excitation. The starting material used was polystyrene microparticles with a diameter of 50 nm, which were loaded with the dye rhodamine 6G. The coating of these microparticles with silver or gold was carried out analogously to Example 1 and Example 2. To determine the fluorescence properties, a pulsed diode laser (pulse repetition rate 80 MHz, pulse width 50 ps) was excited at the wavelength of 790 nm and the fluorescence emission at wavelengths in the range of 450 - 600 nm measured. For microparticles with a core diameter of 50 nm and a silver coating of 6 nm, for example, the fluorescence intensity increased by a factor of 1000 compared to the non-metallized particles when measuring the fluorescent light at the wavelength of 460 nm. The photostability for these microparticles increased among the same measurement conditions by a factor of 2.
Für mit Gold beschichtete Teilchen wurde maximal eine Erhöhung der Fluoreszenzintensität um etwa den Faktor 200 gefunden für Kernteilchen mit einem Durchmesser von 50 nm und einer Goldbeschichtung von 7 nm. For gold-coated particles, a maximum increase in fluorescence intensity of around a factor of 200 was found for core particles with a diameter of 50 nm and a gold coating of 7 nm.
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| CN110672574B (en) * | 2019-11-06 | 2021-10-15 | 湖北师范大学 | A ratiometric fluorescence sensor for detecting Cu2+ and its preparation method and application |
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| WO2003035795A3 (en) * | 2001-10-25 | 2003-06-05 | Univ Manchester | Photostabilised organic material |
| EP1590659A4 (en) * | 2003-02-07 | 2010-04-21 | Univ Texas | MULTICHIECH MICROSPHERES WITH INTEGRATED CHROMATOGRAPHIC AND DETECTION LAYERS USED IN MOSAIC SENSORS |
| WO2006084339A1 (en) * | 2005-02-14 | 2006-08-17 | Australian Nuclear Science & Technology Organisation | Layered nanoparticles |
| US8871272B2 (en) | 2005-02-14 | 2014-10-28 | Australian Nuclear Science & Technology Organisation | Layered nanoparticles |
| US9295654B2 (en) | 2005-02-14 | 2016-03-29 | Australian Nuclear Science & Technology Organisation | Layered nanoparticles |
| WO2008127139A1 (en) * | 2007-04-11 | 2008-10-23 | Institut Molekulyarnoi Biologii Im. V.A. Engeldardta Rossiiskoi Akademii Nauk | Indicyanine dyes and the derivatives thereof for analysing biological micromolecules |
| CN102598625A (en) * | 2009-11-09 | 2012-07-18 | 三星电子株式会社 | Method and apparatus for changing input type in input system using universal plug and play |
| CN102598625B (en) * | 2009-11-09 | 2015-07-01 | 三星电子株式会社 | Method and apparatus for changing input type in input system using universal plug and play |
| CN102516696A (en) * | 2011-12-19 | 2012-06-27 | 东南大学 | Method for preparing bioluminescent nano thermometer |
| CN105985598A (en) * | 2016-06-17 | 2016-10-05 | 燕山大学 | Dye-graphene-polyvinyl alcohol ternary fluorescent complex and preparation method |
| DE102017114537A1 (en) | 2017-06-29 | 2019-01-03 | Endress+Hauser Conducta Gmbh+Co. Kg | Sensor membrane, sensor cap and optical sensor |
| CN108586758A (en) * | 2018-05-10 | 2018-09-28 | 宁波新斯维箱包有限公司 | Microcapsules and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| DE10108808A1 (en) | 2002-09-05 |
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