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US 4,698,302 AGranted
Enzymatic reactions using magnetic particles
AssigneeAdvanced Magnetics, Inc.
InventorsRoy A. Whitehead, Mark S. Chagnon, Ernest V. Groman, Lee Josephson
Life of this patent
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Abstract
A process is provided for the preparation of magnetic particles to which a wide variety of molecules may be coupled. The magnetic particles can be dispersed in aqueous media without rapid settling and conveniently reclaimed from media with a magnetic field. Preferred particles do not become magnetic after application of a magnetic field and can be redispersed and reused. The magnetic particles are useful in biological systems involving separations.
Claims16
A method for carrying out an enzymatic reaction which comprises:
- (a) contacting an enzyme covalently coupled to magnetically-responsive particles with a reaction medium to form a reaction mixture in a reaction vessel to effect an enzymatic reaction;
- (b) allowing the enzymatic reaction to occur;
- and
- (c) removing the enzyme from the reaction mixture by applying a magnetic field,
- wherein the magnetically-responsive particles of step (a) individually comprise a magnetic metal oxide core generally surrounded by a coat of polymeric silane, a mass of the particles being dispersable in aqueous media to form an aqueous dispersion having (i) a fifty-percent-turbidity-decrease settling time of greater than about 1.5 hours in the absence of a magnetic field, and (ii) a ninty-five-percent-turbidity-decrease separation time of less than about 10 minutes in the presence of a magnetic field, the magnetic field being applied to the aqueous dispersion by bringing a vessel containing a volume of the dispersion into contact with a pole face of a permanent magnet, the permanent magnet having a volume which is less than the volume of the aqueous dispersion in the vessel.
2 more elements
A method for carrying out an enzymatic reaction which comprises:
- (a) contacting an enzyme covalently coupled to magnetically-responsive particles with a reaction medium to form a reaction mixture in a reaction vessel to effect an enzymatic reaction;
- (b) allowing the enzymatic reaction to occur;
- and
- (c) removing the enzyme from the reaction mixture by applying a magnetic field,
- wherein the magnetically-responsive particles of step (a) individually comprise a superparamagnetic iron oxide core generally surrounded by a coat of polymeric silane, the iron oxide core including a group of crystals of iron oxide, an individual particle having a mean diameter as measured by light scattering between about 0.1.mu. and about 1.5.mu. and a surface area as measured by nitrogen gas adsorption of at least about 100 m.sup.2 /gm, a mass of the particles being dispersable in aqueous media to form an aqueous dispersion having (i) a fifty-percent-turbidity-decrease settling time of greater than about 1.5 hours in the absence of a magnetic field, and (ii) a ninety-five-percent-turbidity-decrease separation time of less than about 10 minutes in the presence of a magnetic field, the magnetic field being applied to the aqueous dispersion by bringing a vessel containing a volume of the dispersion into contact with a pole face of a permanent magnet, the permanent magnet having a volume which is less than the volume of the aqueous dispersion in the vessel.
2 more elements
A method for carrying out an enzymatic reaction which comprises:
- (a) contacting an enzyme covalently coupled to magnetically-responsive particles with a reaction medium to form a reaction mixture in a reaction vessel to effect an enzymatic reaction;
- (b) allowing the enzymatic reaction to occur;
- and
- (c) removing the enzyme from the reaction mixture by applying a magnetic field,
- wherein the magnetically-responsive particles of step (a) individually comprise a ferromagnetic metal oxide core generally surrounded by a coat of polymeric silane, the metal oxide core including a group of crystals of metal oxide, an individual particle having a mean diameter as measured by light scattering between about 0.1.mu. and about 1.5.mu. and a surface area as measured by nitrogen gas adsorption of at least about 100 m.sup.2 /gm, a mass of the particles being dispersable in aqueous media to form an aqueous dispersion having (i) a fifty-percent-turbidity-decrease settling time of greater than about 1.5 hours in the absence of a magnetic field, and (ii) a ninety-five-percent-turbidity-decrease separation time of less than about 10 minutes in the presence of a magnetic field, the magnetic field being applied to the aqueous dispersion by bringing a vessel containing a volume of the dispersion into contact with a pole face of a permanent magnet, the permanent magnet having a volume which is less than the volume of the aqueous dispersion in the vessel.
2 more elements
Dependencies are inferred from the claim text.